deliverable 3.1 report about the requirements for masonry...

DEVELOPING INNOVATIVE SYSTEMS FOR REINFORCED MASONRY WALLS

COOP-CT-2005 CONTRACT N. 018120

Product Development D3.1 of 35

Deliverable 3.1

Report about the requirements for masonry units, reinforcement, mortar

and concrete

Due date: July 2006 Submission date: July 2006

Issued by: RWTH

WORKPACKAGE 3: Product development (Leader: RWTH)

PROJECT N°: COOP-CT-2005-018120

ACRONYM: DISWall

TYTLE: Developing Innovative Systems for Reinforced Masonry Walls

COORDINATOR: Università di Padova (Italy)

START DATE: 16 January 2006 DURATION: 24 months

INSTRUMENT: Co-operative Research Project

THEMATIC PRIORITY: Horizontal Research activities involving SMEs

a) unit material b) concrete infill

Hollow clay unit filled with concrete subjected to vertical load (RWTH)

Dissemination level: PU Rev: FINAL




INDEX

INDEX................................................................................................................................................................ 2 1 INTRODUCTION........................................................................................................................................ 3

1.1 OVERVIEW......................................................................................................................................... 3 1.2 DESCRIPTION OF THE WORKPACKAGE........................................................................................ 3

2 STATE OF THE ART.................................................................................................................................. 4 2.1 INTRODUCTION................................................................................................................................. 4 2.2 REQUIREMENTS ON THE MASONRY UNITS ................................................................................. 4 2.3 REQUIREMENTS ON THE MORTAR.............................................................................................. 10 2.4 PROPERTIES OF COMMONLY USED CONCRETE ...................................................................... 14 2.5 REQUIREMENTS ON THE REINFORCEMENT AND THE FASTENINGS..................................... 16

3 PERFORATED CLAY UNITS................................................................................................................... 17 3.1 REASONS FOR AND AIMS OF THE INVESTIGATIONS................................................................ 17 3.2 INVOLVED PARTNERS AND PLANNED TASKS............................................................................ 18 3.3 SELECTED APPROACH.................................................................................................................. 20 3.4 CONSTRAINTS AND REQUIREMENTS FOR THE REINFORCEMENT ........................................ 21 3.5 DESIGN OF PERFORATED CLAY MASONRY UNITS ................................................................... 21 3.6 BEDDING/FILLING MORTAR........................................................................................................... 21

4 LARGE HOLLOW CLAY UNITS .............................................................................................................. 23 4.1 REASONS FOR AND AIMS OF THE INVESTIGATIONS................................................................ 23 4.2 INVOLVED PARTNERS AND PLANNED TASKS............................................................................ 24 4.3 SELECTED APPROACH.................................................................................................................. 26 4.4 CONSTRAINTS AND REQUIREMENTS FOR REINFORCEMENT, FASTENINGS, MASONRY

UNITS AND CONCRETE INFILL................................................................................................................. 27 5 CONCRETE UNITS.................................................................................................................................. 29

5.1 REASONS FOR AND AIMS OF THE INVESTIGATIONS................................................................ 29 5.2 INVOLVED PARTNERS AND PLANNED TASKS............................................................................ 31 5.3 SELECTED APPROACH.................................................................................................................. 32 5.4 CONSTRAINTS AND REQUIREMENTS FOR THE REINFORCEMENT AND THE FASTENINGS32 5.5 DESIGN OF HOLLOW CONCRETE MASONRY UNITS ................................................................. 32 5.6 BEDDING/FILLING MORTAR AND GROUT.................................................................................... 34




1 INTRODUCTION

1.1 OVERVIEW

Within this document, a state of the art on the requirements on the aimed masonry components - masonry

units, mortar, reinforcement and fastenings, concrete - is compiled in section 2. In section 2.2 concerning the

state of the art on the masonry units a distinction between clay units and concrete units is made, which is

pursued in the following sections 3, 4 and 5. These sections contain the reasons for and aim of the

investigations, the planned tasks of the involved partners and the descriptions of the different approaches.

1.2 DESCRIPTION OF THE WORKPACKAGE

The goals of this Workpackage are:

- the development or the further development respectively of masonry units and their production,

- the development of suitable reinforcement and fastenings and their production,

- the development of a special purpose mortar,

- the development of a self-compacting concrete,

- the determination of material properties.

In general, in the sections 3, 4 and 5, it is distinguished between three different approaches for the

development of reinforced masonry systems, namely masonry made of:

- perforated clay units,

- large hollow clay units,

- concrete units.

The concepts, which were developed to reach the declared aims, are mentioned in the sections 3, 4 and 5.




2 STATE OF THE ART

2.1 INTRODUCTION

Within the following sections the state of the art on the requirements or the range of values of the properties

of the masonry components, i.e. masonry units, mortar, concrete and reinforcement, are compiled.

Furthermore the respective testing standards or regulations are given.

2.2 REQUIREMENTS ON THE MASONRY UNITS

The tables 1 to 4 contain the requirements on different properties of clay and concrete units. When specified,

instead of code given requirements, the property ranges given by producers and used up to now are given. It

is distinguished between geometrical properties (cf. table 1), physical properties (cf. table 2), durability

properties (cf. table 3) and mechanical properties (cf. table 4). Furthermore, the tables contain the testing

standards or regulations respectively used to determine the mentioned properties.




Table 1: Requirements on the geometrical properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIREMENT TEST METHOD

CODE REQUIRED PERFORMANCE

NOTES CODE REQUIRED PERFORMANCE

NOTES

1 2 3 4 5 6

Percentage of voids EN 772-2:2001 Methods of test for masonry units - Determination of percentage area of voids in aggregate concrete masonry units (by paper indentation) EN 772-3:2000 Methods of test for masonry units - Determination of net volume and percentage of voids of clay masonry units by hydrostatic weighing EN 772-9, methods of test for masonry units – Determination of volume and percentage of voids and net volume of clay and calcium silicate masonry units by sand filling

Group 2, 25% < φ ≤ 55%; Group 3, 25% < φ ≤ 70%; Group 4, 25% < φ ≤ 70%, horizontal holes (EN 1996-1-1, 2005) 15% < φ ≤ 45% 45% < φ ≤ 55%; (D.M. 20/11/87, D.M 14/9/2005) φ ≤ 45% (load-bearing walls in seismic area) (OPCM 3431) (EN 771-1:2005)

The percentage is related to the gross area

Group 2 25% < φ ≤ 55%; Group 3 25% < φ ≤ 70%; Group 4 (horizontal holes) 25% < φ ≤ 70% (EN 1996-1-1, 2005)

The percentage is related to the gross area

Transversal surface of any hole, (both deep and through holes)

- Multiple holes: Group 2 & 3, ≤ 2%; Group 4, ≤ 30%, Gripholes holes: Group 2 & 3, ≤ 12.5%; Group 4, ≤ 30%, (EN 1996-1-1, 2005) Multiple holes: for 15%< φ ≤ 45%,≤ 12 cm2 for 45%< φ ≤ 55%, ≤ 15 cm2 Gripholes holes: for A = 300 cm2, 1 hole ≤ 35cm2, for A = 580 cm2, 2 holes ≤ 35cm2

(D.M. 20/11/87) In seismic area: 1 hole ≤ 70cm2, (OPCM 3431)

- Multiple holes: Group 2 and 3, ≤ 30%; Group 4, ≤ 25%; Gripholes: Group 2 and 3, ≤ 30%; Group 4, ≤25%

-




Table 1: (continued) Requirements on the geometrical properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIREMENT TEST METHOD



NOTES

1 2 3 4 5 6

Dimensions EN 772-16:2002 Methods of test for masonry units - Determination of dimensions

(EN 771-1:2005) h = 5 – 20 cm, l = 25 – 30 cm, b = 12 – 35 cm

(EN 771-3:2003) -

Thickness of webs and shells

EN 772-16:2005 Methods of test for masonry units - Determination of dimensions

Web: Group 2, ≥ 5mm; Group 3, ≥ 3mm. Shell: Group 2, ≥ 8mm; Group 3, ≥ 6mm. (EN 1996-1-1, 2005) Web: ≥8mm; Shell: ≥ 10mm; (D.M. 20/11/87, D.M 14/9/2005) Webs ║ to plane of wall must be in a straight line (OPCM 3431)

Web: ≥ 14 mm Shell: ≥ 20 mm (EN 771-1:2005)

Web: Group 2 and 3 ≥ 15mm; Group 4, ≥ 20mm. Shell: Group 2, ≥ 18mm; Group 3, ≥ 15mm; Group 4, ≥ 20mm. (EN 1996-1-1, 2005)

-

Combined thickness of webs and shells

EN 772-16:2005 Methods of test for masonry units - Determination of dimensions prEN 1996-1-1:2004 (Table 3.1)

Group 2, ≥ 16mm; Group 3, ≥ 12mm. (EN 1996-1-1, 2005)

- Group 2, ≥ 18mm; Group 3, ≥ 15mm; Group 4, ≥ 45mm. (EN 1996-1-1, 2005)

-

Flatness of faces EN 772-20:2005 Methods of test for masonry units - Determination of flatness of faces of masonry units

- - (EN 771-3:2003) -

Straightness and squareness of the arris

UNI 8942-3:1986 (retired) Clay bricks and blocks. Test methods – Determination of shape, holes and profile (in Italian) ASTM C 67:2005 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile – Measurement of Warpage

- - - -




Table 2: Requirements on the physical properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIRE-MENT

TEST METHOD



NOTES

1 2 3 4 5 6

Aspect (cracks, lumps, flaking and other defects)

UNI 8942-3:1986 (retired) Clay bricks and blocks. Test methods – Exam of the aspect (in Italian) R.D.16/09/1939, N.2233 Sound Inspection

(EN 771-1:2005) - - -

Density EN 772-13:2002 Methods of test for masonry units – Determination of net and gross dry density of masonry units (except for natural stone)

LD ≤ 1000 kg/m3 HD > 1000 kg/m3 (EN 771-1:2005)

- - -

Porosity UNI 8942-3:1986 (retired) Clay bricks and blocks. Test methods. Determination of porosity (in Italian)

- The porosity is intended as the distribution of pores volume in respect to their diameter. The porosity can affect on the freeze-thaw resistance

- -

Shrinkage - - - - -

Moisture content

EN 772-10:2001 Methods of test for masonry units – Determination of moisture content of calcium silicate and autoclaved aerated concrete units.

- - - -

Water absorption

EN 772-11:2001 Methods of test for masonry units – Determination of water absorption of aggregate concrete, manufactured stone and natural stone masonry units due to capillary action and the initial rate of water absorption of clay masonry units

For only HD units (EN 771-1:2005) (R.D. 2233/1939)

- - -

Damp absorption

- - - - -

Capillarity ASTM C 67:2005 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile – Initial Rate of Absorption (Suction)

- - - -

Water vapour Permeability

EN 772-15:2001 Methods of test for masonry units – Determination of water vapour permeability of autoclaved aerated concrete masonry units

Diffusion coefficient of water vapour µ = 5 ÷ 10 (EN 1745:2002)

- - -

Hydric expansion

- - - - -

Thermal expansion

- - - - -




Table 2: (continued) Requirements on the physical properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIRE-MENT

TEST METHOD



NOTES

1 2 3 4 5 6

Efflorescence UNI 8942-3:1986 (retired) Clay bricks and blocks. Test methods - Determination of attitude to efflorescence (in Italian) ASTM C 67 – 2005 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile – Efflorescence

(EN 771-1:2005) - - -

Thermal conductivity

- For normal clay λ ≤ 0,55 W/(m . K) For lightened clay λ= 0,20 ÷ 0,30 W/(m . K) (D.M. 02/04/1998, EN 1745:2002)

- - -

Moisture movement

EN 772-19:2000 Methods of test for masonry units. Determination of moisture expansion of large horizontally perforated clay masonry units

(EN 771-1:2005) - (EN 772-14:2003) -

Table 3: Requirements on the durability properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIREMENT

TEST METHOD

CODE REQUIRED

PERFORMANCE

NOTES CODE REQUIRED

PERFORMANCE

NOTES

1 2 3 4 5 6

Freeze-thaw resistance

EN 772-18:2001 Methods of test for masonry units - Determination of freeze-thaw resistance of calcium silicate masonry units

Only for HD: F0 passive exposure F1 moderate F2 severe (EN 771-1:2005, R.D. 2233/1939)

- - -

Soluble salts content

EN 772-5:2003 Methods of test for masonry units - Determination of the active soluble salts content of clay masonry units.

For HD units not protected (EN 771-1:2005, R.D. 2233/1939)

- - -

Reaction to fire

EN 13823:2002 Reaction to fire tests for building products - Building products excluding floorings exposed to the thermal attack by a single burning itemEN ISO 1182:2002 Reaction to fire tests for building products - Non combustibility test prEN ISO 1716:2002 Reaction to fire tests for building products - Determination of the heat of combustion ISO 11925-2:2002 Reaction to fire tests - Ignitability of building products subjected to direct impingement of flame - Single-flame source test

Euroclass A1 (EN 771-1:2005, D.10/03/2005, L.818)

EN 13501-1:2002 Classification using test data from reaction to fire tests

Euroclass A1 (EN 771-3:2003)

EN 13501-1:2002 Classification using test data from reaction to fire tests




Table 4: Requirements on the mechanical properties of the masonry units

CLAY UNIT CONCRETE UNIT REQUIRE- MENT

TEST METHOD



NOTES

1 2 3 4 5 6

Normal to the bed face: 5 N/mm2 (EN 1998-1, 2004) 5 N/mm2 (OPCM 3431)

Compressive strength

EN 772-1:2002 Methods of test for masonry units – Determina-tion of compressive strength

Parallel to the bed face in the plane of the wall: 2 N/mm2 (EN 1998-1, 2004) 1,5 N/mm2 (OPCM 3431)

Code requirements are according to the direction of bedding of the unit; the expected values are with respect to the direction of holes EC6: Normalized compressive strength OPCM: Characteristic compressive strength

- -

Elastic modulus

UNI 9730-3:1990 Clay blocks for flooring. Test methods.

- - - This standard is for hollow tiles but it is generally used for units

Flexural strength

ASTM C 67: 2005 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile – Modulus of Rupture (Flexure test)

- - - -

Tensile strength

EN 772-6:2002 Methods of test for masonry units – Determina-tion of bending tensile strength of aggregate concrete masonry units

- - - -




2.3 REQUIREMENTS ON THE MORTAR

In the following tables the requirements for masonry mortars are compiled. Thereby it is distinguished

between requirements on the physical properties of fresh and hardened mortar, the durability and the

mechanical properties of the hardened mortar. The test standards used to determine the respective

properties are mentioned. According to the definition given by the Eurocode 6 (EN 1996-1-1, 2005), the

mortar types are distinguished as general purpose, thin layer or lightweight mortar according to their

constituents. The new Standards about mortar have been written using the performance based concept.

Instead of having prescribed proportions of the materials, the performance concept allows the producer to

select freely the mix proportions in order to achieve a stated performance required by the Standards

themselves. Thus the Standards move away from the “recipe approach”. The requirements of the mortars

are accordingly described following the performance concept.

Table 5: Requirements on the physical properties of fresh and hardened mortar

REQUIREMENT TEST METHOD GENERAL PURPOSE MORTAR

LIGHT-WEIGHT MORTAR

THIN LAYER MORTAR

NOTE

1 2 3 4 5 6

Composition UNI 11189:2006 Cultural heritage - Historical and repair mortars - Test methods for chemical characterization of a mortar - Chemical analysis

Classification of mortars in respect to the compositionM4 0:0:1:3:0 M4 0:1:0:0:3 M4 1:0:2:9:0 M3 1:0:1:5:0 M2 1:0:0.5:4:0 M1 1:0:0:3:0 (D.M.20/11/1987)

- Aggregates (DIN V 20000-412:2004)

EN 1996-1-1:2005 (section 3.2.2) Constituents by volume defined as cement:lime:sand D.M. 20/11/1987 (section 1.2.1) Constituents by volume defined as cement:common lime:hydraulic lime: sand:pozzolana There is no specific test-standard for new mortars

Workability EN 1015-9:2001 Methods of test for mortar for masonry - Determination of workable life and correction time of fresh mortar.

- - Workable life at least 4 h, correction time at least 7 min (DIN V 20000-412:2004)

-

Particle size distribution

EN 1015-1:2000 Methods of test for mortar for masonry - Determination of particle size distribution (by sieve analysis)

Generally a 4 mm max diameter is used

- Max aggregate diameter: 2 mm (EN 998-2:2003) respectively 1 mm

(DIN V 20000-412:2004)

-

Bulk Density EN 1015-6:2000 Methods of test for mortar for masonry - Determination of bulk density of fresh mortar EN 1015-10:2001 Methods of test for mortar for masonry - Determination of dry bulk density of hardened mortar.

- For hardened mortar ≤ 1300 kg/m3

(EN 998-2:2003)

≥ 1500 kg/m³ (DIN V 20000-412:2004)

-

Air content EN 1015-7:2000 Methods of test for mortar for masonry - Determination of air content of fresh mortar

(EN 998-2:2003) - - -




Table 5: (continued) Requirements on the physical properties of fresh and hardened mortar

REQUIREMENT TEST METHOD GENERAL PURPOSE MORTAR

LIGHT-WEIGHT MORTAR

THIN LAYER MORTAR

NOTE

1 2 3 4 5 6

Consistence EN 1015-3:2000 Determination of consistence of fresh mortar (by flow table) EN 1015-4:2000 Methods of test for mortar for masonry - Determination of consistence of fresh mortar (by plunger penetration)

- - - -

Chloride content UNI EN 1015-17:2002 Methods of test for mortar for masonry - Determination of water-soluble chloride content of fresh mortars

Should be ≤ 0.1% in mass of mortar by dry mass (EN 998-2:2003)

Should be ≤ 0.1% in mass of mortar by dry mass (EN 998-2:2003) respectively me be ≤ 0.1% in mass of mortar by dry mass (DIN V 20000-412:2004)

-

Shrinkage* UNI 6687:1973 Cement mortar. Hydraulic shrinkage determination. Laboratory test

- - - -

Water absorption EN 1015-18:2004 Methods of test for mortar for masonry - Determination of water absorption coefficient due to capillary action of hardened mortar

- - - -

Water vapour Permeability*

EN 1015-19:2000 Methods of test for mortar for masonry - Determination of water vapour permeability of hardened rendering and plastering mortars

- - - -

Specific heat* EN 1745:2005 Masonry and masonry products - Methods for determining design thermal values

- - - -

Thermal conductivity

EN 1745:2005 Masonry and masonry products - Methods for determining design thermal values

- - - -

Thermal expansion*

EN 1745:2005 Masonry and masonry products - Methods for determining design thermal values

- - - -

Fire Reaction EN 13501-1:2002 Classification using test data from reaction to fire tests EN 13823:2002 Reaction to fire tests for building products - Building products excluding floorings exposed to the thermal attack by a single burning item EN ISO 1182:2002 Reaction to fire tests for building products - Non combustibility test prEN ISO 1716:2002 Reaction to fire tests for building products - Determination of the heat of combustion ISO 11925-2:2002 Reaction to fire tests - Ignitability of building products subjected to direct impingement of flame - Part 2: Single-flame source test

- Class A1 (DIN V 20000-412:2004)

Mortars containing a fraction of organic materials ≤1% are Class A1 of fire reaction, mortars containing a fraction of organic materials > 1% have to be classified in respect of EN 13501-1:2002 and it has to declared the suitable fire reaction Class (EN 998-2:2003)




*It seems that shrinkage and water vapour permeability are more important for plasters than for mortars.

Shrinkage is generally hindered by the geometry of units and their assemblage and the water vapour

permeability is not very relevant on the overall permeability of the masonry wall. Furthermore, as far as

mortars for masonry are concerned, probably mechanisms of shrinkage control or expansive mechanisms to

hinder the shrinkage do not yet exist. Conversely, specific heat and thermal expansion are of basic

importance to evaluate the tendency to create thermal gradients between units and mortar when masonry is

subjected to heating and subsequent cooling. The thermal gradient is directly related to the risk that cracks

open in plaster in correspondence of the mortar joint in the backside masonry.

Table 6: Requirements on the durability properties of hardened mortar

REQUIRE-MENT

TEST METHOD GENERAL PURPOSE MORTAR

LIGHT-WEIGHT MORTAR

THIN LAYER MORTAR

NOTE

1 2 3 4 5 6

Freeze-thaw resistance

UNI 7087:2002 Concrete - Determination of the resistance to the degrade due to freeze- thaw cycles

- - - This standard is for concretes but it is usually used also for mortars.

Soluble salts content

UNI 11087:2003 Natural and artificial stones - Water soluble salts determination

- - - The soluble salts content is directly related with the tendency to create salt efflorescence on mortar joints subject to wet/dry cycles, such as mortar in facing walls but also in ordinary masonry




Table 7: Requirements on the mechanical properties of hardened mortar

REQUIRE-MENT

TEST METHOD GENERAL PURPOSE MORTAR

LIGHT-WEIGHT MORTAR

THIN LAYER

MORTAR

NOTE

1 2 3 4 5 6


EN 1015-11:1999 Methods of test for mortar for masonry - Determination of flexural and compressive strength of hardened mortar

fm,min ≥ 4N/mm2 for reinforced masonry fm,min ≥ 2N/mm2 for bed joint reinforced masonry (EN1996-1-1:2005) In seismic zone fm,min ≥ 5 N/mm2 for unreinforced & confined masonry and ≥ 10N/mm2 for reinforced masonry (prEN1998-1:2003) fm,min ≥ 5N/mm2

(OPCM 3431, 2005)

- at least mortar class M15 (DIN V 20000-412:2004)

If the composition is prescribed, the compressive strength has to be declared on the basis of public reference, which establish the relation between the mixture proportions and the compressive strength (EN 998-2:2003)

Flexural EN 1015-11:1999 Methods of test for mortar for masonry - Determination of flexural and compressive strength of hardened mortar

- - - -

Initial shear strength

EN 1052-3: 2002 Determination of initial shear strength

0.10 ÷ 0.30 N/mm² for clay block 0.10 ÷ 0.20 N/mm² for concrete block

0.15 N/mm²

0.3 N/mm² 0.2 N/mm² (DIN V 20000-412:20041))

These values are not a limit, but they are an indication (EN 998-2:2003, EN 1996-1-1, 2005, D.M. 20/11/1987) 1) requirement

Adhesive tensile strength

EN 1052-5: 2005 Determination of bond strength by the bond wrench method; ASTM C952-91 Bond strength of mortar to masonry units

- - - -

Elastic modulus

UNI 6556:1976 Tests of concretes. Determination of static modulus of elasticity in compression.

- - - This standard is for concretes but it is usually used also for mortars.




2.4 PROPERTIES OF COMMONLY USED CONCRETE

The following table contains properties of concretes commonly used to fill masonry made of large hollow clay

units. Requirements on the respective concrete classes are defined in EN 206-1:2006 Concrete -

Specification, performance, production and conformity.

Table 8: Physical and mechanical properties of fresh concrete

REQUIREMENT TEST METHOD CODE REQUIRED PERFOR-MANCE

NOTE

1 2 3 4

Consistency EN 12350-3: 1999 Testing fresh concrete - Vebe test EN 12350-4: 1999 Testing fresh concrete - Degree of compactability EN 12350-5: 1999 Testing fresh concrete - Flow table test. UNI 11041:2003 Testing fresh self compacting concrete - Determination of free flow and time flow

- Consistency class F5 according to EN 206-1:2001 is usually used for hollow clay block masonry

Flowability EN 12350-2: 1999 Testing fresh concrete - Slump test. UNI 11043:2003 Testing fresh self compacting concrete - Determination of confined flowability in L-shape box UNI 11044:2003 Testing fresh self compacting concrete - Determination of confined flowability in U-shape box UNI 11045:2003 Testing fresh self compacting concrete - Determination of confined flowability in J-ring

- -

Composition UNI 6393:1988 Checking fresh concrete composition.

- -

Density EN 12350-6: 1999 Testing fresh concrete - Density.

- -

Air content EN 12350-7: 2000 Testing fresh concrete - Air content - Pressure methods.

- -

Viscosity UNI 11042:2003 Testing fresh self compacting concrete - Determination of flow time in V- funnel

- -

Bleeding UNI 7122:1989 Fresh concrete. Determination of bleeding.

- -




Table 9: Physical and mechanical properties of hardened concrete

REQUIREMENT TEST METHOD CODE REQUIRED PERFORMANCE

NOTE

1 2 3 4

Density EN 12390-7:2000 Testing hardened concrete - Density of hardened concrete

- -

Depth of penetration of water under pressure

EN 12390-8:2000 Testing hardened concrete - Depth of penetration of water under pressure

- -

Compressive strength EN 12390-3: 2001 Testing hardened concrete - Compressive strength of test specimens

D.M. 14/9/2005:

Rck≥15 N/mm2

Compressive strength class C20/25 according to EN 206-1:2001 is usually used for hollow clay block masonry

Tensile strength EN 12390-6: 2000 Testing hardened concrete - Tensile splitting strength of test specimens

- -

Flexural strength EN 12390-5: 2000 Testing hardened concrete - Flexural strength of test specimens

- -

Elastic modulus UNI 6556:1976 Tests of concretes. Determination of static modulus of elasticity in compression.

- -

Creep EN 1355:1996 Determination of creep strains under compression of autoclaved aerated concrete of lightweight aggregate concrete with open structure

- -

Shrinkage UNI 6555:1973 Concrete made with aggregate maximum size 30 mm. Hydraulic shrinkage determination. UNI 7086:1972 Concrete made with over 30 mm size aggregates. Hydraulic shrinkage determination. EN 680:2005 Determination of the drying shrinkage of autoclaved aerated concrete

- -

Pull-out EN 12504-3: 2005 Testing concrete in structures - Determination of pull-out force

- -

Carbonation UNI 9944:1992 Corrosion and protection of reinforcing steel in concrete. Determination of the carbonation depth and of the chlorides penetration profile in concrete.

- -




2.5 REQUIREMENTS ON THE REINFORCEMENT AND THE FASTENINGS

To define the requirements and the test standards for the reinforcement it is respectively distinguished

between special reinforcement for masonry as e. g. steel meshwork or trusses and simple rebars used to

reinforce the concrete infill of large hollow clay unit masonry. The test standards for these types of

reinforcement are compiled within the table 10. Table 11 contains the test standards used for fastening.

Table 10: Requirements on the mechanical properties of the reinforcement


NOTE

1 2 3 4

Tensile strength EN ISO 15630-1:2002 Steel for the reinforcement and prestressing of concrete - Test methods - Reinforcing bar, wire rod and wire

- -*

Bond strength CNR UNI 10020:1971 Beam - test on steel bars. EN 12269-1:2000 Determination of the bond behaviour between reinforcing steel and autoclaved aerated concrete by the "beam test" - Short term test EN 12269-2: 2003 Determination of the bond behaviour between reinforcing steel and autoclaved aerated concrete by the "beam test" - Long term test EN 846-2:2000 Methods of test for ancillary components for masonry –Determination of bond strength of prefabricated bed joint reinforcement in mortar joints

D.M. 14/9/2005 Ribbed (improved bond) reinforcing steel

-

Shear strength EN 846-3:2000 Methods of test for ancillary components for masonry – Determination of shear load capacity of welds of prefabricated bed joint reinforcement

- -

* In Germany the requirements on reinforcement for concrete are determined in DIN 488-1:1984, DIN 488-

2:1986 and DIN 488-4:1986

Table 11: Requirements on the mechanical properties of the fastenings


NOTE

1 2 3 4

Tensile strength EN 846-5:2000 Methods of test for ancillary components for masonry - Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couple test) EN 846-6:2000 Methods of test for ancillary components for masonry - Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)

- -


EN 846-5:2000 Methods of test for ancillary components for masonry - Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couple test) EN 846-6:2000 Methods of test for ancillary components for masonry - Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)

- -

Shear load capacity

EN 846-7:2000 Methods of tests for ancillary components for masonry - Determination of shear load capacity and load displacement characteristics of shear ties and slip ties (couple test for mortar joint connections)

- -




3 PERFORATED CLAY UNITS

3.1 REASONS FOR AND AIMS OF THE INVESTIGATIONS

In many countries facing the Mediterranean basin (Italy, Spain, Portugal, Greece, etc.) and also northern

European countries, such as Slovenia, Germany, etc., load bearing masonry walls made of perforated clay

units are largely used for the construction of residential buildings as well as larger buildings with industrial or

services destination. However, the designers are facing many problems in the calculation of these kinds of

buildings, due to the introduction of more severe seismic codes, both at European (Eurocode 8) and National

(OPCM 3431 in Italy) level. For this reason, it is necessary to explore all the possibilities of existing masonry

systems for load bearing masonry buildings, and to develop new construction systems still based on the use

of perforated clay units, in order to save traditional construction techniques and materials by innovating

them, and at the same time to avoid the shrinkage of the clay unit industrial sector which is a leading sector

in many countries, and in Italy in particular.

Within the research project DISWall, two systems made with perforated clay units are thus going to be

studied. The first one is a system similar to confined masonry, made by using a special unit for the reinforced

masonry panel and an ordinary unit for reinforced confining columns. The units have to be placed in the

masonry panel with horizontal holes, and they have to present recesses for the placement of the horizontal

reinforcement. The main advantages are that all the problems related to cover of bars and mortar shrinkage

are overcome, due to the fact that there is a special recess to place the reinforcement, it is possible to have

the un-coupling of the reinforcement, it is possible to preserve a construction technique (masonry made with

horizontal holes) which is very traditional for all the countries facing the Mediterranean basin, which also

allows reaching very good thermal and acoustic insulation.

The second construction system that is going to be studied within the research project DISWall, is a system

of reinforced masonry, made by using the perforated clay units with vertical holes, developed and aimed at

building mainly tall, load bearing reinforced masonry walls for factories, sport centres, etc., which have to

resist out-of-plane actions in particular when they are in the presence of a deformable roof. For this system,

a ‘C’ shaped unit to be used very simply with the possibility of putting it in place after the vertical

reinforcement has been already placed, and with dimensions that allow to use it in two different direction (but

still with vertical holes) will be developed. No particular improvement is foreseen for the reinforcement

element, apart for exploring the possibility, through the hole in the ‘C’ shaped unit, of un-coupling the

reinforcement. Special reinforcement elements should only be developed if necessary, for simpler and exact

installation of the reinforcement in this system.




3.2 INVOLVED PARTNERS AND PLANNED TASKS

Table 12: Involved partners, proposed tasks and restraints

INVOLVED PARTNER

PROPOSED TASKS

1 2

ALAN Masonry units: - Formulation of the application field of the masonry units with horizontal holes. - Compilation of the dimensions, geometry, manufacturing constraints, mechanical properties

for perforated clay units with horizontal holes and of the limiting constraints concerning the workability (dimensions of the recesses).

- Design and production of new units Reinforcement: - Formulation of requirements on the layout of reinforcement and fastenings for the new

construction system. Mortar: - Formulation of requirements on the flow properties to allow for a proper recess filling - Formulation of requirements for mortar with additives to improve the bond properties

CISEDIL Masonry units: - Formulation of the application field of the masonry units with vertical holes. - Formulation of new geometry for unit in order to allow reinforcement un-coupling and better

out-of-plane behaviour for the wall and of the limiting constraints concerning the workability (dimensions of the cores).

- Design and production of units Mortar: - Formulation of requirements on the flow properties, the workability, the water retention, the

mechanical properties. - Formulation of requirements (both mortar and units) to improve bond

TASSULLO Mortar/concrete: - Formulation of new mortar/concrete composition or use of additives to meet the

requirements for reinforced masonry made with perforated hollow unit - Design and production of new mortar/concrete

ANDIL Masonry units: - Formulation of requirements for masonry units




Table 12: (continued) Involved partners and proposed tasks

INVOLVED PARTNER

PROPOSED TASKS

1 2

UNIPD Masonry units: - Formulation of desired improvements of the mechanical properties and of test methods for

testing the behaviour under in-plane loads - Testing of the mechanical and physical properties - Modelling to assess the behaviour of units with horizontal holes and to formulate

improvements of the unit geometry in general Reinforcement: - Formulation of desired requirements on the amount and mechanical properties of

reinforcement and fastenings Mortar: - Formulation of desired mechanical properties and bonding strength between masonry and

masonry unit. - Testing of the mechanical and physical properties - Testing of bond between mortar and masonry units.




3.3 SELECTED APPROACH

According to section 3.1, the main task of UNIPD is the development of two reinforced masonry construction

systems based on the use of perforated clay units.

For the system based on the use of horizontally perforated clay units, first of all the properties of the

perforated clay unit are to be designed and studied, in particular the shape (geometry of the unit) in order to

allow the creation of all the needed structural details and a proper filling for the mortar that surrounds the

reinforcement, and the mechanical properties of the unit (still related not only to the material properties but

also to the shape of the unit). For this construction system, physical properties and material laws for the

components perforated clay blocks and mortar will be determined at first, by tests on the masonry

components and on small components, and will be modelled in order to find improved unit shape and

configuration:

- FE modelling of masonry units;

- Compression tests, splitting tests and special tests on masonry units;

- Compression and tensile tests on mortar;

- Shrinkage and flow tests on mortar;

- Bond tests between mortar and masonry units.

The development of the masonry construction system as a whole will be done in WP4. Testing and modeling

of structural components will be carried out in WP5. Particularly significant will be the development of design

rules (WP6), as currently the Eurocodes or other National codes do not consider special rules for the

confined masonry, but they simply treat it as unreinforced masonry.

For the system based on the use of ‘C’ shaped vertically perforated clay units, again, the properties of the

perforated clay unit are to be designed and studied, in particular for what concern the shape (geometry of the

unit) in order to allow the creation of all the needed structural details and a proper filling for the mortar that

surrounds the reinforcement and to consider the use of specific blocks for concentrated nucleuses. For this

construction system, physical properties and material laws for the components perforated clay blocks and

mortar will be determined by tests on the masonry components and on small components:

- Compression tests on masonry units;

- Compression and tensile tests on mortar;

- Shrinkage and flow tests on mortar;

- Bond tests between mortar and masonry units.

Testing and modelling of structural components will be carried out in WP5 and the development of design

rules will be done in WP6, and this will be particularly aimed at studying the out-of-plane behaviour of the

masonry system, as currently the code requirements on slenderness ratios for walls seems to be too

conservative and the approach in the design and verification of walls subjected to wind and earthquake




actions has to be improved, as well as new construction systems conceived for better out-of-plane

performances can be proposed.

3.4 CONSTRAINTS AND REQUIREMENTS FOR THE REINFORCEMENT

Constraints for the properties of the reinforcement are:

- Reinforcement has to be made only of ribbed bars (when bars are used);

- The actual available masonry reinforcement complies with EN 846-2 and 846-3 (when trusses are used).

- The products can be produced from cold drawn steel wire in diameters ranging from 3 to 5 mm with

tensile strengths up to 600 N/mm².

- The horizontal reinforcement cannot be placed with distance greater than 600 mm. The percentage of

horizontal reinforcement has to be 0,04% ≤ ρh ≤ 0,5%.

- The vertical reinforcement (at least 200 mm2) has to be placed at any wall intersection/wall edge/opening

and cannot be placed with distance greater than 4 m. The percentage of vertical reinforcement has to be

0,05% ≤ ρv ≤ 1,0%.

3.5 DESIGN OF PERFORATED CLAY MASONRY UNITS

For the reinforced masonry system made with horizontally perforated units, the units width is 30 cm (but can

vary between 35 and 20 cm) and will be mainly with square shape, in order to be used in a second time in

both direction, also for the masonry columns, without any problem. The compressive strength in the direction

orthogonal to the holes has to be at least 5 N/mm2, but even more, in order to provide adequate robustness

of the unit, to allow for a suitable behaviour when the masonry element is subjected to combined vertical and

horizontal in-plane loading. This will be provided by change in the raw material mix and also by adequate

mould design (no straight angles between shells and webs). For the ‘C’ shaped vertically perforated units the

unit width is 38 cm. The mechanical properties of the unit are less important to be developed (but still

needed to be known), as the units with vertical holes already meet the main required structural performances

of having a compressive strength in the direction of loading equal to at least 5 N/mm2. The holes for the

vertical reinforcement should have a diameter of at least 6 cm.

3.6 BEDDING/FILLING MORTAR

The mortar will cover a topic of development, in particular for what concern the properties of consistence and

plasticity, to allow for a proper joint (recess) filling for the masonry system made with horizontally perforated

clay units, and to allow for a proper vertical filling where the reinforcement is placed for the masonry system

with ‘C’ shaped vertically perforated clay units. The vertical filling could be also done with concrete, but the

use of a fluid mortar would allow the use of a single material for the entire masonry element and so it would

be much more competitive as construction technique. In any case, the developed mortar should have




strength equal to at least 10 N/mm2. It has to be underlined that the requirements for bedding mortar is 5

N/mm2, as specified by the Italian seismic code OPCM 3431, other Italian codes ask for 15 N/mm2 for the

mortar to be used for the vertical reinforcement, the Eurocode 8 asks for 10 N/mm2 indistinctly for the

bedding/filling mortar. This seems a reasonable compromise in order to allow using a single product on site.

Secondary aspects to be studied could be the possible use of fibers or other additives, in order to improve

the bond of mortar with bars and with the clay unit, as all the reinforced joints will be created on the external

part of the shells, which allow for a generally less strong bond behaviour (in the case of the masonry system

with horizontally perforated holes); in the case of masonry made with vertically perforated units the bond

between mortar and unit is also developed by means of the use of staggered units. In this case, a secondary

aspect to be eventually covered is the possibility of using lightweight mortar to preserve good thermal

properties.




4 LARGE HOLLOW CLAY UNITS


Due to the increased design actions it is necessary to develop masonry with an increased load bearing

capacity or to utilize existing load bearing capacities. For German purposes an appropriate approach is

masonry of concrete filled hollow clay units presently used in Germany. These blocks are applicable in

Germany so far by general building inspection approvals only. The hollow clay units have got large holes,

which are filled so far with mortar or flowable concrete. Inside these holes a vertical reinforcement can be

installed. Furthermore it is possible to arrange a horizontal reinforcement by introducing recesses in the

cross web of the hollow clay units.

In dependence on the respective general building inspection approval it is allowed to apply either the load

bearing capacity of the unfilled hollow clay units or the load bearing capacity of the concrete. A structural

design considering the load bearing behaviour of the bonded materials is not possible so far.

Within the research project DISWall, in the German point of view, the focus should be directed to the

aforementioned building method. This building method should be optimized and existing load bearing

capacities should be utilized by taking the bond of units and concrete into account. For this, first of all the

properties of the masonry components “hollow clay units” and “concrete” are to be improved considering, for

example, the substantial properties in the point of view of the structural designer and the fabricator. With the

hollow clay units it suggests itself to adapt among other things the geometrical and mechanical properties.

As concrete a self-compacting concrete is to be developed. On the one hand filling the hollow clay units

should be made easier and the probability of voids in the concrete infill should be reduced. On the other

hand the concrete should be adapted in its properties very well to the formulated requirements. Furthermore

special reinforcement elements should be developed, which make a simple and exact installation of the

reinforcement possible.

For the optimized building materials a calculation approach is to be compiled which allows to consider the

load bearing behaviour of the bonded materials - hollow clay units and concrete -, to be able to utilize the

existing load bearing capacity reserves. It is planned to achieve this by tests on structural components,

which will be simulated by means of the Finite-Element-Method. Within the scope of parametric studies with

the developed Finite-Element-Models sensitive factors will be characterized influencing the load bearing

behaviour. By use of non destructive testing methods the quality of workmanship on site can be analyzed

and ensured. Within this Workpackage the self-compacting concrete will be developed and the masonry

units will be improved. The selected approach is described in section 4.3.





In the following, the tasks of the partners participating within this Workpackage are described.

Table 13: Involved partners and proposed tasks

INVOLVED PARTNER

PROPOSED TASKS

1 2

UNIPOR Masonry units: - Formulation of the application field of the masonry units (Which buildings are to be

constructed with hollow clay units?). - Compilation of the dimensions and the mechanical properties (Which dimensions of the

units are of interest?). - Formulation of manufacturing constraints (e.g. which material properties of the units

material are possible, which thicknesses of the webs and the shells are possible?). - Formulation of the limiting constraints concerning the workability (e.g. which dimensions of

the cores are necessary to ensure a good workability on site?). Concrete: - Are there requirements on the density of the concrete to ensure sufficient sound

insulation? Reinforcement: - Which reinforcement is used up to now? - Formulation of requirements on the layout of reinforcement and fastenings to ensure an

improved workability (Are there reinforcement-elements required to enhance the workability? Are fastenings to be developed? How should the elements and fastenings look like?).

TUM Masonry units: - Formulation of design actions in dependence on the application field e. g. row houses,

multi storey buildings (How is the masonry typically loaded or designed respectively?) - Formulation of desired improvements of the mechanical properties (Which properties are

necessary to ensure a sufficient load bearing capacity or are to be optimized to enhance the load bearing capacity respectively?)

- Concrete: - Formulation of desired mechanical properties (Which properties are necessary to ensure a

sufficient load bearing capacity? Which properties are required to further develop the load bearing capacity? Is a fibre-reinforcement of the concrete useful to enhance the load bearing capacity of the masonry?).

- Formulation of requirements on the bonding strength between concrete and masonry unit (Is a bonding strength required?).

- Reinforcement: - Compilation of design actions for the reinforcement and fastenings. - Which amount of reinforcement are required? - Formulation of desired requirements on the mechanical properties of reinforcement and

fastenings?




Table 14: (continued) Involved partners and proposed tasks

INVOLVED PARTNER

PROPOSED TASKS

1 2

RWTH Masonry units: - Formulation of possible improvements of the mechanical and physical properties Concrete: - Formulation of requirements on the flow properties and the workability. - Formulation of requirements on the water retention. - Compilation of possible mechanical properties.





To derive possible approaches for the further development of masonry units and the concrete used for

constructions with large hollow clay units practical tests on small specimens and simulations using the Finite-

Element-Method are planned. Within the Finite-Element-Model, which will be developed, masonry unit,

concrete and the contact zone between them will be considered with different material properties. The model

will be calibrated and validated with tests on bonded specimens. The following material properties on

masonry units, specimens taken from them and on masonry units in combination with concrete will be

determined:

- Dimensions, flatness and parallelism of bed faces of whole units,

- Density and Compressive strength of whole units,

- Fracture mechanical properties of the unit material,

- Load bearing behavior under tensile stresses parallel and perpendicular to the bed joint of specimens

taken from the units,

- Load bearing behavior under compressive stresses perpendicular to the bed joint of specimens taken

from the units,

- Load bearing behavior of filled units under both, compressive and tensile stresses perpendicular and

parallel to the bed joint,

- Adhesive tensile strength between unit and concrete.

For the test a commonly used masonry unit with a width of 240 mm will be used. The concrete will be a

vibrated concrete of the strength class C20/25 and the consistency F5. The age of the concrete will mainly

be 28 days. For the concrete, the following properties will be determined:

- Stress-strain-curves under compressive stresses,

- Stress-strain-curves under tensile stresses.

Both the tests on masonry units, specimens taken from these, bonded specimens and on concrete are part

of the Workpackage 5. By conducting parametric studies using the Finite-Element-Method possible

approaches for the further development of the masonry unit will be determined. For example the mechanical

properties of the masonry unit, the bonding strength and the geometry may be varied.

To develop the self-compacting concrete, the following tests are planned:

- Slump flow test,

- Modified L-Box-test,

- V-Funnel-test,

- Blocking ring test,

- Sedimentation test,

- Viscometer-test,

- Water retention test.




4.4 CONSTRAINTS AND REQUIREMENTS FOR REINFORCEMENT, FASTENINGS, MASONRY UNITS AND CONCRETE INFILL

Constraints for the properties of reinforcement and fastenings are:

Reinforcement:

- The actual available masonry reinforcement complies with EN 846-2 and 846-3.



- The availability ranges from 30 mm to 280 mm for horizontal bed joints reinforcement.

- Finishes: hot dip galvanized, duplex coated (Zn + epoxy) and stainless steel

- The amount of reinforcement can be determined by the demand of a sufficient load bearing capacity

under in-plane bending. A rough reference value can be taken from the minimum code requirements for

reinforced concrete walls given in Eurocode 2: up to 0.2% Ac. The maximum value results from the

geometric possibilities of the application of the reinforcement.

- The amount of reinforcement should be greater than the tension strength of the corresponding concrete

cross-section area to avoid an abrupt and brittle tension failure in the tension zone of the wall. This can

also be easily avoided by the application of fibre reinforcement, where a very ductile behavior under

tension is ensured.

Fastenings:

- orthogonal masonry reinforcement with the ancillary components is available and may be adapted to the

geometry of the masonry specimens;

- the fastenings should be able to couple the deformations of the walls with the concrete slabs to avoid

rocking effects caused by a tension failure in the bed joint between slab and masonry wall. The use of the

fastenings on site has to be easy and safely to avoid mistakes in practice.

Masonry units:

The masonry units have to withstand the loadings during the erection phase, e.g. hydraulic pressure from the

concrete infill (bending capacity of the shells) or the loadings of the structure before the final compression

strength of the concrete is reached. In the final system the units should have a sufficient diagonal tension

strength being relevant for the shear loading capacity. The compression strength of the units should be high

enough (> 12 N/mm²), ideally in a range near to the compression strength of the concrete infill.

The relevant loadings on the wall system can be generally characterized as in-plane shear loadings in

combination with an eccentric compression force, i.e. in-plane bending. Also loadings perpendicular to the

wall face like wind or earth-pressure should be included. For the loadings on the structure it is important to

distinguish between row houses, where the compression stress level is generally low, and multi storey

buildings where high compression strength has to be assumed.




Concrete infill:

The concrete infill has to ensure that the interaction of the clay bricks and the concrete leads to a ductile

behaviour of the component material under the acting stresses. A sufficient bonding strength between clay

bricks and the concrete infill is deciding under long time loading effects, e.g. shrinkage and creeping of the

concrete and also the quasi permanent compression stresses, and short time loadings e.g. under seismic

loadings. The compression strength of the concrete should be in a range near to the compression strength of

the masonry units and may be limited to a C20/25. In addition also the stress-strain relationship should

ensure a maximum strain value under the maximum compression strength.




5 CONCRETE UNITS


The major challenge that has to be faced in the Portuguese construction industry is the obtainment of an

effective and attractive load bearing and non-load masonry construction system that is able to convince

contractors to use it in the standard construction. In fact, masonry is only used as non-load bearing infill,

whose behaviour may be improved by placing horizontal reinforcement and only recently bed joint

reinforcement is known to be used. This means that new masonry concrete units can probably be developed

for the purpose of obtaining a more efficient non-load bearing system and particularly a novel load bearing

system. The solutions to be studied intend to cover both needs without introducing considerable changes in

the construction techniques.

Within the scope of the DISWall project, two types of concrete hollow blocks are to be designed. The

concrete block with two vertical hollow cells (B1), quite similar to the typical blocks used in the infill, and a

block with three hollow (B2) cells especially formulated to accommodate uniformly spaced vertical

reinforcement. The non-load bearing walls solution is intended to be obtained by the introduction of

prefabricated horizontal reinforcements in mortar bed joints. No special novel reinforcements are foreseen

for this application. However, an enhancement of the non-load bearing behaviour should be provided by the

study of the appropriate anchorages from the horizontal reinforcements to the structural concrete columns

are to be performed. The comparative analysis of the performance of load bearing walls under in-plane and

particularly under out-of-plane loading would be performed by using both types of units. This solution

foresees the use of vertical and horizontal reinforcements. Again, appropriate anchorages of vertical

reinforcements to the bound concrete structural elements are to be analyzed. The constructive construction

technique is intended to be studied in order to have minimal changes concerning the traditional technique

used for unreinforced masonry walls. The optimization of the shape, geometry and formulation of concrete

admixtures for the concrete blocks is intend to be carried out by UMINHO together with unit producer, C&A

company. By practical issues, 1:2 reduced concrete blocks will be adopted. Besides the control of the

mechanics of concrete units, an assessment of the physical properties should be performed. A central issue

to be solved concerning this structural system is the obtainment of a mortar for the bed joints that

simultaneously is able to properly fill the hollow cells and vertical joints. Moreover, it is needed that stiffness

properties of mortar and concrete units are compatible. With this respect, an additional investigation about

the economical possibilities of using self-compacted micro concrete is foreseen.

Besides the standard tests for mechanical characterization of masonry materials (units and mortar) and

interfaces, particular attention should be paid to the bond strength between reinforcements and mortar.

These tests enable the obtaining of the constitutive behaviour of masonry compounds. The experimental

program includes the flowing experimental tests:

- Compressive and tensile tests of the units

- Compressive and tensile tests of mortar

- Bond strength characterization of the unit mortar interface

- Determination of the bond strength of the prefabricated reinforcements in mortar joints




The particular aspects of the constructive system will be discussed on WP4 and the experimental and

numerical evaluation of the in-plane and out-of-plane behaviour of the reinforced masonry walls is the

subject of WP5.





Table 15: Involved partners and proposed tasks

INVOLVED PARTNER

PROPOSED TASKS

1 2

C&A Masonry units: - Evaluation of the application field of the masonry concrete units - Compilation of the dimensions and the mechanical properties - Formulation of manufacturing constraints (possible properties of the units’ material). - Formulation of the limiting constraints concerning the workability (dimensions of the cores

that ensure a good workability on site). - Production of the units Concrete: - Control of the physical properties (density) of the concrete to ensure sufficient sound and

thermal insulation Reinforcement: - Survey of the available prefabricated reinforcements - Formulation of requirements on the layout of reinforcement and fastenings to ensure an

improved workability (Are there reinforcement-elements required to enhance the workability? Are fastenings to be developed? How should the elements and fastenings look like?).

UMINHO Masonry units: - Formulation of desired mechanical properties for load and non-load bearing walls - Testing of the mechanical and physical properties of concrete units Mortar: - Formulation of desired mechanical properties and bonding strength between masonry and

masonry unit. - Formulation of the appropriate physical properties to obtain a workable infill mortar to the

reinforced hollow cells - Testing of the bond strength of the unit mortar interface - Testing of the mechanical and physical properties - Testing of the bond between reinforcement and mortar Reinforcement: - Compilation of design actions for the reinforcement and fastenings. - Design of the required reinforcement





According to section 5, the main task of UMINHO is the development of a novel constructive system based

on reinforced masonry walls. The major issue related to reinforced masonry walls is the efficient placement

of vertical reinforcement, which leads that suitable masonry units and mortar have to be used. Another issue

under discussion concerns the usage of mortar embedding to fill the hollow concrete cells that avoids the

simultaneous use of grout and mortar in the construction of reinforced masonry.

This section addresses the description of the preliminary work carried out and the work that is running on the

domain of the development of masonry materials to be used in the construction of reinforced masonry walls.

5.4 CONSTRAINTS AND REQUIREMENTS FOR THE REINFORCEMENT AND THE FASTENINGS

Constraints for the properties of reinforcement and fastenings are:

Reinforcement:

- The actual available masonry reinforcement complies with EN 845 – 3 and EN 846-2 and 846-3.



- The availability ranges from 30 mm to 280 mm for horizontal bed joints reinforcement.

- Finishes: hot dip galvanized, duplex coated (Zn+ epoxy) and stainless steel

Fastenings:

- An orthogonal masonry reinforcement with the ancillary components is available and may be adapted to

the geometry of the masonry specimens.

5.5 DESIGN OF HOLLOW CONCRETE MASONRY UNITS

The design of the masonry wall specimens to be tested in the scope of the WP5 led that 1:2 reduced scaled

concrete masonry units has to be used. Figure 1 shows the two types of concrete masonry units that were

adopted. A more classic shape is obtained through the two cell blocks, CB2C, which to certain extent is

representative of the Portuguese concrete masonry units used for non structural proposals, see Figure 1a.

They are basically used as infill of the reinforced concrete frames. A foreseen possibility of placing the

vertical reinforcement is the hollow cell. The other type of concrete masonry units is composed by three

vertical hollow cells, CB3C, see Figure 1b.

This type of block allows the placing of the vertical reinforcements in the central hole or in alternative cell

constituted by the external webs. The latter possibility can simplify the constructive process if mortar is used

in the filling of the cell. Further details about the constructive solutions will be discussed in WP4. According

to EC6, the units with this geometry are classified as belonging to Group 2.




The production of the concrete blocks has been carried out by C&A. The production is normalized according

the European Standard referring to the specification to aggregate concrete masonry units (EN 771-3),

namely with respect to dimensions of the blocks and corresponding tolerances (EN 772-16), flatness of the

faces of the aggregate concrete (EN772-20), water absorption (EN 772-8), water absorption by soaking (EN

772-11), net and gross dry density of masonry units (EN 772-13) and moisture movement of aggregate (EN

772-14).

The proportion of raw materials (cement, sand, gravel) is adjusted so that the compressive strength ranges

from 20.0 to 25.0 N/mm2. An additional concern refers the maximum aggregate size, which should be

selected to attend the 1:2 scale requirements. This issue is also important in order to achieve an appropriate

texture that enables to comply with other standard requirements (dry density, water absorption).

The mechanical characterization of the concrete masonry units is intended to be presented in WP5. This

includes uniaxial compressive strength, tensile strength and modulus of elasticity in the direction of vertical

hollow cells (perpendicular direction to the bed joints).

(a)

(b)

Figure 1: Geometry of the hollow concrete blocks; (a) three cell concrete blocks, CB3c; (b) two cell

concrete blocks, CB2c (dimensions in cm)




5.6 BEDDING/FILLING MORTAR AND GROUT

Reinforced masonry is usually composed of hollow concrete/clay masonry units, and bedding mortar and

different types of reinforcement. The filling of the vertical hollow cells is usually carried out by means of grout.

In spite of the mortar and grout can be composed of the same components, the relative proportion is quite

different. Bedding mortar, composed of a mix of cement, lime and sand, is required to have enough

plasticity/workability to be spread on the webs and shells of the masonry units, providing at same time

sufficient adhesion. On the other hand, grout is required to present enough flowability that allows the proper

filling of the hollow cells. It is stressed that the performance of the reinforced masonry, and particularly as

concerns the effectiveness of the contribution of vertical reinforcements, depends essentially on the bond

conditions between infill material and the reinforcements. This is directly related with the homogeneity of the

filling material in the sense that no voids weak the bond adherence between the infill and the reinforcements.

However, the usage of same material as embedding and as infill material has the economical advantages of

simplifies considerably the constructive process.

The major challenge is, thus, to find an embedding mortar that is suitable as an infill material to be used in

the vertical hollow cells. This constitutes the main proposal at the level of material development. An

experimental study of mortars with different mixes is to be performed to find an equilibrium point, i.e., an

intermediate mix with appropriate plasticity and sufficient workability. The mortar under study will be cement-

lime based. The reference mix will be composed by Portland cement and sand. The raw materials for the

subsequent mixtures will be Portland cement, lime and sand. The workability/flowability of the different

mixtures will increase by the addition of water, see Table 16. The Mix M2 intends to be a grout with the

addition of water. In order to evaluate the reliability of using a commercial ready mortar, an additional pre-

mixed mortar is to be used, M5.

Table 16: Set of admixtures to be studied

MIX PROPOSED TASKS

1 2 M1 1:3 (reference) M2 1:0.1:3.3 M3 1:0.5:4.5 M4 1:1:6 M5 Pre-mixed mortar

The evaluation of the performance of the mortar to work as bedding and infill material is composed of three

steps:

Step1

- Determination of the properties of fresh mortar (flow test, plunger penetration, workability, water

absorption, retention of water).

Step2

- Evaluation of the workability of the mortar by preliminary construction of small wall specimens.




- Assessment of the proper filling by means of non-destructive testing – Ultrasonic tomography.

Step3

- Determination of the properties of hardened mortar (compressive and flexural strength, modulus of

elasticity, Poisson’s ratio).

- Obtainment of the bond characteristics of the unit masonry interface (tensile and shear).

- Uniaxial compressive tests on grouted and ungrouted masonry prisms.

- Preliminary assessment of the performance of the distinct types of mortar through flexural tests in

masonry beams (results will also be discussed in Workpackage 5).

- Bond tests between masonry and reinforcements (stainless steel truss reinforcement).

deliverable 3.1 report about the requirements for masonry...

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