ABSTRACT

The spate of building collapse in Nigeria has put in the front burner the need to investigate the quality of sandcrete blocks used in building construction. Collapse and heavy cracks are the frequent features of many building in Uyo capital city of Akwa Ibom State, Nigeria. There are many causes for collapse of building; one of which is weak and poor quality walling units, for example hollow sandcrete blocks. Therefore, this research work assessed the compressive strength and water absorption qualities of hollow sandcrete blocks produced in Uyo capital city of Akwa Ibom State, Nigeria. Three types of investigation, namely; literature review, field survey and laboratory experimentation procedures were used for the method. A total number of one hundred and eight (108) hollow sandcrete blocks were randomly collected. Twelve (12) blocks sampled from each of the nine (9) local government area of Uyo Capital City.  Blocks sampled collected were tested at the age of 28days for their compressive strength and water absorption being two major characteristic requirement specified by Nigerian industrial standard for sandcrete blocks for testing and verifying the quality of sandcrete blocks, apart from the appearance and dimension. Structure interview was conducted at each factory with some of the factory staff to elicit further information on their production. All the tests were carried out in the soil laboratory, department of civil engineering, ministry of works Uyo, Akwa Ibom State, Nigeria. Test results shows that, there was no appreciable difference in water absorption values of the produced at the nine industrial sites. However, the water absorption values obtained are not higher than 12% specification. The average means of compressive strength of nine inches blocks (machine production) is 2.01N/mm² and the manual production is 1.78N/mm². However, for six inches blocks, the average means of compressive strength are 1.80N/mm² and 1.69N/mm² for the machine and manual productions respectively. This is far below the 2.5 N/mm² recommended by Nigerian Industrial Standard (NIS) for non-load bearing walls and 3.45n/mm² for load bearing walls. The result shows that, the blocks produced in Uyo, both machine and manual productions do not meet the minimum requirements by NIS, therefore it cannot be used for the construction of building. The study revealed that, poor quality control, poor selection of constituent materials, poor control of mix ratio and inadequate curing period by the producers contributed to the negative results obtained. It is recommended that workshop should be organized periodically to enlighten the block producers in the locality.