An investigation of concrete curing practice in the Cape Town area

Includes bibliographical references.[Watermark not visible] This project describes the results from the use of durability index tests as a tool for the investigation of the concrete curing practice in the Cape Town area. The object of the tests was to determine the effect environmental conditions have on the physical properties of the outer skin of concrete. The laboratory work involved the exposure of three concrete strengths to various relative humidities. The site work involved testing the cured outer surface of concrete at 28 days on six construction sites. The oxygen permeability and water sorptivity tests were used to investigate the outer surface of concrete. The laboratory work showed that curing at a relative humidity of 90 had a beneficial effect on the durability index values, while curing at 60 relative humidity was less effective. The permeability and sorptivity of the site results remained constant as the actual strength increased. Furthermore, permeability and sorptivity increased as the average evaporation rate increased