Effect of mixing time on fly ash block property
Ayan Kumar Keora
Development Alternatives, B-32, TARA Crescent, Qutab Institutional Area, New Delhi – 110016, India Abstract: This paper presents the effects of mixing time on the compressive strength of fly ash brick. Before designing the mix, sieve analysis of sand and fly ash was carried out and their fineness moduli were determined. Also the specific gravity and calorific value and ash content of fly ash were determined. The CaO content of lime also was determined by lime testing kit. The material batching is based on the composition derived from TARA laboratory report. Composition Sand Flay ash Virgin lime Phosphogypsum
50 50 9% of the total weight of sand and fly ash 3% of the total weight of sand and fly ash
The mixing duration was varying 6 minutes to 30 minutes. The strengths were measured at the curing ages of 28 days using compressive strength machine. The results revealed that the compressive strengths of fly ash bricks appreciably increased with increase in mixing duration from 6 minutes to 15 minutes but remained almost constant beyond 12 minutes for 28 days ages tested. For example, at 6, 8, 10, and 12 minutes mixing; the compressive strengths at 28 days 2 were 147.15, 149.59, 158.54, and 197.72 kg/cm respectively while at 14, 15, 20, 25 and 30 minutes mixing ; the compressive strengths at 28 days were 212.83, 2 216.54, 216.59, 221.34 and 227.12 kg/cm .
Keywords: Compressive strength, curing, machine mixing, mixing duration
Introduction Modern Construction prefers use of fly ash bricks. This one of the global go-green initiatives, and we are an active member of the same. This noble cause is supported by manufacturing and supplying bricks made from re-usable fly ash. Fly-Ash Bricks are an environment friendly cost saving building product. These bricks are 3 times stronger than conventional bricks with consistent strength. These bricks are ideally suited for internal, external, load bearing and non-load bearing walls. These Bricks with higher strength/weight ratio (about 3 to 4 times that of burnt clay bricks) aid in designing stronger, yet more economic structures. Fly Ash Bricks are durable, have Low water absorption, less consumption of mortar, Economical & ecofriendly, Low energy consumption and No emission of green house gases. These bricks are not affected environmental conditions and remain static longer building. wastages during thus life ensuring of the the ash and by
Also, in fly
savings with regard to bricks are considerable unloading construction due to true
shape and size, consistency in quality, and the workability of the fly ash bricks unlike traditional clay bricks. These bricks are very economical / cost effective, nil wastage while transporting and handling. Thus in recent times the use and production of fly ash bricks has demanded increasing significance. There are numerous machines and processes of fly ash brick production. Objectives This brief describes the optimum mixing time for improving the quality of existing fly ash brick properties without compromising on the technical qualities. Experimental Raw materials Fly ash: Fly ash was obtained from Dadri Thermal Power Plant, Delhi from ESP in the dry form. The fly ash conform IS 3812: 1981. Sand: The sand collected from the Sindh river in Datia district, Madhya Pradseh, India and used as fine aggregate was clean, sharp, free from clay and organic matter and well graded in accordance with IS Lime: Lime was sourced from local Datia market, Madhya Pradesh, India. Gypsum: Gypsum was bought from a reputed supplier at Datia market, Madhya Pradesh, India and it conformed to IS Water: Tap water was used for mixing and it was properly examined to ensure that it was clean, free from contaminants either dissolved or in suspension and good for drinking as specified in BS 3148 Table 1: Particle size analysis of various raw materials Grain Size 6mm – 2mm 2mm – 0.5mm 0.5mm...
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