Characterization of the Compressive Strength of Sandcrete Blocks in Ondo State, Nigeria

Abstract

Research activities in different countries have shown that the compressive strengths of sandcrete blocks are always far below the recommended values in the codes. This work reports the compressive strengths and the statistical characteristics of sandcrete blocks collected from twenty five (25) different block industries in Ondo State, Nigeria. A total of seventy five (75) of 450 mm x 225 mm x 225 mm and seventy five (75) of 450 mm x 150 mm x 225 mm blocks were collected and tested. The results showed that the 450 mm x 150 mm x 225 mm sandcrete blocks in circulation as at May 23, 2005 had an average strength of 0.55 N/mm2 while those of 450 mm x 225 mm x 225 mm had an average compressive strength of 0.45 N/mm2 as at November 13, 2005. These values are very much lower than those stipulated by the relevant Codes and Standards. Although statistical analysis showed that the compressive strength of these blocks followed a normal distribution, the overall coefficient of variation stood at 0.54 for the 450 mm x 150 mm x 225 mm blocks and 0.71 for the 450 mm x 225 mm x 225 mm blocks. These values are high and they indicate very poor quality control in the production processes. On the basis of the noted poor quality control, recommendations appropriate for improving the strength and effectiveness of sandcrete blocks production in Nigeria are made.

Keywords: Sandcrete Blocks, Compressive Strength, Mix Ratio

Journal of Civil Engineering Research and Practice Vol. 5 (1) 2008: pp. 15-28