Enhanced durability performance of cracked and uncracked concrete by means of smart in-house developed superabsorbent polymers with alkali-stable and -unstable crosslinkers

For the past two decades, research on the use of superabsorbent polymers (SAPs) in cementitious mate-rials has proven that these innovative materials have the potential to become a suitable admixture in the concrete industry. Not until recently, most of the applications studied made use of SAPs originally designed to be used in other industries, such as in food, agricultural and hygiene products. In this paper, an innovative "in-house" developed SAP (SAPX) is presented, designed with a double crosslinking system specifically for applications in concrete structures. Its efficiency is compared with two commercially available SAPs (SAP1 and SAP2) for different applications. The "in-house" developed SAP promoted an immediate sealing effect of cracked concrete specimens as reflected by a reduction of 72% in the water permeability of specimens with cracks up to 250 um compared to specimens without SAPs. A superior performance was also found against frost attack in salt scaling after 28 cycles of freezing and thawing. Although no complete mitigation of shrinkage was noticed, SAPX promoted a significant reduction in the shrinkage strain at early ages and up to 28 days. In terms of mechanical properties, SAPX reduced the strength to a comparable extent as SAP1 and less than SAP2. To conclude, SAPX showed a better per-formance compared to the already commercialized SAPs and has a high potential towards large-scale production to be exploited for concrete applications. (c) 2021 Elsevier Ltd. All rights reserved.