polymer concrete

CONTENTS

Polymer concrete 1 / 16

1. ABSTRACT 2

2. CONCRETE 3

2.1. DEFINITION OF THE CONCRETE ................................................................................. 3

2.2. HISTORICAL DEVELOPMENT OF THE CONCRETE .................................................... 3

2.3. ADVANTAGES OF THE CONCRETE ............................................................................ 5

2.4. DISADVANTAGES OF THE CONCRETE ....................................................................... 6

3. POLYMERS 7

3.1. INTRODUCTION ............................................................................................................ 7

3.2. MAIN GENERIC CLASSES OF POLYMERS .................................................................. 7 3.2.1. Thermoplastics ........................................................................................................................ 7 3.2.2. Thermosets or resins ............................................................................................................... 8 3.2.3. Elastomers ............................................................................................................................... 9 3.2.4. Natural polymers ...................................................................................................................... 9

3.3. PROPERTIES OF POLYMERS .................................................................................... 10

4. POLYMER CONCRETE 11

4.1. INTRODUCTION .......................................................................................................... 11

4.2. ADVANTAGES OF POLYMER CONCRETE ................................................................ 12

4.3. DISADVANTAGES OF POLYMER CONCRETE .......................................................... 12

4.4. PROPERTIES OF POLYMER CONCRETE .................................................................. 12

5. CONCLUSION 14

1 Abstract


Nowadays, requirements to be met by construction materials include not only strength

features, but also chemical resistance, resulting from the increasing contamination of the natural

environment, leading to the need to protect and increase durability of building structures. Polymer

concrete is an innovative and modern material, which excellently complies with all the strict

requirements on durability, chemical resistance, and which, at the same time, offers high mechanical

strength.

Polymer concrete, known also as resin concrete, is a constructional composite, a variation of

concrete, in which traditional binder - cement, has been completely replaced with synthetic resins

with a hardening agent and filler: mixture of sand-and-gravel and quartz powder. Binder of polymer

concrete is crucial for improved strength in relation to ordinary concrete, and particularly for

chemical resistance. The weakest part of standard concrete - the hydraulic mineral binder was

eliminated from polymer concrete.

KEYWORDS:

Concrete, cement concrete, polymers, polymer concrete, thermoplastics, synthetic resins,

elastomers, natural polymers.

1 Concrete


2.1. DEFINITION OF THE CONCRETE

CONCRETE is manmade building material

that looks like stone after hardening. The word

''concrete'' is derived from the Latin concretus,

meaning ''to grow together''. It is a controlled fluid

mixture of sand and gravel held together with a

paste of cement and water that fills the space

among the aggregate particles and glues them

together. Hardening of this paste is based on

chemical reaction between cement and water, and

that process is called hydration. Process of

hydration depends of temperature and humidity of

the environment where concrete hardens and type

of used cement in terms of his ingredients and

fineness of his grind. Concrete can be formed into different shapes to a strong, durable and

economical construction material whose appearance can be altered in many ways to make it

decorative as well as functional. Sometimes one or more admixture is added to change some

characteristics of the concrete such as its workability, durability, and time of hardening. Because it is

a fluid mixture, concrete can be formed into almost any shape and finished with a variety textures

2.2. HISTORICAL DEVELOPMENT OF THE CONCRETE

Nonhydraulic cement concretes are the oldest used in human history. As early as around

6500 B.C., nonhydraulic cement concretes were used by the Syrians and spread through Egypt, the

Middle East, Crete, Cyprus, and ancient Greece. However, it was the Romans who refined the

mixture’s use. The nonhydraulic cements used at that time were gypsum and lime. The Romans

used a primal mix for their concrete. It consisted of small pieces of gravel and coarse sand mixed

with hot lime and water, and sometimes even animal blood.

The Romans were known to have made wide usage of concrete for building roads. It is

interesting to learn that they built some 5300 miles of roads using concrete. Concrete is a very

strong building material. Historical evidence also points out that the Romans used pozzalana, animal

fat, milk, and blood as admixtures for building concrete. To trim down shrinkage, they were known to

have used horsehair. Historical evidence shows that the Assyrians and Babylonians used clay as

the bonding material. Lime was obtained by calcining limestone with a reaction of:

Fig. 1-1: Fresh Concrete and Reinforcement

CHAPTER – 1 Concrete


1000

3 2

CCaCO CaO CO

When CaO is mixed with water, it can react with water to form:

2 2

ambient temperatureCaO H o Ca OH

and is then further reacted with CO2 to form limestone again:

2 2 3 222ambient temperatureCa OH CO H O CaCO H O

The Egyptians used gypsum mortar in construction, and the gypsum was obtained by

calcining impure gypsum with a reaction of

107 130

4 2 4 2 2

12 2 3

2

CCaSO H O CaSO H O H O

When mixed with water, half-water gypsum could turn into two-water gypsum and gain strength:

4 2 2 4 2

12 3 2 2

2

ambient temperatureCaSO H O H O CaSO H O

The Egyptians used gypsum instead of lime because it could be calcined at much lower

temperatures. As early as about 3000 B.C., the Egyptians used gypsum mortar in the construction of

the Pyramid of Cheops. However, this pyramid was looted long before archeologists knew about the

building materials used. Figure 1-2 shows a pyramid in Gaza. The Chinese also used lime mortar to

build the Great Wall in the Qin dynasty (220 B.C.) (see Figure 1-3).

A hydraulic lime was developed by the Greeks and Romans using limestone containing

argillaceous (clayey) impurities. The Greeks even used volcanic ash from the island of Santorin,

while the Romans utilized volcanic ash from the Bay of Naples to mix with lime to produce hydraulic

lime. It was found that mortar made of such hydraulic lime could resist water. Thus, hydraulic lime

mortars were used extensively for hydraulic structures from second half of the first century B.C. to the

second century A.D. However, the quality of cementing materials declined throughout the Middle

Ages. The art of burning lime was almost lost and siliceous impurities were not added. High-quality

mortars disappeared for a long period.

Fig. 1-2: The Pyramid of Cheops

Fig. 1-3: The Great Wall in China



2.3. ADVANTAGES OF THE CONCRETE

1. Economical:

Concrete is the most inexpensive and the most

readily available material in the world. The cost of

production of concrete is low compared with other

engineered construction materials.

2. Ambient temperature-hardened material:

Because cement is a low-temperature bonded

inorganic material and its reaction occurs at room

temperature, concrete can gain its strength at ambient

temperature. No high temperature is needed.

3. Ability to be cast:

Fresh concrete is flowable like a liquid and hence

can be poured into various formworks to form different

desired shapes and sizes right on a construction site.

4. Energy efficient:

Compared with steel, the energy consumption of

concrete production is low.

5. Excellent resistance to water:

Unlike wood (timber) and steel, concrete can be

hardened in water and can withstand the action of water without serious deterioration, which makes

concrete an ideal material for building structures to control, store, and transport water, such as

pipelines (Figure 1-13), dams, and submarine structures.

6. High-temperature resistance:

Concrete conducts heat slowly and

is able to store considerable quantities of

heat from the environment. Moreover, the

main hydrate that provides binding to

aggregates in concrete, calcium silicate

hydrate (C–S–H), will not be completely

dehydrated until 9100C. Thus, concrete can

withstand high temperatures much better

than wood and steel.

7. Ability to consume waste:

It has been found that many

industrial wastes can be recycled as a

substitute (replacement) for cement or

aggregate, such as fly ash, slag (GGBFS =

ground granulated blast-furnaces slag),

waste glass, and etc.

Fig. 1-12: The 0-14 Tower, Dubai

Fig. 1-13: Pipeline under construction



8. Ability to work with reinforcing steel:

Concrete has a similar value to steel for the coefficient of thermal expansion (steel 1.2 ×

10−5; concrete 1.0–1.5 × 10−5). Concrete produces a good protection to steel due to existence of

CH and other alkalis (this is for normal conditions).

9. Less maintenance required:

Under normal conditions, concrete structures do not need coating or painting as protection

for weathering, while for a steel or wooden structure, it is necessary.

2.4. DISADVANTAGES OF THE CONCRETE

1. Quasi-brittle failure mode:

Concrete is a type of quasi-brittle material with low fracture toughness. Usually, concrete has

to be used with steel bars to form so-called reinforced concrete, in which steel bars are used to carry

tension and the concrete compression loads.

2. Low tensile strength:

Concrete has different values in compression and tension strength. Its tension strength is

only about 1/10 of its compressive strength for normal-strength concrete, or lower for high-strength

concrete.

3. Low toughness (ductility):

Toughness can be evaluated by the area of a load–displacement curve. Compared to steel,

concrete has very low toughness, with a value only about 1/50 to 1/100 of that of steel, as shown in

Figure 1-15.

4. Low specific strength:

5. Formwork is needed:

6. Long curing time:

The design index for concrete strength is the 28-

day compression strength. Hence, full strength

development needs a month at ambient temperature.

7. Working with cracks:

Even for reinforced concrete structure members,

the tension side has a concrete cover to protect the steel

bars. Due to the low tensile strength, the concrete cover

cracks.

Fig. 1-14: Three failure modes of materials

Fig. 1-19: Cracks due to plastic shrinkage of concrete

3 Polymers


3.1. INTRODUCTION

Almost all biological systems are built of polymers which not only perform mechanical

functions (like wood, bone, cartilage, leather) but also contain and regulate chemical reactions (leaf,

veins, cells). People use these natural polymers, of course, and have done so for thousands of

years. But it is only in this century that they have learned how to make polymers of their own. Early

efforts (bakelite, celluloid, formaldehyde plastics) were floppy and not very strong; it is still a

characteristic of most simple synthetic polymers that their stiffness (for a given section) is much less

than that of metal or, indeed, of wood or bone. That is because wood and bone are composites: they

are really made up of stiff fibers or particles, embedded in a matrix of simple polymer.

By crystallizing, or by cross-linking, or by orienting the chains, new polymers are being made

which are as stiff as aluminium; they will quickly find their way into production. The new processing

methods can impart resistance to heat as well as to mechanical deformation, opening up new

ranges of application for polymers which have already penetrated heavily into a market which used

to be dominated by metals. No designer can afford to neglect the opportunities now offered by

polymers and composites.

3.2. MAIN GENERIC CLASSES OF POLYMERS

The main engineering polymers form the basis of a number of major industries, among them paints,

rubbers, plastics, synthetic fibres and paper. As with metals and ceramics, there is a bewilderingly

large number of polymers and the number increases every year. So we shall select a number of

“generic” polymers which typify their class; others can be understood in terms of these. The classes

of interest to us here are:

1. Thermoplastics such as polyethylene, which soften on heating,

2. Thermosets or resins such as epoxy which harden when two components (a resin and a

hardener) are heated together,

3. Elastomers or rubbers,

4. Natural polymers such as cellulose, lignin and protein, which provide the mechanical basis of

most plant and animal life.

3.2.1. Thermoplastics

Polyethylene is the commonest of the thermoplastics. They are often described as linear polymers,

that is the chains are not cross-linked (though they may branch occasionally). That is why they often

if the polymer is heated: the secondary bonds which bind the molecules to each other melt so that it

CHAPTER – 2 Polymers


flows like a viscous liquid,

allowing it to be formed.

The molecules in linear

polymers have a range of

molecular weights, and

they pack together in a

variety of configurations.

Thermoplastics are made

by adding together

(“polymerising”) sub-units

(“monomers”) to form long

chains. Many of them are

made of the unit repeated

many times. The radical R

may simply be hydrogen

(as in polyethylene), or

CH3 (polypropylene) or Cl

(polyvinylchloride). A few,

like nylon, are more

complicated.

3.2.2. Thermosets or resins

Thermosets are made by mixing two components (a resin and a hardener) which react and harden,

either at room temperature or on heating. The resulting polymer is usually heavily cross-linked, so

thermosets are sometimes described as network polymers. The cross-links form during the

polymerisation of the liquid resin and hardener, so the structure is almost always amorphous. On

reheating, the additional secondary bonds melt, and the modulus of the polymer drops; but the

cross-links prevent true melting or viscous flow so the polymer cannot be hot-worked (it turns into a

rubber). Further heating just causes it to decompose.

The generic thermosets are the epoxies and the polyesters (both widely used as matrix materials for

fibre-reinforced polymers) and the formaldehyde-based plastics (widely used for moulding and hard

surfacing). Other formaldehyde plastics, which now replace bakelite, are ureaformaldehyde (used

for electrical fittings) and melamine-formaldehyde (used for tableware).

Table. 2-1: Generic thermoplastics

Table. 2-1: Generic thermoplastics



3.2.3. Elastomers

Elastomers or rubbers are

almost-linear polymers

with occasional cross-links

in which, at room

temperature, the

secondary bonds have

already melted. The cross-

links provide the “memory”

of the material so that it

returns to its original shape

on unloading.

The common rubbers are all based on the single structure with the position R occupied by H, CH3.

3.2.4. Natural polymers

The rubber polyisoprene is a natural polymer. So, too, are cellulose and lignin, the main components of wood and straw, and so are proteins like wool or silk. We use cellulose in vast quantities as paper and (by treating it with nitric acid) we make celluloid and cellophane out of it. But the vast surplus of lignin left from wood processing, or available in straw, cannot be processed to give a useful polymer.

Table. 2-2: Generic thermosets or resins

Table. 2-3: Generic elastomers (rubbers)



3.3. PROPERTIES OF POLYMERS

Data for the properties of the generic polymers are shown in Table 2-5. But you have to be

particularly careful in selecting and using data for the properties of polymers. Specifications for

metals and alloys are defined fairly tightly; two pieces of Type 316L stainless steel from two different

manufacturers will not differ much. Not so with polymers: polyethylene made by one manufacturer

may be very different from polyethylene made by another. It is partly because all polymers contain a

spectrum of molecular lengths; slight changes in processing change this spectrum. But it is also

because details of the polymerisation change the extent of molecular branching and the degree of

crystallinity in the final product; and the properties can be further changed by mechanical processing

(which can, in varying degrees, align the molecules) and by proprietary additives.

Table. 2-4: Generic natural polymers

Table. 2-5: Properties polymers

4 Polymer concrete


4.1. INTRODUCTION

Polymer concrete is part of group of concretes that use polymers to supplement or replace

cement as a binder. The types include polymer-impregnated concrete, polymer concrete, and

polymer-Portland-cement concrete. Polymers in concrete have been overseen by ACI Committee

548 since 1971.

Main components of polymer concrete are shown on figure below:

In polymer concrete, thermosetting resins are used as the principal polymer component due

to their high thermal stability and resistance to a wide variety of chemicals. Polymer concrete is also

composed of aggregates that include silica, quartz, granite, limestone, and other high quality

material. The aggregate must be of good quality, free of dust and other debris, and dry. Failure of

these criteria can reduce the bond strength between the polymer binder and the aggregate.

Polymer concrete may be used for new construction or repairing of old concrete. The

adhesion properties of polymer concrete allow patching for both polymer and cementitious

concretes. The low permeability of polymer concrete allows it to be used in swimming pools, sewer

pipes, drainage channels, electrolytic cells for base metal recovery, and other structures that contain

liquids. It can also be used as a replacement for asphalt pavement, for higher durability and higher

strength.

Figure 4-1: Main components of polymer concrete

CHAPTER – 3 Polymer concrete


4.2. ADVANTAGES OF POLYMER CONCRETE

Advantages of polymer concrete include:

Rapid curing at ambient temperatures

High tensile, flexural, and compressive strength

Good adhesion to most surfaces

Good long-term durability with respect to freeze and thaw cycles

Low permeability to water and aggressive solutions

Good chemical resistance

Good resistance against corrosion

Lightweight

May be used in regular wood and steel formwork

May be vibrated to fill voids in forms

Allows use of regular form-release agents

Dielectric

4.3. DISADVANTAGES OF POLYMER CONCRETE

Some safety issues arise out of the use of polymer concrete. The monomers can be volatile,

combustible, and toxic. Initiators, which are used as catalysts, are combustible and harmful to

human skin. The promoters and accelerators are also dangerous. Polymer concretes also cost

significantly more than conventional concrete.

4.4. PROPERTIES OF POLYMER CONCRETE

Using resins instead of traditional

binder help us obtain a series of

interesting properties such as high

chemical resistance to many

corrosive chemical substances or

high mechanical strength. In case of

ordinary concrete, the strength

properties of cured cement paste

are at least several times lower than

the corresponding features of the mother rocks of the aggregate, and the adhesion of binder-and-

aggregate is relatively small. The situation is different in case of resin concretes: the tensile strength

of hardened resin binder is much higher, and the compressive strength is similar to the strength of

the rocks from which the aggregate was obtained. The advantages of polymer concrete are

particularly noticeable when comparing its individual properties to traditional B30 class concrete, it is

shown in table below:

CHAPTER – 3 Polymer concrete


Due to its properties, polymer concrete is nowadays used in many applications:

production of prefabricated products for bridge drainage system (bridge edge beams, bridge

kerbs, bridge drainage inlets, gutters),

production of prefabricated products for linear drainage systems (channels, linear drainage

channels, linear drainage silt boxes)

production of industrial tanks, intended for electrolysis of non-ferrous metals,

production of catch basins and channels to drain aggressive industrial wastewater, water

meter chambers, sewage pump stations,

production of storage tanks to store corrosive substances, e.g. acids, bases,

execution of chemical resistant cladding as chemical resistant coats made of laminates or

resin composites.

Figure 4-2: Polymer concrete vs B30 concrete

Figure 4-3: Physical and mechanical properties of polymer concrete

5 Conclusion


Polymer concrete has some advanteges if we compared with classical concrete, but also

there are some disadvantages in comparission to classical concrete. High performance of concrete

can be achieved by adding polymers, such as high strength, fast grow of strength, good stickiness

under certain conditions, but also big disadvantage of polymers are that they lose itself good quality

characteristics under high temperature, even under temperatures higher than 400C. Also polymers

additives are much more expensive than cement.

For using polymers there is necessary of good quality workers. In polymer concrete problems

can appear if aggregate and polymer binder are not compatible with each other, so before

production of polymere concrete it is necessary to make control experiments whic will proof good

relation between aggregate and polymer resin like binder.

Generally polymer concrete have much better mechanical properties than classical cement

concrete. It can be mentioned compressive and tensile strength, less curing time, bigger resistance

on impact and friction, high density and better insulation.

Advantages of classical concrete comparing with polymere concrete are higher modulus of

elasticity, lower coefficient of thermal expansion, deformation after creep and shrinkage are lower.

Depending on concrete example of structure and concrete envvironment where is located

structure, we should make decision which type of concrete is better to use.

REFERENCES


LITERATURES:

1. R.W.Cahn, P.Haasen, E.J.Kramer, Materials Science and Technology, A Comprehensive Treatment, Structure and Properties of Polymers, Volume 12, 1993, ISBN 3-527-26825-1

2. Michael F Ashbly, Materials Selection in Mechanical Design, Second edition, 1999, ISBN 0-7506-4357-9

3. Kenneth G. Budinski, Michael K. Budinski, Engineering Materials, Properties and Selection, Sixth edition, 1999, ISBN 0-13-904715-8

4. J. A. Charles, F. A. A. Crane, J. A. G. Furness, Selection and Use of Engineering Materials, Third edition, 1997,

ISBN 0-7506-3277-1

5. James F. Shackelford, Introduction to Materials Science for Engineers, Fourth edition, 1998, ISBN 0-13-807125-X

6. William D. Callister, Jr. , Materials Science and Engineering, An Introduction, Fourth edition, 1997, ISBN 0-471-

13459-7

7. Fuad Catovic, Nauka o Materijalima, Polimeri, Keramike i Kompoziti, 2001, ISBN 9958-604-03-5

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