Carbonation and chloride penetration of repair mortars with water treatment plant sludge and sugarcane bagasse ash sand

Water treatment plant sludge (WTPS) and sugarcane bagasse ash sand (SBAS) (wastes from water treatment and sugar/ethanol industries) can be used as replacements of natural sand in concrete. Thus, this paper aims to evaluate carbonation depth and chloride penetration of cementitious repair mortars produced with WTPS and SBAS. Three mortars compositions were analysed: plain reference sample (REF); sample with 3% of WTPS (3WTPS); and sample with 30% of SBAS (30SBAS). They were subjected to tests of accelerated carbonation and immersion in NaCl solution up to 84 days (12 weeks). The results showed that SBAS mortars had the best performance in relation to carbonation and chloride penetration tests. 3WTPS mortars had similar results to the reference sample. This is due to refinement of pores given by incorporation of fine waste materials making it difficult for aggressive agents to penetrate cement matrices. Therefore, 3WTPS and 30SBAS composites can be satisfactorily used in buildings repair services for more sustainable and durable construction

Application of super absorbent polymers (SAP) in concrete construction—update of RILEM state-of-the-art report

Superabsorbent polymers (SAP) are a new, promising class of chemical admixtures which offer new possibilities in respect of influencing the properties of cement-based materials in the fresh, hardening, and hardened states. Much research work has been done in the last two decades to set the stage for introducing this truly multipurpose agent into the practice of construction. In particular, three RILEM Technical Committees: 196-ICC, 225-SAP and 260-RSC contributed considerably to the related progress by coordinating and combining the efforts of international experts in the field. The major product of the RILEM TC 225-SAP work was the State-of-the-Art Report published in 2012. This comprehensive document covered all topics relevant to the application of SAP as a concrete admixture. Since then further important progress has been made in understanding the working mechanisms of SAP in concrete and the effects of SAP-addition on various concrete properties. The article at hand presents an update on the state-of-the-art and is the concluding document delivered by the RILEM TC 260-RSC