A Study on Suitability of Foamed Sandcrete Solid Block with Fly-Ash as Partial Replacement of Sand

Abstract

In this study, the properties of foamed sandcrete solid block (FSSB) with varying percentage of sand replacement with fly-ash were investigated. These properties include workability, wet and dry density, stability, water absorption capacity and compressive strength. 150mm cube specimens were used for the determination of both the compressive strength and the dry density of the FSSB. The plastic density was investigated using a container of known volume, and its workability determined using the slump test. The fly-ash content was varied from 0 to 50% at interval of 10%. The specimens without the fly-ash served as the control. At the designed density of 1500kg/m3, the results for the control specimens at 28 day curing age was 3.74N/mm2. As for 50% sand replacement with fly-ash, the compressive strength were 2.37 N/mm, and 3.31 N/mm2 at 7-days 28-days curing age respectively, both satisfied the minimum compressive strength of 1.8N/mm2 and 2.5N/mm2 at the curing age of 7-days and 28-days respectively for conventional sandcrete block for building wall unit as allowed by Nigerian Industrial Standard (N.I.S). The result also shows an appreciable decrease in density of FSSB with 1411.8kg/m3, as compared to dense sandcrete solid block with average of 1950kg/m3, which will significantly reduce the overall dead load of the building structure. FSSB with 50% sand replacement with fly-ash also showed a much improved water absorption capacity of 9.81% as control specimen of 11.73%. Fly-ash can be used to reduce the quantity of sand used in FSSB production; thus ridding our environment of potentially harmful wastes, as well as reduce the consumption of non-renewable resources. Keywords— Foamed Sandcrete, Compressive Strength, fly-ash, dry density, stability, cement