Quality assessment of sandcrete blocks produced in Adeta, Kwara State, Nigeria

Abstract

The durability of a building is determined to a great extent by the quality of materials used in its construction. Sandcrete block is a major building material in Nigeria. This research assessed the quality of blocks produced in Adeta, Ilorin West Local Government Area of Kwara State, Nigeria. Eight block factories were selected from the study area and the quality of their blocks were measured for their water absorption ratios and compressive strengths and compared with the Nigerian Industrial Standards (NIS) specifications. Six samples each of size 450mm x 225mm x 225mm per factory were tested. Experimental findings revealed that the absorption rate of the sandcrete blocks were higher than the 12% specification. The compressive strengths of the blocks which ranges from 0.19N/mm 2 to 0.40N/mm 2 fall below the minimum specification of 2.5N/mm 2 . Inadequate mix ratio is a factor that resulted in the poor quality sandcrete blocks produced in the area.

Quality assessment of commercially produced sandcrete blocks in part of Akwa Ibom State, Nigeria

“…These compressive strength values all fall far below the minimum specified compressive strength by NIS 87: 2007 for load bearing and non-load bearing walls being 3.45N/mm 2 and 2.5N/mm 2 respectively. However, these results are not quite different from those obtained by several other researchers in different cities [1,4,6,7,8] and it confirms that sandcrete blocks produced by block manufacturers into our building industry are of consistently poor standard.…”

“…From the report, mean compressive strength of blocks industries ranged from 0.75 to 2.19N/mm 2 while the mean water absorption ranged from 12.94 to 16.95%.In a study by Aiyewalehinmi and Tanimola [8] in Akure, the mean compressive strength was between 0.61 and 0.63N/mm 2 . Similar surveys have also been carried out in Calabar [6], Adeta, Kwara state [4], Ibadan [7] and Owerri [1] with similar or even worse results. All these show the non-compliance of sandcrete block industries to the NIS standard in most cities in Nigeria.…”

“…In Nigeria, blocks are usually produced in either solid or hollow rectangular forms. Solid blocks have no opening but hollow blocks are produced with two cavities from top to bottom on each block and these voids occupy about one-third of the total volume of each block [4], hereby reducing its unit weight. Typically, in the production of sandcrete blocks, the materials are thoroughly mixed until a homogenous mix with uniform colour is obtained.…”

“…Sometimes even when the building has not collapse, the aesthetics value is lost to cracks and other defects [4]. To solve this problem, Nigerian Industrial Standard (NIS 87:2007) which is a standard reference document for manufacturing of sandcrete blocks in Nigeria; specifies the minimum characteristics compressive strength of sandcrete blocks as 2.5N/mm 2 and 3.45N/mm 2 for non-load bearing and load bearing walls respectively [3,4,6,7]. The document also specifies maximum water absorption as 12% [4].…”

“…To solve this problem, Nigerian Industrial Standard (NIS 87:2007) which is a standard reference document for manufacturing of sandcrete blocks in Nigeria; specifies the minimum characteristics compressive strength of sandcrete blocks as 2.5N/mm 2 and 3.45N/mm 2 for non-load bearing and load bearing walls respectively [3,4,6,7]. The document also specifies maximum water absorption as 12% [4]. However, cases of building failures are still rampant because as revealed by several researches, compliance to the NIS standard by sandcrete block industries is very poor in most cities in the country.…”