ABSTRACT
Concrete structures in alpine-cold regions of western China are under the combined effects of sulfate attack and freezing-thawing cycles all year round, with significant durability problems. Based on a highway project and the quadratic general rotary design method, this paper studies the influence pattern of four factors, i.e., fly ash, slag, coarse aggregate and water-cementitious ratio, on the relatively dynamic elastic modulus and mass loss rate of concrete under the coupled sulfate-freeze-thaw environment. The results show that fly ash and slag could help to improve the denseness of microstructure and the sulfate-freeze-thaw resistance of concrete and that the degree and pattern of influence of these four factors on durability are subject to the circumstances. The optimum sulfate-freeze-thaw resistance can be obtained when the fly ash admixture is 32%, the slag admixture is 19%, the coarse aggregate volume ratio is 0.34, and the water-cementitious ratio is 0.4.
