Effect of Cold Temperatures on Performance of Concrete under Impact Loading

Abstract

This study investigated the effect of cold temperatures on impact resistance and mechanical properties of a number of self-consolidating and vibrated concretes. Different mixture compositions were developed and tested under compression, four-point bending, and drop-weight impact loading. All tests were conducted at four different temperatures: +20°C, 0°C, −10°C, and −20°C. The studied variables were supplementary cementing materials (SCMs) [including fly ash (FA), slag (SL), silica fume (SF), and metakaolin (MK)]; the nominal maximum coarse aggregate size (10 and 20 mm), coarse-to-fine (C/F) aggregate ratio (0.7 and 2), and binder content (250 and 500 kg/m3). In addition, 35-mm steel fibers were introduced in one self-consolidating concrete (SCC) mixture for comparison. The experimental results indicated that the compressive strength, flexural strength, and impact resistance of all developed mixtures were generally improved as the temperature decreased. These improvements were more pronounced in mixtures with a relatively low binder content of 250 kg/m3 and mixtures with a higher C/F aggregate ratio. On the other hand, the lowest improvements were observed in higher strength mixtures and mixtures with more reactive SCMs such as SF or MK. Colder temperatures also boosted the role of fibers in improving the flexural strength and impact resistance of concrete.