Evaluating the Suitability and Mechanical Properties of Sandcrete Blocks Produced from Borrow Pits Sands in some Communities in Isoko, Delta State, Nigeria

Abstract

This research was conducted to establish the suitability of dredged (borrow) pits “white sand” in sandcrete block production. White sand was collected from six major sand dredging sites in the Isoko district of Nigeria. Some geotechnical properties (porosity and particle size grading) were done on the sand following American Society for Testing and Materials (ASTM) approved methods. Also, the sand particle size compressive strength was determined through sandcrete blocks produced according to ASTM standards. Two sets of sandcrete blocks were produced with different cement–sand mix ratios; which were mix ratio 1 (mix ratio of 1:8) and mix ratio 2 (mix ratio of 1: 10). Results from the geotechnical test revealed that the majority (66.7%) of the sand were poorly graded sand, while their porosity varied from 34.9% to 41.1%. Additionally, blocks produced through mix ratio 1 had compressive strength that varied from 1.34 MPa - 2.21MPa; while the mix ratio 2 blocks compressive strength ranged between 1.12 MPa and 1.85 MPa. Remarkably, none of the sandcrete blocks regardless of the cement-sand mix ratio met the approved Nigeria Industrial Standard (NIS) recommended compressive strength for sandcrete blocks - load-bearing walls of 3.45MPa and non-load-bearing walls of 2.5 MPa. Hence, the low compressive strength of the sandcrete blocks produced from the studied region white sand should be of major concern to stakeholders, to prevent the occurrence of building collapses in the region