IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Special Issue: 01 | NCRTCE-2014 | Feb-2015, Available @ http://www.ijret.org 47 IMPLICATION OF PARTIAL REPLACEMENT OF CEMENT WITH FA AND SAND BY GBS ON SETTING TIME AND WORKABILITY OF MORTAR Sunil N Manjunath 1 , P V Sivapullaiah 2 , M Prasanna Kumar 3 1 M.Tech Student, Department of Civil Engineering, Manipal Institute of Technology, Manipal, Karnataka, India – 576104, sunilnm09@gmail.com 2 Professor, Department of Civil Engineering, Indian Institute of Science, CV Raman Road, Yeshwanthpura, Bengaluru, Karnataka, India – 560012, siva@civil.iisc.ernet.in 3 Asst. Professor, Department of Civil Engineering, Manipal Institute of Technology, Manipal, Karnataka, India – 576104, prasannakumar18186@gmail.com Abstract Fly Ash (FA) and Ground Blast Furnace Slag (GBS) are by-products obtained from the burning of coal in the thermal power plants and blast-furnace used to produce iron respectively. With a view to preserve natural materials like river sand and high energy consuming cement efforts are made to explore the possibility of replacing them with alternate materials including the industrial solid waste materials in the production mortar and concrete. It is in this context the setting time of FA and the workability of mortar are examined with these replacements. In the present investigation, 25% and 50% of Cement (C) is replaced by FA; and 25%, 50%, 75% and 100% of Sand (S) by GBS. Normal consistency and setting time increased with increasing replacement of cement with fly ash. However, the addition of 2% Calcium Chloride reduced the setting time of all pastes. Also, the results indicated that cement with upto 50% of FA can be considered without seriously jeopardizing the setting time. The workability test on 1:3 mortar on all combinations were performed to get a flow value of 110 + 5 as per IS 2250 -1981. To enhance the workability and consequently increase their strength 2% of super plasticizer has been incorporated. The water cement ratio increased with increase in replacement of sand by GBS. The replacement by FA upto 50% did not reduce the water cement ratio of normal cement mortar. Also, workability tests on mortar samples have shown that, GBS can be used up to 50% of sand. Keywords: Cement, FA, GBS, mortar, natural sand, replacements. --------------------------------------------------------------------***------------------------------------------------------------------ 1. INTRODUCTION Cement manufacturing is highly energy and emissions intensive because of the extreme heat required to produce it. Producing a ton of cement requires 4.7 million BTU of energy, equivalent to about 400 pounds of coal, and generates nearly a ton of CO 2 . Given its high emissions and critical importance to society, cement is an obvious place to look to reduce greenhouse gas emissions. Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, depending on the local rock sources and conditions. The construction industry demands only specific type of sand, for making mortar and concrete. This has lead to a huge demand and degradation of natural sources. Therefore, finding of alternative ways to meet the growing demand is of high priority in modern times. In order to achieve reduced environmental pollution and impact use of by-products to replace cement by Fly Ash (FA) and sand by Granulated Blast furnace Slag (GBS) has been proposed in this research. Radwan et al (2012) in their research paper had worked on substitution of Portland cement(C) pastes by GGBS. Priyanka et al (2013) experimental program studied the effect of replacement of natural sand by manufactured sand on the properties of cement mortar. Swaroop et al (2013) studied on the durability properties of concrete with the replacement of cement by Fly Ash and GGBS. Essam et al (2013) carried out a research work on Effect of calcium chloride on the hydration characteristics of ground clay bricks cement pastes. Marthong et al. (2012) conducted a research on effect on use of fly ash as an additive on concrete properties. Isa et al. (2006) in their research paper had studied the effect of replacement of sand by GBS and coal bottom ash in concrete strength and durability. These earlier researches have shown that of GBS and FA, in mortar and concrete can be used as a substitute material for sand and cement respectively. Based on the review, research has been carried out on evaluating normal consistency, initial and final setting time, and with effect on flow characteristics on substituting FA and GBS in place of cement and natural sand respectively. 2. RESEARCH SIGNIFICANCE The objectives of the research are to study effect of FA on cement and GBS on sand. They are used in preparation of mortar with replacement materials. FA was substituted as 25% and 50% in place of cement with GBS substituted as