scholarly journals EFFECT ON COMPRESSIVE STRENGTH OF CONCRETE BY USE OF NANO SILICA AS PARTIAL REPLACEMENT OF CEMENT

2017 ◽  
Vol 5 (1) ◽  
pp. 64-75
Author(s):  
Prakash Mallappa Munnoli ◽  
Tejashwini R. Pattar ◽  
Jyoti S. Garawad

Investigations were carried out on the changes in properties of concrete when steel slag is used in concrete in its normal form and after modifying its properties by infusing it with nano-silica. The sand is replaced by steel slag and modified steel slag by 10%, 20% and 30% in M30 grade concrete. Tests results on compressive strength and workability of concrete revealed that compressive strength of concrete cubes after 28 days increased by 25.4%, 26.4% and 45.2% for 10%, 20% and 30% respectively after replacing sand by steel slag. After modification of steel slag properties by infusing it with nano silica, the 28 days compressive strength was observed to be increased by 38.19%, 35.80% and 27.89% for 10%, 20% and 30% as compared to traditional concrete mix respectively after replacement. Infusing steel slag with nano silica increased the compressive strength of concrete mix by 20.17%, 25.74% and 49.64% for 10%, 20% and 30% respectively when compared to normal steel slag concrete mix. It was also observed that using steel slag in concrete mix also influences on water consumption in concrete mix. Workability tests conducted using 0.45 and 0.5 w/c ratio and the inference was that the workability increased with the increase in percentage of steel slag but workability decreases with the increase in percentage of modified steel slag.


2020 ◽  
Vol 2 (1) ◽  
pp. 31-57
Author(s):  
Ni Ketut Sri Astati Sukawati

Concrete with various variants is a basic requirement in building a building. The concrete mixture is diverse depending on the planning made beforehand. The cement mixture is usually in the form of a mixture of artificial stone, cement, water and fine aggregates and coarse aggregates. Aggregates (fine aggregates and coarse aggregates) function as fillers in concrete mixtures. (Subakti, A., 1994). However, in building construction, additives are often added, but there is still a sense of uncertainty at the time of dismantling the mold and the reference before the concrete reaches sufficient strength to carry its own weight and the carrying loads acting on it. To overcome the time of carrying out work related to concrete, it is necessary to find an alternative solution, for example by looking for alternative ingredients of concrete mixture on the basis of consideration without reducing the quality of the concrete. From the results of previous studies it was stated that due to the partial replacement of cement with Fly Ash, the strength of the pressure and tensile strength of the concrete had increased (Budhi Saputro, A., 2008). Based on the description above, the author seeks to examine how the compressive strength of concrete characteristics that occur by adding additives Addition H.E in the concrete mixture and is there any additive Additon H.E effect on the increase in the compressive strength characteristic of the concrete. From the results of the study, it was found that the compressive strength of the concrete with the addition of additives HE was that after the compressive strength test of the concrete cube was carried out and the analysis of concrete compressive strength of 10 specimens, in each experiment a cube specimen was made with the addition of additons. HE with a dose of 80 cc, 120 cc, and 200 cc can accelerate and increase the compressive strength of concrete characteristics.


This paper presents an experimental investigation on the properties of concrete in which like cement is partially replacing by used nano silica and is partially replacing by used waste foundry sand. Because now a day the world wide consumption of sand as cement and as fine aggregate in concrete production is very high. Nano silica and waste foundry sand are major by product of casting industry and create land pollution. The cement will be replaced with nano silica and the river sand will be replaced with waste foundry sand (0%, 5%, 10%, 15%, 20%). This experimental investigation was done and found out that with the increase in the nano silica and waste foundry sand ratio. Compression test has been done to find out the compressive strength of concrete at the age of 7, 14, 21, and 28. Test result indicates in increasing compressive strength of plain concrete by inclusion of nano silica as a partial replacement of cement and waste foundry sand as a partial replacement of fine aggregate.


2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.


2012 ◽  
Vol 204-208 ◽  
pp. 3970-3973
Author(s):  
Reagan J. Case ◽  
Kai Duan ◽  
Thuraichamy G. Suntharavadivel

As a part of a large research program aiming at the cementitious materials containing recycled materials at Central Queensland University – Australia, the current paper presents the preliminary results of a study on the effects of fly ash, which is used to replace cement in concrete, on the concrete compressive strength. For this purpose, systematic experiments have been carried out to investigate the influences of fly ash ratio and age. The compressive strength of concrete specimens with replacement ratios of 15%, 30% and 45%, and aged 7 and 28 days are measured and are compared with those of the concrete specimens without fly ash at the same ages. The results demonstrate that the strength of fly ash containing concrete improves more slowly but more strongly with aging, than their fly ash free counterparts, and an optimum fly ash replacement ratio exists where the maximum compressive strength of fly ash containing concrete can be achieved, and the maximum strength for the specimens aged 28 days and above is higher that of fly ash free concrete. Furthermore, the observation strength behaviours are analysed and discussed in terms of the influences of fly ash on interface reactions and interface bonding strength.


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