Study On Durability Of Low-heat Portland Cement Concrete Under Simulated Marine Environment

With the continuous development of marine resources, marine engineering has been vigorously built, while seawater on the structure of the corrosive and destructive issues have become increasingly prominent.Foreign large-scale construction started earlier, it took a long time to realize the seriousness of the concrete building damage, so more and more attention to the durability of concrete problems.In the past, China is not enough attention to the durability of concrete problems.With the rapid economic development, a large number of infrastructure construction, concrete durability problems continue to highlight.In this paper, the corrosion resistance of low heat Portland cement against seawater is studied by contrast analysis of different cement.The XRD and SEM are used to analyze the changes of micro-structure and morphology of the samples after the erosion, and also the seawater erosion mechanism is analyzed. The corrosion resistance coefficient is used as the evaluation standards of corrosion resistance. The results show that the corrosion resistance low heat Portland cement is better than medium heat Portland cement, and ordinary acid Portland cement is the worst. The corrosion resistance of cement is closely related to its mineral composition. Calcium hydroxide is the product of the hydration reaction of Portland cement, which reacts with sulfate to form gypsum and expansion failure occurred. Tricalcium aluminate reacts with calcium hydroxide to form ettringite and expansion failure occurred. The erosion resistance of tricalcium silicate is poor which produces a large amount of calcium hydroxide by hydration reaction, which is the raw material of the erosion reaction. Calcium silicate hydrate produced less calcium hydroxide, so the corrosion resistance of calcium silicate is better than tricalcium silicate.The durability of concrete is the focus of this paper. The mechanical properties, thermal properties, erosion resistance and volume stability of concrete under seawater erosion are studied through a large number of concrete contrast tests. The results show that the low heat Portland cement concrete has good erosion resistance, compactness and frost resistance, and which can ensure the concrete can resist seawater erosion in the marine environment. At the same time, excellent impact wear resistance, deformation properties and volume stability,which make the structure of concrete is more stable which is an important factor of erosion resistance of concrete. Therefore, low heat Portland cement concrete in the marine environment with better durability.