SELF-HEALING PROPERTIES OF CONCRETE CONTAINING SYNTHETIC SUPER ABSORBENT POLYMERS AND POLYVINYL ALCOHOL FIBERS

Abstract

Self-healing concrete research has increased greatly in the last decade, as researchers and the industry recognise the need to look into methods that reduce maintenance costs due to ageing infrastructures. Various research have studied the self-healing ability of concrete with different additives in terms of crack sealing, mechanical strength and water transportation properties. Additives such as fibers, bacteria spores and superabsorbent polymers have been used. The focus of this study is largely on the recovery ability of concrete – in terms of mechanical strength, water permeability and absorption due to addition of superabsorbent polymers, polyvinyl alcohol fibers, bacteria spores immobilised in biochar and/or directly added in the concrete matrix. Furthermore, baseline performance for each type of mix will be measured to observe differences to plain concrete. The results showed that overall, directly added bacteria spore with superabsorbent polymer and fiber as well as superabsorbent polymer and fiber only combinations performed the best and were comparable for the recovery properties measured, with either combination performing slightly better on some properties while worse for others. This is followed by biochar immobilised bacteria spore, superabsorbent polymer and fiber, and lastly plain concrete. The addition of bacteria spores had decreased baseline performance of the concrete drastically. The recovery performance for biochar immobilised bacteria spore samples has the best recovery performance for mechanical strength, but consistently poorest for both water penetration and absorption. There were anomalies observed for this combination for water absorption, and further testing is required. The limited sample size of taken for this study should be noted and further testing is needed to provide consistency of results.