Environmental and economic sustainability of crack mitigation in reinforced concrete with SuperAbsorbent polymers (SAPs)

Due to the increasing awareness and sensitivity towards the environmental and economic sustainability issues, the concrete industry has to deliver innovative solutions, in terms of materials, products and structural concepts, to achieve higher durability of engineering feats in real service scenarios. The inclusion of SuperAbsorbent Polymers (SAPs) into the concrete mix, can not only stimulate the autogenous crack healing, but is also able to reduce the shrinkage cracking through internal curing. In this paper, Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analysis have been performed to assess both the ecological and economic profile, in real scale, of conventional reinforced concrete structures, made with concrete containing SAPs, in comparison to a reference solution without any addition. For this purpose, the corrosion of reinforcement has been regarded as the main degradation mechanism and different corrosion models have been considered and combined with the structural analysis principles to obtain reliable Service Life (SL) estimations. Four different scenarios, with a SL ranging from 50 up to 100 years, have been analyzed to assess the potential benefits of a wall, cast with SAP-containing concrete (Wall_SAP). Both Wall_SAP and a reference wall without SAP (Wall_Ref) are subjected to the concrete cover replacement as main maintenance activity while for the Wall_Ref also the crack filling by means of polyurethane resin is considered as an option (Wall_Resin). The adopted CML impact-assessment method, developed by the Center of Environmental Science of Leiden University, shows the advantage of using SAPs, since the environmental burdens were reduced up to 20% in the case of Fresh Water Aquatic Ecotoxicity impact category in comparison to the reference for the fourth scenario. In this scenario a hemispherical corrosion pit model for the steel bars and a service life of 100 years were taken into account. Furthermore, the economic assessment developed for the same scenario, pointed out for the SAPs based solution, there identified as Wall_SAP_M2_100, a consistent reduction in terms of costs up to 14% if compared to the reference, there named as Wall_Ref_M2_100. The outcomes definitely highlight the potential of the analyzed technology that can fulfil the future needs of the stakeholders involved in the construction sector.