Low-temperature (?10 °C) curing of Portland cement paste – Synergetic effects of chloride-free antifreeze admixture, C–S–H seeds, and room-temperature pre-curing

Cold weather drastically shortens the construction season in northern regions. Low ambient temperatures are known to have detrimental impacts on reactivity and hardened performance of cementitious materials. This study therefore aims assess combined calcium silicate hydrate (C–S–H) seeds, binary chloride-free antifreeze admixture (i.e., urea nitrate), short-period precuring at room temperature (23 ± 1 °C) ordinary Portland cement (OPC) paste-cured ?10 °C. The heat hydration, setting time, compressive strength, freezing point, frozen water amount, hydration products precipitation rate, absorption, permeable porosity were investigated experimentally. best results terms degree obtained when C–S–H admixture, due their mutual impacts. In absence room-temperature precuring, seeds additive showed negligible acceleration strength development subzero-cured paste. incorporation decreased points binders thus protected admixed against frost damage, effects more obvious with a few hours precuring. 28 d-old OPC paste modified by treated developed rapidly °C, gaining 96% (75.1 MPa) that measured control cured (78 MPa), comparable durability properties significant reduction energy consumption CO2 emissions.