Journal of Pure and Applied Ultrasonics

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Impact Of Substitution Of Silica Nanoparticles On Compressive Strength Of Concrete


Affiliations
1 Dept. of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal-576104, Karnataka, India
2 2Nanoscience Centre, Department of Physics, VKS University Ara-802301, Bihar, India

In present work, we studied the effect of substitution of silica nanoparticles (SNPs), by replacement of cement on ultrasound pulse velocity and compressive strength of concrete specimens. We also obtained correlation between ultrasound pulse velocity (UPV) and the compressive strength. The mean particle size of silica nanoparticle (in this study) was 20 nm. The quality of concrete specimens was assessed by measuring ultrasound pulse velocity (UPV) in m/s and compressive strength (N/mm2). The average value of UPV on 7th day of curing turned out to become 3200±36, 3215±42, 3290±41, 3349±24, 3450±17 and 3456±12 for 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% content of SNPs in the specimens respectively. Similarly, the average value of UPV on 28th day was 3540±36, 3580±38, 3696±42, 3820±39, 4160±40, 4163±41, for same amount of substitution of SNPs respectively. On comparison of the results of UPV on 7th and 28th days, the overall quality of concrete was found very good on the basis of UPV assessment. The UPV was consistently higher on 28th day in comparison with 7th day data, obviously, because the samples were getting stronger with time. Further, the UPV was higher in the specimens containing silica nanoparticles, the silica nano-particles were replaced by weight of cement and it had been observed that the concrete specimens had achieved maximum strength at nearly 2% (that is in between 2.0-2.5%) content of SNPs. The average compressive strength on 7th day turned out to become, 25, 25, 27.6, 30, 32.4 and 32 N/mm2 for 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% content of silica nanoparticles in the specimens respectively. But, on 28th day the average compressive strength it was 38, 38.5, 40, 42, 48.5 and 48.8 N/mm2 for 0%, 1.0%, 1.5%, 2.0%, 2.5%. As UPV increased so did the compressive strength. We observed strong correlation (correlation coefficient 0.997) between USV and compressive strength and variance (R2=0.87), which meant 87% of variation of compressive strength could be explained by variation of USV for the specimens (which acquired its compressive strength) on 28th day. Compressive strength and USV increased due to hydration reaction leading to C-S-H (Calcium-Silicatehydrate) gel formation which filled the pores in the concrete matrix, making it stronger and the pores filling nature of inactive silica-particles made the specimen compact and strong. The compressive strength of concrete significantly increased with content of silica nano-particles within the selected range of content (1.5-2.5%), but there is limitation due to agglomeration of nanoparticles, in fact, agglomeration destroys the salient features nano-particles.
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  • Impact Of Substitution Of Silica Nanoparticles On Compressive Strength Of Concrete

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Authors

Chaitanya Chauhan
Dept. of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal-576104, Karnataka, India
Raviraja Adhikari
Dept. of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal-576104, Karnataka, India
Anil Kumar Singh
2Nanoscience Centre, Department of Physics, VKS University Ara-802301, Bihar, India

Abstract


In present work, we studied the effect of substitution of silica nanoparticles (SNPs), by replacement of cement on ultrasound pulse velocity and compressive strength of concrete specimens. We also obtained correlation between ultrasound pulse velocity (UPV) and the compressive strength. The mean particle size of silica nanoparticle (in this study) was 20 nm. The quality of concrete specimens was assessed by measuring ultrasound pulse velocity (UPV) in m/s and compressive strength (N/mm2). The average value of UPV on 7th day of curing turned out to become 3200±36, 3215±42, 3290±41, 3349±24, 3450±17 and 3456±12 for 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% content of SNPs in the specimens respectively. Similarly, the average value of UPV on 28th day was 3540±36, 3580±38, 3696±42, 3820±39, 4160±40, 4163±41, for same amount of substitution of SNPs respectively. On comparison of the results of UPV on 7th and 28th days, the overall quality of concrete was found very good on the basis of UPV assessment. The UPV was consistently higher on 28th day in comparison with 7th day data, obviously, because the samples were getting stronger with time. Further, the UPV was higher in the specimens containing silica nanoparticles, the silica nano-particles were replaced by weight of cement and it had been observed that the concrete specimens had achieved maximum strength at nearly 2% (that is in between 2.0-2.5%) content of SNPs. The average compressive strength on 7th day turned out to become, 25, 25, 27.6, 30, 32.4 and 32 N/mm2 for 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% content of silica nanoparticles in the specimens respectively. But, on 28th day the average compressive strength it was 38, 38.5, 40, 42, 48.5 and 48.8 N/mm2 for 0%, 1.0%, 1.5%, 2.0%, 2.5%. As UPV increased so did the compressive strength. We observed strong correlation (correlation coefficient 0.997) between USV and compressive strength and variance (R2=0.87), which meant 87% of variation of compressive strength could be explained by variation of USV for the specimens (which acquired its compressive strength) on 28th day. Compressive strength and USV increased due to hydration reaction leading to C-S-H (Calcium-Silicatehydrate) gel formation which filled the pores in the concrete matrix, making it stronger and the pores filling nature of inactive silica-particles made the specimen compact and strong. The compressive strength of concrete significantly increased with content of silica nano-particles within the selected range of content (1.5-2.5%), but there is limitation due to agglomeration of nanoparticles, in fact, agglomeration destroys the salient features nano-particles.