Assessment of the quality of test results from selected civil engineering material testing laboratories in Tanzania

Abstract

Civil and geotechnical engineering material testing laboratories are expected to produce accurate and reliable test results. However, the ability of laboratories to produce accurate and reliable test results depends on many factors, among others, the competence of laboratory technicians, adherence to test procedures, as well as the condition of equipment. This paper assesses the quality of test results obtained from five selected civil and geotechnical engineering material testing laboratories in Tanzania. Three soil samples commonly found on construction sites in Tanzania were sampled and submitted to the selected five laboratories that were requested to perform the foundation indicator tests (particle size distribution, liquid limit and plastic limit). The test results from each of the five selected laboratories were analysed and compared, and thus demonstrated both the extent to which test results from different laboratories can vary and the impact that such variance has on the design of infrastructure. The assessments also highlighted the importance of laboratory accreditation and proficiency testing. To improve the quality of the results, laboratory accreditation and the implementation of a compulsory proficiency testing scheme for civil and geotechnical engineering material testing laboratories in Tanzania are recommended.