An investigation of the compatibility of different approaches to self-healing concrete: The superabsorbent polymers and microbially inducedcalcite precipitation

Abstract

The concept of the self-healing concrete, thus an improvement of the durability of concrete structures, has become a widely investigated topic in recent decades.The aim of this study is to examine apossible combination of two existing approaches to the spontaneous crack-sealing –the biologically driven calcite precipitation and the addition of superabsorbent polymers (SAP) into the concrete matrix.Firstly, the paper compares the absorption rate of SAP in various solutions, including a nutrient-based solution which is used in the bio-concrete. The results showthat the ionic composition of the liquid influence theswelling capacity greatly. In this study, the absorption rate of SAP in thenutrient-based solution is as low as 6% of the rate in distilled water. Thus, this finding could indicate a possible drawback of the combination of the proposed self-healing approaches. Further, this paper determines the impact of the SAP addition to cement paste with different water/cement ratios. In this experiment, the SAP is applied in various dosages(1% and 0.5% by c. w.)and states (a dry state or a fully swollen state).The conducted flowability and mechanical properties tests indicatea profound, generally negative, impact of the SAP addition on the cement paste characteristics. The paper then discusses possible adjustments of the SAP-cement pastecompositionand comparesthe present results with previous studies.