Investigation of freeze-thaw mechanism for crumb rubber concrete by the online strain sensor

Abstract

Deep understanding on the frost resistance of crumb rubber concretes (CRC) is very important for the CRC design. In this study, in order to record the internal strain during the whole freeze–thaw process, an on-site strain monitoring is achieved with a vibrating wire strain sensor. By doing so, the internal microstructure variations including the micromorphology and pore as well are studied based on the mass loss rate and relative dynamic elastic modulus variation. The frost damage of concrete in each freeze–thaw cycle involves four stages: big pores freeze, small pores freeze, water adsorption resistance and ice-thawing stage. Meanwhile, it is found that the crumb rubber acts as a regulating valve during the freeze–thaw cycle, by (i) reducing the frost heaving pressure in the freezing process, and (ii) inhibiting exterior water invasion in the thawing process. This can be helpful for the design of the CRC with outstanding frost resistance.