Investigating strength and durability properties of Pozzomix-opc stabilised earth blocks

Abstract

This research investigates the effect of replacing earth with 5% (P5/0), 9% (P9/0) and 12% (P12/0) Pozzomix cement and 3% pozzomix + 2% OPC (P3/2), 6% pozzomix + 3% OPC (P6/3), 8% pozzomix + 4% OPC (P8/4) on the compressive strength, water absorption and abrasion resistance of earth blocks and to deduce the variable that contributes most to these parameters. The engineering characteristics of the soil from Bernatech campus, Navrongo carried out in accordance with BS1377:1990 reveals that soil fines and coarse fractions constitute about 46.8% and 53.2% therefore suitable for brick production. The total number of bricks selected for the tests were one hundred and forty five (145) and they were 230mm x110mm x 90mm in size. Also the strength and durability criteria of hand-made bricks were investigated after 28 days curing. Results indicate that all the specimens obtained recommended density values with the batch P3/2 recording the lowest (1764kg/m3) and P12/0 the highest (1997kg/m3) density. The analysis showed that pozzomix contributed the most (71%) to the density of earth bricks. Again all the stabilized earth bricks saw a steady increase in dry compressive strength of 2.06N/mm2, 2.28N/mm2, 2.41N/mm2, 2.47N/mm2, 3.15N/mm2 and 4.73N/mm2 for specimens P5/0, P9/0, P12/0, P3/2, P6/3 and P8/4 respectively. The control and the 5% Pozzomix specimens did not perform well in wet compressive strength. The entire specimens responded negatively to water intake with the specimens P8/4 recording an impressive 0.096g/cm2/min reduction. The abrasion test values were within acceptable range with batch P8/4 again resisting abrasion the most with a record of 11cm2/g. Generally the brick specimens saw an improvement when the percentages of the stabilizers increased. It is appropriate to conclude that the use of Pozzomix with OPC will improve significantly the strength and durability properties of compressed earth bricks. The use of Pozzomix cement alone should be used sparingly especially lower percentage and in poor soils