Effect of Wood Ash and Sawdust Ash Admixtures on the Engineering Properties of Burnt Laterite-Clay Brick from Igboora

Abstract

Abstract: An attempt to reduce the amount of environmental wastes and the high cost of conventional stabilizers has led to continuous studies on the economic utilization of ash from agro-wastes for improving the engineering properties of burnt brick. This paper reviewed the effect of addition of sawdust ash and wood ash admixtures to a 70:30 parts by weight laterite-clay mix. The admixtures were added in various combinations of proportions by weight (from 0 to 10%). The natural laterite-clay used was classified according AASHTO and USCS as A-7-5 and MH-OH respectively, and the there was general increase in compressive strength of the brick with increase in admixture and sample D (SDA:7.5% and WA:2.5%) has highest value of 11.45 MN m-2. The sample D with samples B and E were categorized as first class bricks with compressive strength higher than 10.3 MN/m2, therefore, adequate for structural building bricks in Grade NW condition. While samples A and C are also categorized as second class brick with compressive strength higher than 7.0 MN/m2., therefore adequate for general construction bricks work in Grade NW condition. The control sample X is categorized as third class brick with compressive strength between 3.5-7.0 MN/m2 (ASTM C62 99, 2000). The 24 hour water absorption capacity generally increased from 15.65% for control sample x to highest value 24.35% for sample D, this was due to change in internal structure during firing.Key words: Burnt brick, engineering properties, laterite-clay