Abstract

Hindering water permeation through concrete under a hydrostatic pressure requires pore blocking by hydrophilic and/or hygroscopic crystals while hindering capillary absorption requires pore lining using hydrophobic materials. Multi–effect waterproofing (WP) materials that can combine these functions can provide integrated solutions for concrete durability problems. The multi–crystallization enhancer (MCE) is an aqueous solution that is added directly to concrete mixture at the time of batching then develops its WP and durability functions during the typical concrete curing process. The MCE system includes hygroscopic, hydrophilic, and hydrophobic constituents. This chapter describes physicochemical actions and mechanisms of the MCE and the associated structural changes. It then details effects of the MCE on concrete curing at normal and extreme conditions and strength development. It also demonstrates the effect of the MCE on the concrete durability highlighting its role in managing the thermal effects, reducing chloride ion penetration, and mitigating alkali−silica reactions.