26-08-2016, 02:17 PM
To Study the Partial Replacement of Cement by GGBS & RHA and Natural Sand by Quarry Sand In Concrete
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Abstract: Concrete is the most widely used construction material in civil engineering industry because of its high structural strength and stability. The concrete industry is constantly looking for supplementary cementitious material with the objective of reducing the solid waste disposal problem. Ground granulated blast furnace slag (GGBS) Rice husk ash (RHA) and Quarry sand (QS) are among the solid wastes generated by industry. To overcome from this crisis, partial replacement of natural sand (NS) with Quarry sand and partial replacement of cement with GGBS and RHA can be an economic alternative. This research is carried out in three phase, in first phase mix of M40 grade concrete with replacement of 0%,15%,30%,45%,60%,75%,90% and 100% of quarry sand with natural sand is carried out to determine the optimum percentage of replacement at which maximum compressive strength is achieved. It is observed that when natural sand is partially replaced with 60% quarry sand maximum strength is achieved. In second phase, cement is partially replaced with GGBS by 10%, 20% and 30%. In phase three, combination of GGBS and RHA is partially replaced with cement. The composition of 22.5% GGBS + 7.5% RHA with 60% of quarry sand gives good strength results.
Keywords: Admixture, Cement, Ground granulated blast furnace slag (GGBS), Quarry sand (QS), Rice husk ash (RHA).
I. Introduction
Concrete is a heterogeneous mix of cement, aggregates and water. The global consumption of natural sand is too high due to its extensive use in concrete. The demand for natural sand is quite high in developing countries owing to rapid infrastructural growth which results supply scarcity. To overcome from this crisis, partial replacement of natural sand with quarry sand is economic alternative. The concrete industry is constantly looking for supplementary cementitious material with the objective of reducing the solid waste disposal problem. Ground granulated blast furnace slag (GGBS), Rice husk ash (RHA) and Quarry sand (QS) are among the solid wastes generated by industry. Substantial energy and cost savings can result when industrial by-products are used as partial replacements for the energy- intensive Portland cement. This investigation attempts to study the feasibility of using locally available GGBS, RHA and QS as partial replacements for cement and sand in concrete. In this research we prepared specimen of cubes for compressive strength test, cylinder for split tensile strength test, beams for flexure strength test and permeable voids test. Three samples for each set of percentage have been taken for conducting test and average of results are taken. The samples were tested at the age of 7 days, 28 days and 56 days. The test on hardened concrete are destructive test while the destructive test includes compressive strength test as per IS: 516-1959, split tensile strength test as per IS: 5816-1999, flexure strength test as per IS: 516-1959, permeable voids test as per ASTM C642-97.
The objectives and scope of present study are –
1. To find the optimum percentage of replacement of natural sand with quarry sand at which maximum strength is obtained.
2. To use pozzolanic material such as GGBS and RHA in concrete by partial replacement of cement.
3. To conduct compressive strength test, split tensile strength test, flexural test.
4. To study and find permeable voids of the concrete mix and its relation with compressive strength of concrete.
5. To provide economical construction material.
6. Provide safeguard to the environment by utilizing waste properly.
7. To conduct acid resistant test.
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“To Study The Partial Replacement Of Cement By GGBS & RHA And Natural Sand By Quarry Sand In Concrete”
II. Materials Used
The materials used in experimental investigation include:
2.1. Cement
Ordinary Portland cement of 43-grade was used in this study conforming to IS:8112-1989 which has
Specific gravity 3.15, Normal consistency 32%.
Chemical Properties:
Table No.1: following are the chemical properties of Cement (OPC 43 Grade), RHA and GGBS
Material SiO2 Al2O3 Fe2O3 CaO MgO SO3 K2O Na2O LOI
3.73 62.91
Cement 19.71 5.20 2.54 2.72 0.90 0.25 0.96
RHA 83.87 (SiO2+ Al2O3+ 0.20 0.52 0.11 0.13 0.16 0.44
Fe2O3) = 86.19
GGBS 33.46 (SiO2+ Al2O3+ 25.02 7.97 0.85 1.28 1.32 13.61
Fe2O3) = 48.63
2.2. Ground Granulated Blast Furnace Slag (GGBS)
The GGBS used in research is obtained from Bhilai Steel Plant (Bhilai, Chattisgarh). Ground granulated blast-furnace slag is the granular material formed when molten iron blast furnace slag is rapidly chilled by immersion in water. It is a granular product with very limited crystal formation, is highly cementitious in nature and, ground to cement fineness, and hydrates like port land cement. The specific gravity of GGBS is 2.85.
2.3. Rice Husk Ash (RHA)
Rice husk ash used was obtained from Ellora Paper Plant located in Tumsar, Bhandara . RHA, produced after burning of Rice husk (RH) has high reactivity and pozzolanic property. The Specific gravity of rice husk ash is 2.12 and fineness of 71.80.
2.4. Aggregate
Good quality river sand was used as a fine aggregate conforming to Zone- II of IS: 383- 1970 have fineness modulus of 2.735, specific gravity of 2.5 and water absorption 0.98%. Quarry sand from sidheshwar quarry plant Pachgaon, Nagpur, conforming to Zone- II of IS: 383- 1970 have fineness modulus of 2.85 , specific gravity of 3 and water absorption 1%. The coarse aggregate passing through 20 mm and retained on 10 mm sieve was used in research. Its specific gravity is 2.85 and water absorption 0.8%.
2.5. Water
In this research potable water free from organic substance was used for mixing as well as curing of concrete.
2.6. Superplasticizer
AC-PLAST-BV M4 PLASTICIZER as a high range water reducing admixture for obtaining a workable mix was used in research, Strength increased 0.20 and Specific gravity 1.14.
III. Experimental Programme
3.1. Mixture Proportioning
The M40 mix proportioning is designed as per guidelines, according to the Indian Standard Recommended Method IS 10262- 2009. The total binder content was 400 kg/m³, fine aggregate is taken 668.9529 kg/m³ , coarse aggregate is taken 1301.122 kg/m³. The super plasticizer content was varied to maintain a slump of 60 mm for all mixtures. This research is carried out in three phase, in first phase mix of M40 grade concrete with replacement of 0%,15%,30%,45%,60%,75%,90% and 100% of quarry sand with natural sand is carried out to determine the optimum percentage of replacement at which maximum compressive strength is achieved. In second phase, cement is partially replaced with GGBS by 10%, 20% and 30%. And in third phase combination of GGBS and RHA is partially replaced with cement. Cubes, beams and cylinder moulds were used for casting. The total mixing time was 5 minutes; Compaction of concrete in three layers with 25 strokes of 16mm rod was carried out for each layer is done. The concrete was left in the mould and allowed to set for 24 hrs before the cubes were demoulded and placed in curing tank until the day of testing.The three specimens of each set was prepared and left for curing in the curing tank for 7,28 and 56