Impacts of workability on properties of concrete at subzero temperature

In winter concrete construction in China, anti-freezing admixture is usually added into concrete to guarantee the strength development of concrete at subzero temperatures. The slump of concrete with anti-freezing admixture is usually controlled at (30 ± 10) mm according to JC475-92. However, more and more high-slump concrete or self-compacting concrete are being applied in winter concrete construction. Therefore, in this paper, the strength of concrete with and without anti-freezing admixture al different slumps was investigated. When water cement ratio was fixed and superplasticizer was used to increase the slump, the strength difference of concrete at normal temperature can be neglected, but the concrete strength difference at subzero temperature is quite significant. The strength of concrete with anti-freezing admixture decreased with the increase of slump of concrete. The reason may be that superplasticizer extended the setting time and result in frost damage of concrete at early age.