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Experimental investigation on different high rich cement mortar for ferrocement application
Materials Today: Proceedings xxx (xxxx) xxx
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Experimental investigation on different high rich cement mortar for ferrocement application K. Sankar a, D. Shoba Rajkumar b a b
Department of Civil Engineering, Muthayammal Engineering College, Rasipuram, Tamil Nadu 637408, India Department of Civil Engineering, Government College of Engineering, Salem, Tamil Nadu, India
a r t i c l e
i n f o
Article history: Received 20 September 2019 Received in revised form 23 October 2019 Accepted 5 November 2019 Available online xxxx Keywords: Cementitious matrices Ferrocement Laminates Silica fume Metakaolin and WWM
a b s t r a c t Nowadays the Laboratory research became assumed to enlarge high rich cementitious matrices for casting thin ferrocement laminates perfectly fitted for structural restore retrofit. The developed high rich mortar matrices contain diverse combos of silica fume and Metakaolin, and offer a great balance among flowability and rich. The matrices evolved have a 28-days compressive rich variety from 48 to 64 MPa with an equivalent float range from 129% to 138%. The different high rich mortar turned into used in generating ferrocement jackets for cylindrical stubs look at its performance of the stubs are subjected to axial stresses. The progressive excessive rich ferrocement laminates seem to provide the considerable increase and increasing in the load carrying potential, lateral and ductility. In positions of ferrocement efficiency, the stubs enveloped with the laminates containing 2 and 4 layers of welded wire meshes (WWM), presented approximately 61% and 31% increase in axial stress respectively, with a corresponding increase in axial stress of about 33% and 71% respectively. Based on the outcomes of the present research, high rich ferrocement laminates containing a particular variety of welded wire meshes may be taken into consideration as a promising material for maintenance and recovery of concrete structures, particularly when using flowable high rich mortar with WWM complying with ferrocement specifications. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction The matrix used in ferrocement normally consists of mortar made with Portland cement, water, and combination, with a sand to cement ratio of about 1–2.5 by way of weight, and water to cement ratio of about 0.4–0.6 by weight [1]. A mineral admixture can be blended with cement for special packages. Normally, the combination includes well-graded sand passing through variety 8 sieve. Matrix in Ferrocement has 95% or more have an effect on at the conduct of the very last product [2,3]. Hence awesome care need to be exercised in choosing the constituent substances, namely cement and mixture, mixing and placing of the mortar. Recently there was a growing fashion in the direction of the usage of supplementary cementitious substances, consisting of silica fume, Metakaolin, herbal pozzolan, and blast furnace slag inside the production of composite cements due to comparatively cheap, technical and environmental advantages. Results of an ongoing studies application and previous studies [4,5] have advised that E-mail address: [email protected] (K. Sankar)
the most effective overall performance of cement mortars may be executed by way of incorporating silica fume, Metakaolin, and herbal pozzolan by using approximately 10–15% admixing stage with the aid of weight of cement. The findings of a latest study by way of Memon et al. [6] have revealed that slag-cement mortars containing various percentages of superplasticizers superior the compressive rich of excessive workability mortars by way of approximately 5–15% as compared to control mortars. A excessive power cementitious matrix meant for use in ferrocement programs need to meet several overall performance criteria, inclusive of flow ability and strength in addition to impermeability, sulfate resistance, corrosion safety and in a few instances frost sturdiness. Such overall performance is made viable through lowering porosity, in homogeneity, and micro cracks in the cement matrix and the transition quarter. This may be achieved by the use of superplasticizers, and supplementary cementing substances including silica fume, Metakaolin, herbal pozzolan, and granulated blast furnace slag. Limited facts exist in the literature [6–9], on the use of a combination of pozzolanic products for generating excessive rich and flowable matrices for casting thin Ferrocement factors.
https://doi.org/10.1016/j.matpr.2019.11.033 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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The corrosion of current concrete systems in many homelands necessitates the essential for developing the cost-powerful and extensive term restore and retrofit solutions that may be applied in exercise. A practical approach of repair have to think about, the quantity of damage, the form of the member, substances of restore, creation value, time and practicality. Several repair/retrofit strategies were used for restoring the burden carrying ability of damaged concrete structural factors. These contain strengthening beams and columns via epoxy bonding of metallic plates, external solving of high performance fiber bolstered concrete jackets, or ferrocement laminates, and bonding of fiber bolstered polymer sheets to present broken concrete. Ferro cement laminates in the shape of Welded Wire Mesh (WWM) whilst encapsulated with a nicely designed thin mortar layer can offer true opportunity and occasional-price technique in strengthening and repairing one-ofa-kind structural elements for reinforcing their load sporting capacities and ductility. Through the closing three decades, many researchers have emphasized the potential makes use of ferrocement laminates in restore and rehabilitation of concrete systems. Using ferrocement laminates in improving the load carrying potential and the ductility of columns has been investigated by way of numerous researches [10–18]. It was proven from their experimental consequences that, the use of ferrocement jackets and WWM as confinement reinforcement improves concrete rich and ductility very substantially. Recently, the application of ferrocement jackets has been prolonged to beautify the structural reaction during earthquakes. The response of Ferrocement retrofitted strengthened concrete columns to seismic loading was verified by using Rathish Kumar et al. [20] under 3 different axial load ratios. The learning confirmed that confining columns the usage of ferrocement jackets ended the high improved stiffness, high ductility, and rich and rich indulgence capability. The mode of failure can be changed from brittle shear failure to ductile flexural failure. The axial loads influence the hysteretic response of columns and the strength absorption capability. As may be indicated, the effectiveness of ferrocement laminates is exceedingly dependent on designing a composite cloth that possesses excessive rich, massive ductility, durable sturdiness and the use of WWMs that conform to the ferrocement specifications, at a minimum value. The goal of this investigation is to increase excessive rich and flowable matrix containing a suitable combination of silica fume, Metakaolin, and superplasticizer, to be used in skinny ferrocement laminates which are implemented for structural restore and strengthening applications. In addition, the performance of the advanced high power mortar with WWMs is investigated when used as ferrocement jackets in confining cylindrical stubs. 2. Experimental work The Experimental investigation on high rich mortar includes the components and practice of the mortar mixes along with the investigation of different mixes with their cubic compressive strengths. 2.1. Materials The materials utilized in preparing widespread mortar cubes consist of locally to be had ordinary Portland cement (ASTM Type I) with a particular gravity of (3.15), herbal silica sand with a particular gravity of (2.60) and a fineness modulus of (1.65), silica fume and Metakaolin have been in powder form with a particular gravity of 2 and a pair of 3 respectively, superplasticizer of a melamine formaldehyde sulfonated superplasticizer kind with a particular gravity of 1.21, and faucet water. The superplasticizer became included in all mixes to preserve the identical diploma of workability.
2.2. Mix proportions, blending and casting The laboratory software performed centered on four simple mixes wherein water to cement ratio, silica fume, Metakaolin and superplasticizer contents were various. The proportions of the mortar mixes solid in this research are presented in Table 1. The mortar mixes have been prepared following ASTM C 305 [21] manner the usage of a Hobart kind laboratory mixer and prolonged mixing time, to break as a great deal as feasible the Metakaolin and silica fume clumps that has a tendency to occur in the dry cloth, and to achieve a flowable aggregate. The series of mixing became to feature 75% of blending water, 50% of superplasticizer, a mix of cement, silica fume, and Metakaolin, followed by including regularly silica sand and the closing quantity of superplasticizer and water. The mortar mixes had been poured and compacted in 50 mm cubes in accordance with an ASTM C 109 manner [21]. 2.3. Consistency The consistency of mortars is expressed as a mortar float, determined in accordance to the tactics of ASTM C 230 [21]. It is compacted in mildew in the shape of a truncated cone. The cone is positioned on a drift table whose top can be raised and dropped thru a positive height by using a rotating cam. The mildew is removed from the mortar, and the desk is dropped 25 times in 15 s. The waft is measured as the resulting growth inside the average base diameter of the mortar mass, measured as a percentage of the authentic diameter. 2.4. Curing and testing After casting, the cubes were protected with moist burlap and saved inside the laboratory at 23 °C and 65% relative humidity for 24 and then demoded and placed in water. Each dice was labeled as to the date of casting, blend used and serial quantity. The cubes had been then taken out of water an afternoon before checking out and dried in air. The cubes had been tested under uniaxial compression using 1800 KN capacity Forney testing machine.
3. Result and discussion They have proven that growing high rich and achievable cement mortar incorporating various proportions of silica fume, Metakaolin, and superplasticizer via weight of cement appears to be viable. The mixes evolved taken a 28 days compressive power range from 48 to 64 MPa, with an equivalent waft range from 129% to 138%. It is thrilling to examine that the combination containing a mixture of approximately 10% silica fume, 10% Metakaolin, and 3% superplasticizer at a water to cement ratio of 0.4 on weight foundation, exhibited 15% increase in compressive rich in comparison to control mixes without admixtures as shown in Table 2. It needs to be noted that the boom in rich of the mixes containing silica fume and Metakaolin is probably the end result of a combined filler and pozzolanic effects. The filler impact results in discount in porosity of the transition zone and affords a dense microstructure and as a result will increase the strength of the combination. The pozzolanic effect facilitates inside the formation of bonds among the densely packed debris within the transition region thru the pozzolanic reaction with the calcium hydroxide liber Acted at some stage in the hydration of Portland cement to shape greater binding calcium silicates hydrates, which leads to in addition boom in rich. The improvement in the workability of the same mixes is specifically attributed to the round form of the Metakaolin debris at the micro-structural degree.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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K. Sankar, D. Shoba Rajkumar / Materials Today: Proceedings xxx (xxxx) xxx Table 1 Proportions of mortar mixes (by weight of cement). Mix ratio
Cement
Silica sand
Silica fume
Metakaolin
Water
Superplasticizer (%)
1-1 1-2 1-3 1-4 2-1 2-2 2-3 2-4 3-1 3-2 3-3 3-4 4-1 4-2 4-3 4-4
1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00
0.00 0.05 0.10 0.15 0.00 0.05 0.10 0.15 0.15 0.15 0.15 0.15 0.15 0.10 0.10 0.10
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.10 0.15 0.00 0.05
0.50 0.50 0.50 0.50 0.50 0.50 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40
0.50 1.06 1.50 2.00 1.56 1.69 2.70 3.62 3.67 3.76 4.78 2.70 3.62 3.62 3.76 4.00
Table 2 Compressive strength test results and flow values of mortar mixes. Mix no.
Compressive strength (MPa)
Flow (%)
7 days
1-1
1-2
1-3
1-4
2-1
2-2
2-3
2-4
3-1
3-2
3-3
3-4 4-1
4-2
4-3
4-4
28 days
Replicate
Avg (MPa)
Replicate
Avg (MPa)
30.9 32.6 33.5 34.1 36.2 32.9 38.3 38.9 36.2 31.5 32.6 33.5 33.7 34.7 39.0 41.5 46.5 46.5 44.6 41.1 47.4 51.8 49.7 50.1 51.3 51.7 48.7 40.7 44.7 44.0 43.7 44.7 49.0 34.7 39.0 40.7 44.7 44.0 43.7 44.7 49.0 44.6 41.1 47.4 34.7 39.0 40.7
32.3
46.7 46.3 50.3 49.9 46.8 46.1 51.8 49.9 51.2 51.7 46.3 50.3 51.9 55.5 55.8 54.1 54.5 54.4 54.2 55.3 57.2 63.0 63.4 65.1 63.7 64.9 62.8 51.9 55.5 55.8 59.9 57.5 55.8 55.5 55.8 51.9 55.5 55.8 59.9 57.5 55.8 63.7 64.9 62.8 53.3 53.4 54.4
47.8
131
47.6
129
50.9
131
52.0
130
54.4
133
54.4
129
55.5
130
63.8
131
63.8
130
54.4
133
54.46
133
51.3
136
54.4
134
56.0
134
63.8
132
52.3
138
34.4
37.8
33.7
35.8
43.5
44.4
50.5
50.5
44.4
35.8
34.3 46.4
45.5
44.4
41.0
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compressive strength in MPa
compressive Strength in MPa
60 50 40 30
7 days
20
28 days
10 0 1
2
3
4
age of curing
60 50 40 30
7 days
20
28 days
10 0 1
Fig. 1. Mixture of 1-1 to 1-4 (7 days and 28 days).
2
3
4
Compresive strength in Mpa
age of curing 60
Fig. 4. Mixture of 4-1 to 4-4 (7 days and 28 days).
50 40
Table 3 Details of tested cylindrical stubs.
30
7 days
20
28 days
10 0 1
2
3
Number of specimens
Number of WWM layers
WWM volume fraction (%)
2 2 2
0 2 4
0.0 1.1 2.2
4
age of curing 3.2. Preparation of plain concrete cylindrical stubs
compressive strength in MPa
Fig. 2. Mixture of 2-1 to 2-4 (7 days and 28 days).
70 60 50 40 30
7 days
20
28 days
10 0 1
2
3
age of curing
4
The undeniable concrete cylindrical stubs had been prepared the use of a normal concrete mix with a 28-day compressive rich of 25 MPa and stoop of 70–100 mm. The substances utilized in getting ready the concrete blend consist of regular Portland cement (ASTM Type I), crushed limestone coarse aggregate with a most length of 10 mm, an absorption potential of one. Fifty five, an oven dry bulk unique gravity of 2.60, a aggregate of washed sand and natural silica sand with an absorption capacity of 1.5% and 0.1% respectively, and an oven dry bulk precise gravity of 2.56 and a pair of 3.52 respectively, and faucet water. The concrete mix used consists of 300 kg/m3 Portland cement, 700 kg/m3 beaten limestone, 600 kg/m3 washed sand, 450 kg/m3 silica sand, and 195 kg/m3 unfastened water. The concrete mix was organized the use of a tilting drum mixer of 0.05 m3 ability. After casting, the stubs has been covered with wet burlap and saved within the laboratory at 23 °C and 65% relative humidity after which demoded and placed beneath water. After 28 days of curing, all stubs as kept in a wet environment until the date of casting the ferrocement jackets.
Fig. 3. Mixture of 3-1 to 3-4 (7 days and 28 days).
The Figs. 1–4 are Compressive strength versus age of curing for mortar mixes of 1-1, 1-2, 1-3, 1-4, 2-1, 2-2, 2-3, 2-4, 3-1, 3-2, 3-3, 3-4 and 4-1, 4-2, 4-3, 4-4 for 7 days and 28 days respectively. 3.1. Strengthening plain concrete cylindrical stubs The 2nd section of the examine become to analyze the overall performance of the developed high rich mortar mixes while used in ferrocement jackets to restrict cylindrical simple concrete stubs of 150 mm diameter and 300 mm height, below axial stresses. Table 3 indicates the information of tested stubs. Mortar mix 4-3, turned into selected for the second one segment of this investigation, due to the enhanced performance of the mortar mixes containing silica fume and Metakaolin [5,8].
3.3. Ferro cement jacket preparations The stubs have been sand-blasted to roughen their surface for a higher bond between the concrete floor and the implemented mortar layer. The WWMs used have 12.6 mm rectangular spacing and 0. 94 mm diameters, with yield rich of 385 MPa. The procedure of wrapping the WWM around the stub includes attaching the threshold of the twine mesh to the surface of the stub the use of a high adhesive bonding paste referred to as Sikadur-31; wrapping the desired number of layers across the floor, and providing an overlap of 10 mm at last layer. The joints of the mesh had been secured at one of kind locations collectively the use of double skinny metal wires which can be usually utilized in tying reinforcing bars. The mortar blend used for making ready the ferrocement jackets in this research had a 28 days compressive rich of about
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Fig. 5. Preparation of ferrocement jackets for cylindrical stubs.
Fig. 6. Axial load displacement curves for tested stubs.
63 MPa, and a float of 132%. (Mix 4-3, Table 2). All stubs wrapped with WWM had been first positioned in specifically designed molds that offer a 20 mm thick area around the stubs. To ensure that the ferrocement jackets most effective offer lateral confinement to the cylindrical stubs and now not contributing in growing its axial capability, the jackets were ended earlier than the stubs’ ends by 10 mm to prevent any direct axial load at the external ferrocement jacket in the course of test. Secondly the molds together with the stubs had been positioned at the pinnacle of a vibrating table, observed by pouring the mortar matrix and vibrated at low velocity for a period of 15 s, to reap complete penetration and consequently make certain that the mortar matrix encapsulates the WWM completely. The stubs had been remolded after 2 days and has been protected with wet burlap for as a minimum 14 days till testing (Figs. 5–9). 3.4. Preparation for testing and instrumentation The stubs have been organized for trying out via capping their top floor with a skinny gypsum layer to insure parallel surface and to distribute the load uniformly so one can reduce any eccentricity. The finished view of the stub after making use of the ferro-
cement jacket is proven in Fig. 1b. Axial displacements had been measured by way of using vertical linear variable differential transducers (LVDTs) of one hundred mm variety, mounted at 180 apart across the stub surface, in addition to any other two vertical LVDTs set up at one hundred eighty attached to the top of the gadget and the weight cell to measure the overall displacement and axial strain of the stub. The lateral displacements of the stubs were measured by the usage of horizontal LVDTs of the equal range established at a hundred and eighty apart attached to the floor of the stub; similarly to two outside horizontal stress gages to measure the stress at the jacket surface. The wire for stress gauges, the weight mobile, and the LVDT’s had been attached to facts acquisition system and checked for readings. The take a look at became performed the use of a hydraulic testing gadget with capability of 2000 KN and equipped with a shifting piston that exerts a downward axial pressure to test the stubs beneath pure axial compression. 3.5. Discussion of test consequences The resulted load-axial displacement curves of all examined stubs. It can be observed that the conduct of cylindrical stubs with
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Fig. 7. Axial stress and strain displacement curves.
Fig. 8. Axial load lateral displacement curves for cylindrical specimen.
Fig. 9. Typical failure mode for a control and jacketed cylindrical stubs.
ferrocement jackets either with or four layers of WWM are higher than the ones of manage stubs. The jacketed stubs’ curves have better load capacity at better axial traces as compared to the control stubs. For 4-layer ferrocement jackets the axial pressure reached up to 0.0035. In addition, slightly higher axial stiffness may be located in case of stubs with 4-layers WWM, due to the fact
of the lateral confinement provided by using the ferrocement jackets. The lateral displacement of all tested stubs at its mid peak had been plotted against the axial load. It may be referred to that the lateral displacement at most load are higher for jacketed stubs compared to the manage ones. Such better lateral displacements in jacketed stubs are attributed to the propagation and widening
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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K. Sankar, D. Shoba Rajkumar / Materials Today: Proceedings xxx (xxxx) xxx Table 4 Summary of test results of cylindrical stub.
Control specimens
Specimens with 2 layers of WWM
Percentage increase for 2 layers of WWM Specimens with 4 layers of WWM
Percentage increase for 4 layers of WWM
1 2 Average 1 2 Average 1 2 Average
Peak axial stress (MPa)
Maximum axial strain
Maximum lateral displacement (mm)
35.0 38.0 36.5 43.0 41.0 42.32 15.9% 46.0 42.0 45.93 28.6%
0.00208 0.00211 0.00209 0.00272 0.00261 0.00275 31.6% 0.0362 0.0302 0.00356 70.3%
0.090 0.101 0.1005 0.1307 0.1302 0.1305 30.0% 0.3145 0.2145 0.264 163.0%
of the vertical cracks which can be related by way of yielding of the WWM, while sustaining its most axial load. Results of all examined stubs with their averages are given in Table 4, in terms of the most axial stress, most axial pressure and lateral displacement at most load. Results indicate that about sixteen% growth in axial load capacity that is related with approximately 32% boom in axial strain and 30% growth in lateral displacement were recorded for stubs wrapped with 2 layers of WWM Ferrocement jackets. While such probabilities growth for the stubs with four layers WWM to be approximately 29% increase in axial stress, 70% growth in axial pressure and approximately 163% growth in lateral displacement. The growth in stub’s lateral displacement turned into mainly attributed to the widening of the vertical cracks as the WWM is laid low with yielding. It is really worth citing that the increase in axial stress and axial traces had been nearly most effective due to the confinement presented by way of the Ferrocement jacket, since the jackets were no longer attaining the ends of the stubs. The standard conduct during check and the failure approach certainly determines that the oblique wires were subjected to hoop anxiety and thereby, creating passive captivity stress. The results as shown in Table 4.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] [2] [3] [4]
[5] [6] [7] [8] [9] [10]
4. Conclusion Based at the take a look at consequences of this investigation the subsequent conclusions can be drawn: 1. Greatest power mortar matrices having various combos of silica fume and Metakaolin, and addition of right percent of superplasticizer, can provide an excessive stability between flowability and rich. The matrices advanced had a 28 days compressive power range from forty eight to 64 MPa with an agreeing flow range from 129% to 138%. Among the matrices developed the ones that contained 15% silica fume or a combination of 10% silica fume and 10% Metakaolin via weight of cement, and approximately 3% superplasticizer, performed the best overall performance and hence can be used for generating high strength ferrocement laminates appropriate for structural repair/retrofit of concrete elements. 2. Considering the kind of specimens and parameters investigated, test outcomes indicated that wrapping cylinders of 150 mm diameter and 300 mm height, with 2 layers of WWM ferrocement jackets confirmed about 16% growth in axial load potential that is associated with approximately 32% growth in axial pressure and 30% growth in lateral displacement. Whereas, such probabilities boom for the stubs wrapped with 4 layers of WWM that showed approximately 29% boom in axial stress, 70% boom in axial stress and approximately 163% boom in lateral displacement.
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Further reading [19] P. Rathish Kumar, T. Oshima, S. Mikami, T. Yamazaki, Seismic retrofit of rectangular reinforced concrete piers with the aid of ferrocement jacketing. Structure and Infrastructure Engineering-Preservation, Control, Lifestylescycle, Layout and Performance, vol. Four, Taylor and Francis Institution Ltd., 2005. pp. 253–562.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Experimental investigation on different high rich cement mortar for ferrocement application K. Sankar a, D. Shoba Rajkumar b a b
Department of Civil Engineering, Muthayammal Engineering College, Rasipuram, Tamil Nadu 637408, India Department of Civil Engineering, Government College of Engineering, Salem, Tamil Nadu, India
a r t i c l e
i n f o
Article history: Received 20 September 2019 Received in revised form 23 October 2019 Accepted 5 November 2019 Available online xxxx Keywords: Cementitious matrices Ferrocement Laminates Silica fume Metakaolin and WWM
a b s t r a c t Nowadays the Laboratory research became assumed to enlarge high rich cementitious matrices for casting thin ferrocement laminates perfectly fitted for structural restore retrofit. The developed high rich mortar matrices contain diverse combos of silica fume and Metakaolin, and offer a great balance among flowability and rich. The matrices evolved have a 28-days compressive rich variety from 48 to 64 MPa with an equivalent float range from 129% to 138%. The different high rich mortar turned into used in generating ferrocement jackets for cylindrical stubs look at its performance of the stubs are subjected to axial stresses. The progressive excessive rich ferrocement laminates seem to provide the considerable increase and increasing in the load carrying potential, lateral and ductility. In positions of ferrocement efficiency, the stubs enveloped with the laminates containing 2 and 4 layers of welded wire meshes (WWM), presented approximately 61% and 31% increase in axial stress respectively, with a corresponding increase in axial stress of about 33% and 71% respectively. Based on the outcomes of the present research, high rich ferrocement laminates containing a particular variety of welded wire meshes may be taken into consideration as a promising material for maintenance and recovery of concrete structures, particularly when using flowable high rich mortar with WWM complying with ferrocement specifications. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction The matrix used in ferrocement normally consists of mortar made with Portland cement, water, and combination, with a sand to cement ratio of about 1–2.5 by way of weight, and water to cement ratio of about 0.4–0.6 by weight [1]. A mineral admixture can be blended with cement for special packages. Normally, the combination includes well-graded sand passing through variety 8 sieve. Matrix in Ferrocement has 95% or more have an effect on at the conduct of the very last product [2,3]. Hence awesome care need to be exercised in choosing the constituent substances, namely cement and mixture, mixing and placing of the mortar. Recently there was a growing fashion in the direction of the usage of supplementary cementitious substances, consisting of silica fume, Metakaolin, herbal pozzolan, and blast furnace slag inside the production of composite cements due to comparatively cheap, technical and environmental advantages. Results of an ongoing studies application and previous studies [4,5] have advised that E-mail address: [email protected] (K. Sankar)
the most effective overall performance of cement mortars may be executed by way of incorporating silica fume, Metakaolin, and herbal pozzolan by using approximately 10–15% admixing stage with the aid of weight of cement. The findings of a latest study by way of Memon et al. [6] have revealed that slag-cement mortars containing various percentages of superplasticizers superior the compressive rich of excessive workability mortars by way of approximately 5–15% as compared to control mortars. A excessive power cementitious matrix meant for use in ferrocement programs need to meet several overall performance criteria, inclusive of flow ability and strength in addition to impermeability, sulfate resistance, corrosion safety and in a few instances frost sturdiness. Such overall performance is made viable through lowering porosity, in homogeneity, and micro cracks in the cement matrix and the transition quarter. This may be achieved by the use of superplasticizers, and supplementary cementing substances including silica fume, Metakaolin, herbal pozzolan, and granulated blast furnace slag. Limited facts exist in the literature [6–9], on the use of a combination of pozzolanic products for generating excessive rich and flowable matrices for casting thin Ferrocement factors.
https://doi.org/10.1016/j.matpr.2019.11.033 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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The corrosion of current concrete systems in many homelands necessitates the essential for developing the cost-powerful and extensive term restore and retrofit solutions that may be applied in exercise. A practical approach of repair have to think about, the quantity of damage, the form of the member, substances of restore, creation value, time and practicality. Several repair/retrofit strategies were used for restoring the burden carrying ability of damaged concrete structural factors. These contain strengthening beams and columns via epoxy bonding of metallic plates, external solving of high performance fiber bolstered concrete jackets, or ferrocement laminates, and bonding of fiber bolstered polymer sheets to present broken concrete. Ferro cement laminates in the shape of Welded Wire Mesh (WWM) whilst encapsulated with a nicely designed thin mortar layer can offer true opportunity and occasional-price technique in strengthening and repairing one-ofa-kind structural elements for reinforcing their load sporting capacities and ductility. Through the closing three decades, many researchers have emphasized the potential makes use of ferrocement laminates in restore and rehabilitation of concrete systems. Using ferrocement laminates in improving the load carrying potential and the ductility of columns has been investigated by way of numerous researches [10–18]. It was proven from their experimental consequences that, the use of ferrocement jackets and WWM as confinement reinforcement improves concrete rich and ductility very substantially. Recently, the application of ferrocement jackets has been prolonged to beautify the structural reaction during earthquakes. The response of Ferrocement retrofitted strengthened concrete columns to seismic loading was verified by using Rathish Kumar et al. [20] under 3 different axial load ratios. The learning confirmed that confining columns the usage of ferrocement jackets ended the high improved stiffness, high ductility, and rich and rich indulgence capability. The mode of failure can be changed from brittle shear failure to ductile flexural failure. The axial loads influence the hysteretic response of columns and the strength absorption capability. As may be indicated, the effectiveness of ferrocement laminates is exceedingly dependent on designing a composite cloth that possesses excessive rich, massive ductility, durable sturdiness and the use of WWMs that conform to the ferrocement specifications, at a minimum value. The goal of this investigation is to increase excessive rich and flowable matrix containing a suitable combination of silica fume, Metakaolin, and superplasticizer, to be used in skinny ferrocement laminates which are implemented for structural restore and strengthening applications. In addition, the performance of the advanced high power mortar with WWMs is investigated when used as ferrocement jackets in confining cylindrical stubs. 2. Experimental work The Experimental investigation on high rich mortar includes the components and practice of the mortar mixes along with the investigation of different mixes with their cubic compressive strengths. 2.1. Materials The materials utilized in preparing widespread mortar cubes consist of locally to be had ordinary Portland cement (ASTM Type I) with a particular gravity of (3.15), herbal silica sand with a particular gravity of (2.60) and a fineness modulus of (1.65), silica fume and Metakaolin have been in powder form with a particular gravity of 2 and a pair of 3 respectively, superplasticizer of a melamine formaldehyde sulfonated superplasticizer kind with a particular gravity of 1.21, and faucet water. The superplasticizer became included in all mixes to preserve the identical diploma of workability.
2.2. Mix proportions, blending and casting The laboratory software performed centered on four simple mixes wherein water to cement ratio, silica fume, Metakaolin and superplasticizer contents were various. The proportions of the mortar mixes solid in this research are presented in Table 1. The mortar mixes have been prepared following ASTM C 305 [21] manner the usage of a Hobart kind laboratory mixer and prolonged mixing time, to break as a great deal as feasible the Metakaolin and silica fume clumps that has a tendency to occur in the dry cloth, and to achieve a flowable aggregate. The series of mixing became to feature 75% of blending water, 50% of superplasticizer, a mix of cement, silica fume, and Metakaolin, followed by including regularly silica sand and the closing quantity of superplasticizer and water. The mortar mixes had been poured and compacted in 50 mm cubes in accordance with an ASTM C 109 manner [21]. 2.3. Consistency The consistency of mortars is expressed as a mortar float, determined in accordance to the tactics of ASTM C 230 [21]. It is compacted in mildew in the shape of a truncated cone. The cone is positioned on a drift table whose top can be raised and dropped thru a positive height by using a rotating cam. The mildew is removed from the mortar, and the desk is dropped 25 times in 15 s. The waft is measured as the resulting growth inside the average base diameter of the mortar mass, measured as a percentage of the authentic diameter. 2.4. Curing and testing After casting, the cubes were protected with moist burlap and saved inside the laboratory at 23 °C and 65% relative humidity for 24 and then demoded and placed in water. Each dice was labeled as to the date of casting, blend used and serial quantity. The cubes had been then taken out of water an afternoon before checking out and dried in air. The cubes had been tested under uniaxial compression using 1800 KN capacity Forney testing machine.
3. Result and discussion They have proven that growing high rich and achievable cement mortar incorporating various proportions of silica fume, Metakaolin, and superplasticizer via weight of cement appears to be viable. The mixes evolved taken a 28 days compressive power range from 48 to 64 MPa, with an equivalent waft range from 129% to 138%. It is thrilling to examine that the combination containing a mixture of approximately 10% silica fume, 10% Metakaolin, and 3% superplasticizer at a water to cement ratio of 0.4 on weight foundation, exhibited 15% increase in compressive rich in comparison to control mixes without admixtures as shown in Table 2. It needs to be noted that the boom in rich of the mixes containing silica fume and Metakaolin is probably the end result of a combined filler and pozzolanic effects. The filler impact results in discount in porosity of the transition zone and affords a dense microstructure and as a result will increase the strength of the combination. The pozzolanic effect facilitates inside the formation of bonds among the densely packed debris within the transition region thru the pozzolanic reaction with the calcium hydroxide liber Acted at some stage in the hydration of Portland cement to shape greater binding calcium silicates hydrates, which leads to in addition boom in rich. The improvement in the workability of the same mixes is specifically attributed to the round form of the Metakaolin debris at the micro-structural degree.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033
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K. Sankar, D. Shoba Rajkumar / Materials Today: Proceedings xxx (xxxx) xxx Table 1 Proportions of mortar mixes (by weight of cement). Mix ratio
Cement
Silica sand
Silica fume
Metakaolin
Water
Superplasticizer (%)
1-1 1-2 1-3 1-4 2-1 2-2 2-3 2-4 3-1 3-2 3-3 3-4 4-1 4-2 4-3 4-4
1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00
0.00 0.05 0.10 0.15 0.00 0.05 0.10 0.15 0.15 0.15 0.15 0.15 0.15 0.10 0.10 0.10
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.10 0.15 0.00 0.05
0.50 0.50 0.50 0.50 0.50 0.50 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40
0.50 1.06 1.50 2.00 1.56 1.69 2.70 3.62 3.67 3.76 4.78 2.70 3.62 3.62 3.76 4.00
Table 2 Compressive strength test results and flow values of mortar mixes. Mix no.
Compressive strength (MPa)
Flow (%)
7 days
1-1
1-2
1-3
1-4
2-1
2-2
2-3
2-4
3-1
3-2
3-3
3-4 4-1
4-2
4-3
4-4
28 days
Replicate
Avg (MPa)
Replicate
Avg (MPa)
30.9 32.6 33.5 34.1 36.2 32.9 38.3 38.9 36.2 31.5 32.6 33.5 33.7 34.7 39.0 41.5 46.5 46.5 44.6 41.1 47.4 51.8 49.7 50.1 51.3 51.7 48.7 40.7 44.7 44.0 43.7 44.7 49.0 34.7 39.0 40.7 44.7 44.0 43.7 44.7 49.0 44.6 41.1 47.4 34.7 39.0 40.7
32.3
46.7 46.3 50.3 49.9 46.8 46.1 51.8 49.9 51.2 51.7 46.3 50.3 51.9 55.5 55.8 54.1 54.5 54.4 54.2 55.3 57.2 63.0 63.4 65.1 63.7 64.9 62.8 51.9 55.5 55.8 59.9 57.5 55.8 55.5 55.8 51.9 55.5 55.8 59.9 57.5 55.8 63.7 64.9 62.8 53.3 53.4 54.4
47.8
131
47.6
129
50.9
131
52.0
130
54.4
133
54.4
129
55.5
130
63.8
131
63.8
130
54.4
133
54.46
133
51.3
136
54.4
134
56.0
134
63.8
132
52.3
138
34.4
37.8
33.7
35.8
43.5
44.4
50.5
50.5
44.4
35.8
34.3 46.4
45.5
44.4
41.0
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compressive strength in MPa
compressive Strength in MPa
60 50 40 30
7 days
20
28 days
10 0 1
2
3
4
age of curing
60 50 40 30
7 days
20
28 days
10 0 1
Fig. 1. Mixture of 1-1 to 1-4 (7 days and 28 days).
2
3
4
Compresive strength in Mpa
age of curing 60
Fig. 4. Mixture of 4-1 to 4-4 (7 days and 28 days).
50 40
Table 3 Details of tested cylindrical stubs.
30
7 days
20
28 days
10 0 1
2
3
Number of specimens
Number of WWM layers
WWM volume fraction (%)
2 2 2
0 2 4
0.0 1.1 2.2
4
age of curing 3.2. Preparation of plain concrete cylindrical stubs
compressive strength in MPa
Fig. 2. Mixture of 2-1 to 2-4 (7 days and 28 days).
70 60 50 40 30
7 days
20
28 days
10 0 1
2
3
age of curing
4
The undeniable concrete cylindrical stubs had been prepared the use of a normal concrete mix with a 28-day compressive rich of 25 MPa and stoop of 70–100 mm. The substances utilized in getting ready the concrete blend consist of regular Portland cement (ASTM Type I), crushed limestone coarse aggregate with a most length of 10 mm, an absorption potential of one. Fifty five, an oven dry bulk unique gravity of 2.60, a aggregate of washed sand and natural silica sand with an absorption capacity of 1.5% and 0.1% respectively, and an oven dry bulk precise gravity of 2.56 and a pair of 3.52 respectively, and faucet water. The concrete mix used consists of 300 kg/m3 Portland cement, 700 kg/m3 beaten limestone, 600 kg/m3 washed sand, 450 kg/m3 silica sand, and 195 kg/m3 unfastened water. The concrete mix was organized the use of a tilting drum mixer of 0.05 m3 ability. After casting, the stubs has been covered with wet burlap and saved within the laboratory at 23 °C and 65% relative humidity after which demoded and placed beneath water. After 28 days of curing, all stubs as kept in a wet environment until the date of casting the ferrocement jackets.
Fig. 3. Mixture of 3-1 to 3-4 (7 days and 28 days).
The Figs. 1–4 are Compressive strength versus age of curing for mortar mixes of 1-1, 1-2, 1-3, 1-4, 2-1, 2-2, 2-3, 2-4, 3-1, 3-2, 3-3, 3-4 and 4-1, 4-2, 4-3, 4-4 for 7 days and 28 days respectively. 3.1. Strengthening plain concrete cylindrical stubs The 2nd section of the examine become to analyze the overall performance of the developed high rich mortar mixes while used in ferrocement jackets to restrict cylindrical simple concrete stubs of 150 mm diameter and 300 mm height, below axial stresses. Table 3 indicates the information of tested stubs. Mortar mix 4-3, turned into selected for the second one segment of this investigation, due to the enhanced performance of the mortar mixes containing silica fume and Metakaolin [5,8].
3.3. Ferro cement jacket preparations The stubs have been sand-blasted to roughen their surface for a higher bond between the concrete floor and the implemented mortar layer. The WWMs used have 12.6 mm rectangular spacing and 0. 94 mm diameters, with yield rich of 385 MPa. The procedure of wrapping the WWM around the stub includes attaching the threshold of the twine mesh to the surface of the stub the use of a high adhesive bonding paste referred to as Sikadur-31; wrapping the desired number of layers across the floor, and providing an overlap of 10 mm at last layer. The joints of the mesh had been secured at one of kind locations collectively the use of double skinny metal wires which can be usually utilized in tying reinforcing bars. The mortar blend used for making ready the ferrocement jackets in this research had a 28 days compressive rich of about
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Fig. 5. Preparation of ferrocement jackets for cylindrical stubs.
Fig. 6. Axial load displacement curves for tested stubs.
63 MPa, and a float of 132%. (Mix 4-3, Table 2). All stubs wrapped with WWM had been first positioned in specifically designed molds that offer a 20 mm thick area around the stubs. To ensure that the ferrocement jackets most effective offer lateral confinement to the cylindrical stubs and now not contributing in growing its axial capability, the jackets were ended earlier than the stubs’ ends by 10 mm to prevent any direct axial load at the external ferrocement jacket in the course of test. Secondly the molds together with the stubs had been positioned at the pinnacle of a vibrating table, observed by pouring the mortar matrix and vibrated at low velocity for a period of 15 s, to reap complete penetration and consequently make certain that the mortar matrix encapsulates the WWM completely. The stubs had been remolded after 2 days and has been protected with wet burlap for as a minimum 14 days till testing (Figs. 5–9). 3.4. Preparation for testing and instrumentation The stubs have been organized for trying out via capping their top floor with a skinny gypsum layer to insure parallel surface and to distribute the load uniformly so one can reduce any eccentricity. The finished view of the stub after making use of the ferro-
cement jacket is proven in Fig. 1b. Axial displacements had been measured by way of using vertical linear variable differential transducers (LVDTs) of one hundred mm variety, mounted at 180 apart across the stub surface, in addition to any other two vertical LVDTs set up at one hundred eighty attached to the top of the gadget and the weight cell to measure the overall displacement and axial strain of the stub. The lateral displacements of the stubs were measured by the usage of horizontal LVDTs of the equal range established at a hundred and eighty apart attached to the floor of the stub; similarly to two outside horizontal stress gages to measure the stress at the jacket surface. The wire for stress gauges, the weight mobile, and the LVDT’s had been attached to facts acquisition system and checked for readings. The take a look at became performed the use of a hydraulic testing gadget with capability of 2000 KN and equipped with a shifting piston that exerts a downward axial pressure to test the stubs beneath pure axial compression. 3.5. Discussion of test consequences The resulted load-axial displacement curves of all examined stubs. It can be observed that the conduct of cylindrical stubs with
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Fig. 7. Axial stress and strain displacement curves.
Fig. 8. Axial load lateral displacement curves for cylindrical specimen.
Fig. 9. Typical failure mode for a control and jacketed cylindrical stubs.
ferrocement jackets either with or four layers of WWM are higher than the ones of manage stubs. The jacketed stubs’ curves have better load capacity at better axial traces as compared to the control stubs. For 4-layer ferrocement jackets the axial pressure reached up to 0.0035. In addition, slightly higher axial stiffness may be located in case of stubs with 4-layers WWM, due to the fact
of the lateral confinement provided by using the ferrocement jackets. The lateral displacement of all tested stubs at its mid peak had been plotted against the axial load. It may be referred to that the lateral displacement at most load are higher for jacketed stubs compared to the manage ones. Such better lateral displacements in jacketed stubs are attributed to the propagation and widening
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K. Sankar, D. Shoba Rajkumar / Materials Today: Proceedings xxx (xxxx) xxx Table 4 Summary of test results of cylindrical stub.
Control specimens
Specimens with 2 layers of WWM
Percentage increase for 2 layers of WWM Specimens with 4 layers of WWM
Percentage increase for 4 layers of WWM
1 2 Average 1 2 Average 1 2 Average
Peak axial stress (MPa)
Maximum axial strain
Maximum lateral displacement (mm)
35.0 38.0 36.5 43.0 41.0 42.32 15.9% 46.0 42.0 45.93 28.6%
0.00208 0.00211 0.00209 0.00272 0.00261 0.00275 31.6% 0.0362 0.0302 0.00356 70.3%
0.090 0.101 0.1005 0.1307 0.1302 0.1305 30.0% 0.3145 0.2145 0.264 163.0%
of the vertical cracks which can be related by way of yielding of the WWM, while sustaining its most axial load. Results of all examined stubs with their averages are given in Table 4, in terms of the most axial stress, most axial pressure and lateral displacement at most load. Results indicate that about sixteen% growth in axial load capacity that is related with approximately 32% boom in axial strain and 30% growth in lateral displacement were recorded for stubs wrapped with 2 layers of WWM Ferrocement jackets. While such probabilities growth for the stubs with four layers WWM to be approximately 29% increase in axial stress, 70% growth in axial pressure and approximately 163% growth in lateral displacement. The growth in stub’s lateral displacement turned into mainly attributed to the widening of the vertical cracks as the WWM is laid low with yielding. It is really worth citing that the increase in axial stress and axial traces had been nearly most effective due to the confinement presented by way of the Ferrocement jacket, since the jackets were no longer attaining the ends of the stubs. The standard conduct during check and the failure approach certainly determines that the oblique wires were subjected to hoop anxiety and thereby, creating passive captivity stress. The results as shown in Table 4.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] [2] [3] [4]
[5] [6] [7] [8] [9] [10]
4. Conclusion Based at the take a look at consequences of this investigation the subsequent conclusions can be drawn: 1. Greatest power mortar matrices having various combos of silica fume and Metakaolin, and addition of right percent of superplasticizer, can provide an excessive stability between flowability and rich. The matrices advanced had a 28 days compressive power range from forty eight to 64 MPa with an agreeing flow range from 129% to 138%. Among the matrices developed the ones that contained 15% silica fume or a combination of 10% silica fume and 10% Metakaolin via weight of cement, and approximately 3% superplasticizer, performed the best overall performance and hence can be used for generating high strength ferrocement laminates appropriate for structural repair/retrofit of concrete elements. 2. Considering the kind of specimens and parameters investigated, test outcomes indicated that wrapping cylinders of 150 mm diameter and 300 mm height, with 2 layers of WWM ferrocement jackets confirmed about 16% growth in axial load potential that is associated with approximately 32% growth in axial pressure and 30% growth in lateral displacement. Whereas, such probabilities boom for the stubs wrapped with 4 layers of WWM that showed approximately 29% boom in axial stress, 70% boom in axial stress and approximately 163% boom in lateral displacement.
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Further reading [19] P. Rathish Kumar, T. Oshima, S. Mikami, T. Yamazaki, Seismic retrofit of rectangular reinforced concrete piers with the aid of ferrocement jacketing. Structure and Infrastructure Engineering-Preservation, Control, Lifestylescycle, Layout and Performance, vol. Four, Taylor and Francis Institution Ltd., 2005. pp. 253–562.
Please cite this article as: K. Sankar and D. Shoba Rajkumar, Experimental investigation on different high rich cement mortar for ferrocement application, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.033