Analysis of Chemical Admixture use on the Quality of Concrete in Nairobi County, Kenya

Abstract

Quality of concrete has been the focus of key stakeholders in the construction industry of Kenya for quite a while now. The main question has been, ‘what exactly leads to concrete failure’ and has inspired inquiry into the (i) quality of the materials used; (ii) design mix adopted; (iii) methods of batching the materials; (iv) methods of handling and placing concrete; and (v) use of additives to add value. This study set out to establish whether chemical admixtures are being used in the construction industry of Kenya and whether they actually enhance the quality of concrete in the industry. The study adopted a mixed research strategy - incorporating qualitative and quantitative research approaches – and used a cross-sectional research design. A sample of 62 contractors from Nairobi County - registered under Category 1 of the NCA (National Construction Authority of Kenya) - were used for data collection in this research, which was done using a questionnaire. Both qualitative and quantitative data were collected. Descriptive analysis of the data was done on the quantitative data - using the Statistical Package for Social Sciences (SPSS for Windows) - while thematic analysis done on the qualitative data. The study established the use of accelerating, retarding, viscosity improving, air entrainment and waterproofing admixtures in Nairobi County. The study came to the conclusions that chemical admixtures are currently used in the construction industry of Kenya to improve the quality of concrete, and that use of the admixtures enhances construction project management in the industry. The study recommends formulation of legislation to guide use of the admixtures. This legislation should address the current challenge of counterfeit chemical admixtures and improve training of contractors in the application of the admixtures.