experimental investigation of ultimate capacity of wired mesh-reinforced cementitious slabs

8/13/2019 Experimental Investigation of Ultimate Capacity of Wired Mesh-reinforced Cementitious Slabs

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Experimental investigation of ultimate capacity of wired mesh-reinforced

cementitious slabs

Hassan Mohamed Ibrahim*

Concrete Structures, Civil Engineering Dept., Faculty of Engineering, Suez Canal University, Port-Said 42523, Egypt

a r t i c l e i n f o

Article history:Received 10 March 2010

Received in revised form 19 June 2010

Accepted 19 June 2010

Keywords:

Ferrocement

Slabs

Square

Punching

Patch

Wire mesh

a b s t r a c t

Experimental tests conducted on 27 square cementitious slabs of 490

490 mm simply supported onfour edges and subjected to patch load are presented. The slabs had a clear span of 400 400 mm and

provided with a 445 445 mm closed frame of 8 mm diameter steel bar to hold the reinforcement in

place and to act as a line support. The test variables were the wire mesh volume fraction: four expanded

and two square types; slab thickness: 40, 45, 50 and 60 mm; and the patch load pattern: square and rect-

angular. The test results showed that as the volume fraction increased the punching strength of the slabs

was also increased. Adding a wire mesh to ordinary reinforcement increases significantly the punching

resistance at column stub. Moreover, as the loaded area size increases both ductility and stiffness

increases and the bridging effect due to the difference in the reinforcement ratio in orthogonal directions

was clearly noticed. More research was needed to identify the volume fraction ratio at which the mode of

failure alter from flexure to punching.

2010 Elsevier Ltd. All rights reserved.

1. Introduction

Ferrocement is suitable for low-cost roofing, pre-cast units,

man-hole covers, etc. It can be used for the construction of domes,

vaults, shells, grid surfaces and folded plates. It is a good substitute

for timber. It can be used for making furniture, doors and window

frames, shutters and partitions. It can also be used for making

water tanks, boats and silos. Ferrocement is the best alternative

to concrete and steel. The most significant contribution of ferroce-

ment is that most of the structures made of traditional materials

can also be constructed in ferrocement[1,2].

Ferrocement has been used effectively for affordable roofing

applications around the world hence at first glance it seems a via-

ble solution for rural areas in Egypt. However, it is still not replac-

ing steel and concrete to a large extent in spite of its major

advantage over reinforced concrete because many engineers are

not convinced about this material yet. Moreover, there are also

some professionals who, without a proper study, have said that fer-

rocement is not a good material. The main reason is that they com-

pare ferrocement to reinforced concrete. To adopt this material in

actual Egyptian practice and to enrichment the information and

understanding of its behavior, an experimental investigation was

performed on cementitious slabs of thickness greater than the

common thickness of ferrocement (range 1025 mm) and rein-

forced with low cost local steel wire mesh to cover some of itsbehavioral aspects under patch loading. Since punching shear fail-

ure in reinforced concrete slabs subjected to concentrated load is

brittle, evaluation of punching shear resistance of cementitious

slabs reinforced with wire mesh should also be highlighted. Punch-

ing shear has been the object of an intense experimental effort

since the 1950s. Punching failure of slabs based on experimental

results was addressed by various authors, among others: Menetrey

[3], Mansur et al. [4], Naaman et al. [5], and Aurelio Muttoni[6]

whereas experimental study of flexural behavior of ferrocement

and cementitious composite two way slabs were reported by many

investigator among them: El Debs and Naaman[7] and Shannag

et al.[8].

Since the punching capacity of cementitious slabs reinforced

with wire mesh is the main objective of this study, an experimental

investigation on 27 simply supported slabs is reported too. The

slabs were tested to failure to investigate the deformation and

strength characteristics under patch loading. The slab reinforce-

ment is either expanded steel mesh or a square mesh. Four types

of expanded steel mesh (diamond) and two types of square mesh

were used. The slabs were square of side length of 490 mm and

clear span of 400 mm. The specimens were provided with 8 mm

diameter skeletal steel bar as a square closed frame with inner side

dimension of 445 mm that should provide line support. Primary

variables investigated include also the volume fraction of rein-

forcement, the slab thickness: 40, 45, 50 and 60 mm; and the cen-

tric load pattern: square area of 80 80 mm or rectangular area of

55 360 mm.

0950-0618/$ - see front matter 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.conbuildmat.2010.06.032

* Tel.: +20 105110316; fax: +20 119187871.

E-mail address:[email protected]

Construction and Building Materials 25 (2011) 251259

Contents lists available at ScienceDirect

Construction and Building Materials

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o n b u i l d m a t
http://dx.doi.org/10.1016/j.conbuildmat.2010.06.032mailto:[email protected]://dx.doi.org/10.1016/j.conbuildmat.2010.06.032http://www.sciencedirect.com/science/journal/09500618http://www.elsevier.com/locate/conbuildmathttp://www.elsevier.com/locate/conbuildmathttp://www.sciencedirect.com/science/journal/09500618http://dx.doi.org/10.1016/j.conbuildmat.2010.06.032mailto:[email protected]://dx.doi.org/10.1016/j.conbuildmat.2010.06.032


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2. Experimental program

The experimental program consists of 27 cementitious slabs. Two of these slabs

were the control specimens and made of plain mortar. For the sake of comparison

with traditional steel, two cementitious slab specimens reinforced with 6 mm

steel bars arranged in two orthogonal directions and spaced 100 mm apart were

cast. To evaluate the effect of combining traditional steel with wire mesh reinforce-

ment on the punching shear capacity, a diamond wire mesh of diameter 1.5 mm

was added to one of those slabs. All slab specimens were tested using a universal

testing machine under monotonic loading up to failure. The slabs were square witha side length of 490 mm and thickness of 4060 mm and were reinforced with a

single layer of wire mesh placed at 10 mm from the tension side. They are identified

using three abbreviated terms: the first term represents the wire mesh reinforce-

ment type (D for diamond and S for square mesh); the second term represents

the type of loading pattern (P for square patch loaded area of 80 80 mm with disk

height of 20 mm and L for rectangular loaded area of 55 360 mm with maximum

semi cylinder disk height of 70 mm at center area and, the last term represents the

thickness of wire mesh (3.0, or 0.63 mm for square mesh, and 2.0, or 1.50, or 0.7, or

0.30 mm for diamond mesh).

2.1. Materials and mixing proportions

The mortar matrix consisted of ordinary Portland cement complying with ESS

373[9]and ECCS 203[10]and sand passing through a No. 7 sieve (2.36 mm), free

from any deleterious substances. Grading of the sand was controlled in such a way

Table 1

Sieve analysis results for the sand.

Sieve size (mm) 2.36 1.18 0.600 0.300 0.150 0.075

% Passing by weight 100 86.54 61.63 24.77 3.69 0.88

Sand grading[2] 80 0 100 50 8 5 2 5 60 1 0 30 2 1 0 N/ A

Table 2

Types of mesh reinforcement.

Mesh type Long-way

(mm)

Transverse

(mm)

% Volume fraction

(h= 40 mm)

Diamond 0.3 mm 17.5 7.5 0.12

Diamond 0.7 mm 22.5 12.5 0.18

Diamond 1.5 mm 37.5 17.5 0.60

Diamond 2.0 mm 22.5 57.5 0.60

Galvanized square

0.63 mm

10 10 0.18

Square 3.0 mm 50 50 0.70

Square 6.0 mm 100 100 1.41

400mm

490 mm

Loadingarea360x55mm

400 mm

Loading disk 360x55 mm Loading disk 80x80 mm

480mm

400mm

490 mm

Loading plate

80 x 80 x 20 mm

Fig. 1. Set-up for panel test under patch and line loads.

Types of wire mesh

480mm

360mm

40 mm lab splice

445 mm

8 mm

diameter

steel bar490 mm

Wire Mesh

Steel bars 6 mm mesh

Fig. 2. Alternatives reinforcement details of the cementitious slabs.

252 H.M. Ibrahim / Construction and Building Materials 25 (2011) 251259


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that it would confirm with the ACI 549-1R 93[2],ESS 1108[11]and ECCS 203[10].

Table 1shows the sieve analysis results of the sand. The sand and water to cement

ratios by weight were chosen to be 2 and 0.5 respectively to achieve a normal

strength with good workability.

At the time of casting, six companion cube specimens of size 70.6 70.6

70.6 mm were also cast to determine the ultimate compressive strength of ferroce-

ment mortar. Three prisms of 40 40 160 mm were cast to determine the flex-

ural tensile and compressive strengths[10]. All specimens were cured under wet

condition for 28 days and tested for compressive and flexural tensile strengths.

The average compressive cube strength was 32 MPa where prism flexural tensile

strength was 5.6 MPa.

Steel wire mesh fabrics locally produced in the form of rolls of 1 m wide and of

yield strength around 300 MPa were used. The wire mesh was tied to a framework

made from mild steel bar with a diameter of 8 mm. The reinforcement framework

was first fabricated and the wire mesh was tied to it, making a relatively strong

cage. The skeletal steel frame is not considered a structural reinforcement but to

serve as a spacer to the mesh reinforcements. The different types of wire mesh rein-

forcement used in the present work are listed in Table 2.As can be seen fromFig. 1, the tested specimens were simply supported on four

edges on a rigid steel frame. Either centric square or rectangular patch load was ap-

plied to a contact area of 80 80 mm or 55 360 mm respectively.Fig. 2shows the

details of reinforcement of the slab specimens and the different configurations of

reinforcing wire mesh.

2.2. Test procedure and instrumentation

Tested slabs were placed on a rigid steel frame as shown inFig. 3and a dial

gauge was centrally placed at the bottom face to record deflections at different

stages of loading. An opening along one of the steel frame sides was made to pro-

vide accessibility to the placement of dial gauge and to investigate cracking pro-

gress at the bottom face during testing. Either steel square plate of 20 mm thick

or cylindrical sector of projected rectangular area and maximum height of 75 mm

and was used to transfer the load from the machine to the top face of the slab.

After testing, the slab specimens were removed from the test setup and both topand bottom sides were examined to investigate the sustained damage, such as

yielding of reinforcement, punching shear failure surface and cracking pattern at

the bottom face.Fig. 3. Testing of specimens under central square patch loading.

Table 3

Test results for ultimate load, ultimate deflection and failure mode.

I.D. h

(mm)

Pu (kN) Du (mm) Failure description

Specimens without reinforcement

Slab-I 40 8.0 0.30 Two-way flexure failure (diagonal cracks)

Slab-II 40 8.4 0.25

Specimens reinforced with diamond mesh 0.30 mm volume fraction 0.12

DP-0.3 4 0 9 .1 1 .1 4 Flex ural failure in t wo way action four t riangles rup ture of mesh

DL-0.3 40 12.4 1.62 Two-way flexure failure (2 triangles and 2 trapezoidal) rupture of mesh

Specimens reinforced with square mesh 0.63 mm volume fraction 0.18

SL-0.63 50 21.4/22.4 1.7/4.93 Flexural failure in two way action (bridging effect)

SL-0.63 40 19.2 1.25 Sudden failure trapezoidal and triangular cracks at top neoprene bad

SP-0.63 4 5 1 4.6 0.79 Sudd en failure rup ture of reinforcement t wo way 4 tr iangle

SP-0.63 40 11.2 1.5 Flexural failure (diagonal cracks)


DP-0.7 4 0 1 3.4 1 .7 3 Flex ural failure in t wo way action four t riangles rup ture of mesh

DP-0.7 40 13.8 2.47

DL-0.7 40 19.8 4.66 Two-way flexure failure (2 triangles and 2 trapezoidal) rupture of mesh


DP-1 .5 5 0 2 3.8 2 .7 9 Flex ural failure rupt ure of mesh along b ot h diagonals

DP-1.5 50 22.4 2.07 Flexural failure fracture of mesh reinforcement

DP-1.5 40 22.3 3.77 Flexural failure Rupture of mesh

DL-1.5 40 38.5 2.49 Flexural failure nearly one way action

Specimens reinforced with diamond mesh 2.0 mm volume fraction 0.60DP-2.0 40 19.6 6.29 Flexural bond failure two way action

DP-2.0 40 20.5 3.97

DP-2.0 60 29.5 3.78 Flexural failure in two way action

DP-2.0 50 25.0 4.49 Punching failure no mesh rupture mesh yield

DP-2.0 50 23.8 8.2 Flexural punching failure diagonal cracks at bottom face at top face cracks around loaded area and extend

diagonally from the corner of the loaded area to the corners of the slab

DL-2.0 50 35.6 20.91 Punching failure neoprene bad used at bottom triangle and trapezoidal cracks crack lines along line load

boundary half circle cracks around load edges at top face

Specimens reinforced with square mesh 3.0 mm volume fraction 0.70

SL-3.0 40 68.4 4.35 Punching failure different shape of crack

SP-3.0 40 31.0 7.46 Punching failure rupture of mesh

SP-3.0 40 25.6 6.70 Punching failure rupture of mesh

SP-3.0 50 36.0 5.32 Punching failure yield of mesh

Specimens reinforced with 6 @ 100 mm both ways volume fraction 1.41

6 mm 50 34.5 6.19 Punching failure steel yielded

6 mm+DP-

1.5

50 45.8 4.77 Flexural punching failure cracks at slab corners

H.M. Ibrahim / Construction and Building Materials 25 (2011) 251259 253


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3. Test results and discussion

In the present work the load versus central deflection curves for

the tested slabs were used to classify the failure type. Flexural fail-

ure is considered to take place in slabs in which most of the rein-

forcement yields before punching occurs and consequently the

slabs exhibits large deflection prior to failure. The flexural failure

is characterized by a smooth decrease of the carrying load withincreasing displacement. Shear failure was defined when a sudden

decrease of the load carrying capacity after the peak load has been

reached (nearly vertical branch of the load deflection curve).

On the other hand, the cracking and failure pattern were also

used to classify the failure type. Slabs were considered to fail in

flexure in the case of observing diagonal cracks extending from

the center of the patch area. Flexural punching failure occurred

as tangential crack at the outlines of patch area, followed by diag-

onal cracks extending from that area and a nearly flat plateau of

resistance was reached. The failure progressed with the rupture

of bottom reinforcement. Punching failure was monitored in some

of the tests as the load fell suddenly and was released completely.

Table 3summarizes the peak load, displacement at peak load, and

failure mode for all test specimens.

The reference slabs I and II were tested to define the ultimateload carrying capacity of plain mortar specimens, include a skeletal

frame, in flexure under monotonic patch load. Comparing the

ultimate load and deflection at ultimate load (Figs. 4 and 5), it

was found that adding diamond mesh of volume fraction of 0.12,

slab DP-0.30 and DL-0.30, increases the ultimate load under patch

and line loads by 11% and 48% respectively, whereas the deflection

0

1

2

3

4

5

6

7

8

9

10

0.0 0.1 0.2 0.3 0.4

Deflection (mm)

Load(kN)

Rreference Slab - I - h = 40 mm

Reference Slab - II - h = 40 mm

Fig. 4. Load versus deflection at center of plain mortar slabs under patch load.

0

2

4

6

8

10

12

14

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Deflection (mm)

Load(kN)

DP-0.3 mm - h = 40 mm

DL-0.3 mm - h = 40 mm

Fig. 5. Comparison of load versus deflection response at center of slabs reinforcedwith 0.3 mm diamond mesh under patch and line loads.

Fig. 6. Failure pattern of slab DL-0.30 mm under linear loads.

Fig. 7. Specimen, DP-0.70 mm typical failure pattern under patch loads.

0

5

10

15

20

25

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Deflection (mm)

Load(kN)

DP-0.7 mm - h = 40 mm

DL-0.7 mm - h = 40 mm

DP-0.7 mm - h = 40 mm




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at ultimate load was increased by 418% and 589% respectively. It is

obvious that the effect of using wire mesh significantly increases

ductility. In both cases, flexural failure was observed as shown in

Fig. 6. Similarly, for slab DP-0.7 subjected to patch load, flexural

failure mode was also obtained as presented inFig. 7. Comparing

the results of ultimate load and deflection for 40 mm slab thickness

under square patch load for the slabs DP-0.30 (Vf = 0.12) and DP-

0.7 (Vf = 0.18) shown inFigs. 5 and 8, it was found that the ulti-mate load was increased by nearly 50% whereas the ultimate

deflection was increased by 84%. For 40 mm slab thickness under

line load, the results of ultimate load and deflection of slabs DL-

0.30 and DL-0.7 shown inFigs. 5 and 8, it was found that the ulti-

mate load and deflection were increased by nearly 60% and 288%

respectively. It is worth mention that the slabs of diamond mesh

0.7 fail in flexural pattern.

For slabs reinforced with single layer of square mesh and of the

same thickness SP-0.63 (Vf= 0.18) illustrated inFig. 9and Table 3

which tested under square patch load, the ultimate load and

deflection were decreased than those of DP-0.7 (Vf= 0.18) by 21%

and 40% respectively. Under rectangular line load the percentage

decrease was 3% and 372% respectively. The ductile nature of dia-

mond mesh over square mesh was obvious from these results. The

results of slabs reinforced with square mesh show increase in the

stiffness and reduction in ductility by increasing the slab thickness

in both loading patterns adopted in this work.

Since flexural failure mode is dominant in slabs with small per-

centage of reinforcement, increasing thickness did not alter the

failure mode as illustrated in slabs SP-0.63 of 40 and 45 mm thick-

ness. In such cases, higher slab thickness led to stiffness increase

and consequently decrease in ductility. For slabs of moderate vol-

ume fraction as slabs DP-2.0, failure mode may change from flex-

ure failure (40 mm) to flexural punching or even pure punching

failure (50 mm). The failure mode may change again to flexure fail-

ure as the thickness increase (60 mm). Therefore, changing slab

thickness is an attempt aimed to define the slab thickness that con-

trols the failure mode. Increasing volume fraction (main Steel per-

centage, i.e., dowel action) is not effective as the depth increase tochange the failure mode.

Comparing the results of ultimate load and deflection for

50 mm slab thickness under square patch load for DP-1.5

(Vf= 0.60) and DP-2.0 (Vf= 0.60) of Figs. 10 and 11, it was found

that the average ultimate load was almost the same whereas the

ultimate deflection of slab DP-2.0 was greater by almost two and

half times. For slabs of 40 mm, the difference of results between

the two meshes did not vary significantly. For line loads, the con-

clusion is similar to that of square patch load case.It was observed that slabs DP-1.5 failed in flexural mode under

square patch load whereas a punching failure mode was noticed

under rectangular line loading as shown inFigs. 12 and 13. The fail-

ure pattern of slabs DP-2.0 was flexural punching for slab thickness

50 mm under both cases of loading as shown inFigs. 14 and 15. For

slabs of 40 mm and 60 mm it was found that, the failure mode was

0

5

10

15

20

25

0.0 2.0 4.0 6.0 8.0 10.0 12.0

Deflection (mm)

Load(k

N)

SP-0.63 mm - h = 40 mm

SL-0.63 mm - h = 40 mm

SP-0.63 mm - h = 45 mm

SL-0.63 mm - h = 50 mm

Fig. 9. Comparison of load versus deflection response at center of slabs reinforcedwith 0.63 mm square mesh under patch and line loads.

0

5

10

15

20

25

30

35

40

0.0 2.0 4.0 6.0 8.0 10.0 12.0

Deflection (mm)

Load(kN)

DP-1.5 mm - h = 50 mm

DP-1.5 mm - h = 50 mm

DL-1.5 mm - h = 40 mm

DP-1.5 mm - h = 40 mm

Fig. 10. Comparison of load versus deflection response at center of slabs reinforced

with 1.5 mm diamond mesh under patch and line loads.

0

4

8

12

16

20

24

28

32

36

0.0 3.0 6.0 9.0 12.0 15.0 18.0

Deflection (mm)

Load(kN)

DP-2.0 mm - h = 40 DP-2.0 mm - h = 50

DP-2.0 mm - h = 60 DP-2.0 mm - h = 50

DP-2.0 mm - h = 40 DL-2.0 mm - h = 50




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flexure as shown in Fig. 16. The failure pattern of slab SP-3.0

(Vf= 0.70) was punching for all slab thickness tested in this work

and under both cases of loading as shown inFigs. 17 and 18.

Since flexural failure mode is dominant in slabs with small per-

centage of reinforcement, increasing thickness did not alter the

failure mode as illustrated in slabs SP-0.63 of 40 and 45 mm thick-

ness. In such cases, higher slab thickness led to stiffness increase

and consequently decrease in ductility. For slabs of moderate vol-

ume fraction as slabs DP-2.0, failure mode may change from flex-

ure failure (40 mm) to flexural punching or even pure punching

failure (50 mm). The failure mode may change again to flexure fail-

ure as the thickness increase (60 mm). Therefore, changing slab

thickness is an attempt aimed to define the slab thickness that con-

trols the failure mode. Increasing volume fraction (main Steel per-

(b) bottom face(a) top face

Fig. 12. Specimen, DP-1.5 mm, after failure.

(b) bottom face(a) top face

Fig. 13. Specimen, DL-1.5 mm, after failure.

(a) top face (b) under loading disk (c) bottom face

Fig. 14. Specimen, DP-2.0 mm h = 50 mm, after punching failure.

(a) top face (b) bottom face

Fig. 15. Specimen, DL-2.0 mm, after punching failure.



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centage, i.e., dowel action) is not effective as the depth increase to

change the failure mode.

An attempt was made to evaluate the effect of combining wire

mesh of diamond shape to ordinary reinforcing steel as a reinforce-

ment of cementitious slabs. Two slabs were reinforced with steel

bars of diameter 6 mm and spaced 100 mm in the two orthogonal

directions of the slabs. One of them was additionally reinforced

with a diamond wire mesh of volume fraction of 0.18. The results

of load versus deflection and the failure patterns of these slabs are

shown inFigs. 1921. Punching failure patterns were observed for

both slabs. The contribution of diamond mesh was noticed through

an increase of the ultimate load by 32% and a decrease in deflection

at ultimate load by 30% as shown in Table 4. The recognized in-

crease in the ultimate punching capacity was referred to the dowel

action contribution of the wire mesh. Since the two orthogonal

directions of the mesh have different geometries and structure,

their bridging effects were also different as clearly shown in load

deflection curves of slabs loaded with rectangular area, where both

the mesh directions and the loaded area were different.

(a) top face (b) bottom face (c) enlarged part showsmesh rupture

Fig. 17. Specimen, SP-3.0 mm h = 40 mm, after punching failure.

Fig. 16. Specimen, DP-2.0 mm h = 60 mm, after flexural failure.

0

10

20

30

40

50

60

70

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

Deflection (mm)

Load(kN)

SP- 3.0 - h = 40

SP-3.0 - h = 40

SL-3.0 - h = 40

SP-3.0 - h = 50

Fig. 18. Comparison of load versus deflection response at center of slabs reinforcedwith 3.0 mm square mesh under patch and line loads.

0

5

10

15

20

25

30

35

40

45

50

0.0 5.0 10.0 15.0 20.0 25.0

Deflection (mm)

Load(k

N)

D 6mm@100 mm-h=50

DP-1.5mm+D 6mm@100mm -h=50

Fig. 19. Effect of adding 1.5 mm diamond mesh to slabs reinforced with ordinary

reinforcing steel bars of6 mm @ 100 mm both ways on the load-deflectionresponse at center of the slab.



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On the other hand, a comparison between the slab reinforced

with steel bars of diameter 6 mm and other specimens of the same

thickness 50 mm was made and presented inTable 4. For diamond

meshes of the same volume fraction of 0.6%, an average ultimate

capacity of 70% was obtained. However, the ductility of wider spac-

ing mesh is nearly twice times greater than that of the narrow one.

For square mesh of volume fraction of 0.6%, the ultimate capacity

obtained by 6 mm diameter ordinary steel mesh was attained with

a loss of ductility of 14%.

4. Conclusion

The following observations and conclusions were drawn for

similar slabs to those tested in the present work:

1. Using single layer of diamond wire mesh of low volume fraction

of 0.12% leads to numerous increase of plain cementitious slabs

ductility by more than four times. On the other hand, the ulti-

mate capacity was slightly increased by more than 10% for

the cases of loading considered in the present study. Hence,

the key influence of low volume fraction diamond mesh is ded-

icated to ductility improvement. Moreover, increasing the vol-

ume fraction of diamond mesh by 50% consequently increases

the ultimate load and accompanied deflection by 50% and 84%respectively.

2. Under line rectangular loading, the ultimate load and accompa-

nied deflection for slabs reinforced with diamond mesh were

increased significantly than those tested under square patch

load by nearly 60% and 288% respectively. In some cases the

failure mode may alter from punching to a flexural pattern.

3. For specimens of similar thickness and volume fraction, slabsreinforced with square meshes exhibit a reduction of ultimate

load and deflection than those of slabs reinforced with diamond

mesh by 21% and 40% respectively. The ductile nature of dia-

mond mesh over square mesh was obvious from these results.

4. For slabs reinforced with diamond mesh of similar volume frac-

tion, the mesh of wider openings configuration, DP-2.0,

revealed a ductility increase to nearly two and half times than

that of closer openings, DP-1.5, while the ultimate load is nearly

kept equal. However, the failure mode may alter between flex-

ure and punching according to the opening size of the mesh and

the loading pattern. Contrary, slabs reinforced with square

mesh, SP-3.0, examined a punching failure for all slab thickness

and under both cases of loading.

5. Adding a diamond mesh to traditionally reinforced cementi-tious slabs did not amend its punching failure mode. Neverthe-

less, it increases the ultimate load capacity due to the dowel

action contribution of the wire mesh accompanied with a

reduction of the deflection at ultimate load. A volume fraction

of 0.18% increases the ultimate load capacity by nearly 30%

associated with a reduction of the deflection at ultimate load

by almost the same percentage.

6. Since, the two orthogonal directions of the diamond mesh have

different geometries and structures; the bridging effect is

expected to arise. This is clearly recognized from the load

deflection diagram of slabs loaded with rectangular line load,

where both mesh and loaded area were different in the two

orthogonal directions.

7. More research study is needed to identify the volume fractionratio at which the mode of failure alter between flexure and


Fig. 20. Punching failure of slab reinforced with bars 6 mm @ 100 mm.


Fig. 21. Failure of slab with bars 6 mm @ 100 mm and 1.5 mm diamond mesh.

Table 4

Wired mesh versus 6 mm ordinary steel specimens (50 mm).

Specimen designation Volume fraction Pu/Pu(6) Du/Du(6)

DP-1.5 0.60 0.69 0.45

DP-1.5 0.60 0.65 0.33

DP-2.0 0.60 0.72 0.73DP-2.0 0.60 0.69 1.32

SP-3.0 0.60 1.04 0.86

6 mm + DP-1.5 2.01 1.33 0.77



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punching with particular attention to the opening size of the

mesh and loading configuration.

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[2] ACI Committee 549-1R-88. Guide for design construction and repair offerrocement. ACI 549-1R-88 and 1R-93 manual of concrete practice, Detroit;1993.

[3] Menetrey Ph. Synthesis of punching failure in reinforced concrete. Cem ConcrCompos 2002;24:497507.

[4] Mansur MA, Ahmad I, Paramasivam P. Punching shear strength of simplysupported ferrocement slabs. J Mater Civil Eng 2001;6(13):41826.

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experimental investigation of ultimate capacity of wired mesh-reinforced cementitious slabs

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