GENERAL
Fly ash is a waste product from thermal power plants where pulverized coal is used for the as per the literature review GouravHYPERLINK "http://biblioteca.universia.net/autor/Gourav,%20K.html", Studies, 2007. Fly ash is being utilized in the blended cements, additive for concrete and manufacturing of concrete blocks and bricks. Fly ash-lime-gypsum bricks are being manufactured and marketed throughout the country. The literature review on fly ash-lime-gypsum (FALG) mixtures as intended to manufacture bricks or blocks for masonry applications indicates several gaps in understanding the various aspects of the technology.
The present thesis is an attempt to understand the behavior of compacted stabilized fly ash mixtures for the manufacture of fly ash bricks and characteristics of masonry using such bricks. A brief introduction to the technology of compacted stabilized fly ash bricks for structural masonry is provided. The main focus of the investigations is on arriving at the optimum stabilizer-fly ash mixtures considering density, stabilizer-fly ash ratio, curing conditions, etc. as the variables. Therefore the parameters/variables considered in the investigation include: (a) density of the compacted fly ash mixture, (b) stabilizer-fly ash ratio, (c) curing duration (normal curing and steam curing) and (d) dosage of additives like gypsum.
The investigations clearly show the possibility of producing bricks of good quality using compacted fly ash-lime gypsum mixtures. Wet compressive strengths of 8- 10 MPa was obtained for compacted fly ash-lime-gypsum bricks at the age of 28 days. Wet strength to dry strength ratio for these bricks is in the range of 0.55 – 0.67. Initial tangent modulus for the fly ash-lime-gypsum bricks in saturated condition is in the range of 8000 – 12000 MPa. There is a large scope for selecting optimum mix ratios of Fly ash, sand, lime and other