Assessment of Compressive Strength Variations of Concrete Poured in-Site of Residential Buildings in Isoko District, Delta State, Nigeria

Concrete with appreciable compressive strength is required for building constructions, to minimize the occurrence of building failures. Determination of the compressive strength of in-situ concrete produced in Isoko region of Nigeria was carried in this study. Concrete used for the construction of foundation wall footings for twenty residential buildings were sampled in the study. The compressive strength of the in-situ concrete was determined in accordance with ASTM standards. Field survey depicted that most (60%) of the concrete quality production process fell below the approved standard of 17 MPa, for residential buildings. The findings of the study revealed that the compressive strength of the in-situ concrete varied between 8.1 MPa and 19.8 MPa. Furthermore, the result of the compressive strength test showed that most (70%) of the in-situ concrete failed to meet the NIS recommended standard. Also, it was observed from the findings that proportionally, the concrete produced by conventional building/construction engineers was of a higher compressive strength, when compared to the concrete produced solely by masons. Based on observations obtained result obtained from this study, it is recommended that the Government should constantly educate building sites managers, on the need to adhere strictly to standard recommendations, in order to improve the quality of in-situ concretes produced.