STRUCTURAL CHARACTERIZATION OF SANCRETE HOLLOW BLOCKS, PRODUCED BY SELECTED CEMENT BRANDS IN NIGERIA (BUA, DANGOTE, MANGAL O P C)

ABSTRACT The current wave of collapse of building structures all over the world including Nigeria necessitates the need to carry out research on the properties of the construction materials. Concrete and sandcrete hollow blocks are major construction materials used in the building industry. The objective of this study is to determine the properties of sandcrete hollow blocks (SHB) produced by three (3) selected brands of ordinary Portland cement (BUA, DANGOTE, and MANGAL). The cement brands were purchased from local markets in Nigeria. The water, sand, gravel and the cement brands were characterized and results compared with the British standards (BS EN 1008:2002 for water, BS EN 12620 for sand and gravel, and BS EN 197-1: 2011for cement) in order to determine their suitability for production of sandcrete hollow blocks. A total of 84 SHB produced from the above materials were investigated. Tests were conducted on the SHB to determine: the optimum water to cement ratio, dry and wet strengths, density development and water absorption. Results were compared with British Standard. SHB cured and soaked in water for 14 days (wet state), Results were compared with British standard. This was observed for SHB produced from the three cement brands mentioned above, and mix ratio range of 1:6. The characteristic strengths of the concretes produced from cement brands were 31.81, 31.80, and 27.90 N/mm2 respectively. The local cement brand B (BUA) did not meet the standard specifications. The compressive strengths of the SHB produced from cement brands A (DONGOTE) to C (Mangal) were higher than the minimum standard strength of 2.9N/mm2 (BS EN 771:2006). It was inferred from the study that wall constructed of SHB experiences a sharp drop in strength after one day saturation by flood. Concretes produced from the local cement brands B (BUA) has strength lower than the minimum standard strength of 30N/mm2 (BS EN 206: 2000) due to non-compliance with the cements silicate compounds to the standard. Concretes produced from imported cement brands B (BUA) and C (Mangal) met the standard. It was suggested that SHB should be subjected to additional standard test after one day immersion in water based on the above established phenomena.