LAUSR

Curing of concrete is important to ensure both strength and durability. Loss of water through evaporation reduces the hydration rate and eventually results in limited strength and higher permeability. Generally, curing is done by supplying additional water from external sources to prevent the water loss. Such curing requires skilled labor and proper knowledge. However, in a developing country like Bangladesh, it is considered as an additional step and often neglected. Under such scenario, Internal Curing (IC) could be adopted to improve the overall quality of general concreting work. Utilization of locally available burnt clay chip aggregate commonly known as Brick Chips (BC) to produce internally cured concrete can be considered as an effective solution. The pore spaces of these aggregates absorb water during saturation process and later desorb water under favorable conditions of higher temperature and low relative humidity. As a result, no external curing water is needed. This study shows the durability performance of concrete having BC as internal curing medium. Stone chips have been partially replaced by BC since concrete with BC alone produces weaker concrete. Three commonly practiced water cement ratios of 0.4, 0.45 and 0.5 and five curing conditions were selected to simulate inside and outside environmental conditions. Three different percent replacements (10%, 20% and 30%) of stone chips by BC were selected. Control samples with stone chips were also made for comparison. Water permeability test and Rapid Chloride Permeability Test (RCPT) were performed. It is found that durability of internally cured concrete with polythene sheet covering is comparable to the durability of normally cured control concrete. Moreover, under adverse curing conditions with no supply of external water, internally cured concrete performed significantly better than control samples. Therefore, BC can be used as a cost effective internal curing material in Bangladesh to produce durable concrete.