Effect of w/c ratio and antifreeze admixture on the frost damage of sulfoaluminate cement concrete at − 20 °C

Abstract

• The free water contents in SAC paste at −20 °C were tested. • The early volume deformation of SAC concretes at −20 °C were investigated. • Calcium nitrate showed better anti-freezing protection than urea. The effects of different water/cement ratios and antifreeze types on the frost damage of sulfoaluminate cement (SAC)-based materials exposed to −20 °C were studied. The results showed that the early frost damage of SAC mortar was closely related to the ice content which could be reduced by reducing the water/cement ratio and adding calcium nitrate. The early volume deformation rule of SAC concrete is different from that of Portland cement concrete, which is mainly attributed to the rapid hydration of the cement during the melting stage. The introduction of antifreeze admixtures, especially urea, has a relatively large negative impact on the anti-freezing–thawing performance (-18 °C − 5 °C) of SAC concrete.