A Study On The Durability Of Desalinated Sea Sand Concrete

Many countries in the world have been being actively engaged in the development of urbanization in past decades. The shortage of river sand resources has gradually become an imminent problem. In order to alleviate the shortage of river sand in construction, as the advantages of abundance, convenience and low-cost, sea sand resources gradually become the focus of attention of every country. With a cooperative project of the Dunkerque Port Authority, this article examines simply the first batch of desalinated sea sand produced by Dunerque Port through some physical tests, mechanical tests and pays more attention to research and evaluate some durability performances of this desalinated sea sand.This project selected sea sand produced by French Colas Group as standard sand, which meets the international ISO standards and EU norms. Through comparison of Dunkerque sea sand’s and standard sand’s performances during different tests, this article can be divided into four parts. Firstly, we test many Dunkerque sea sand’s and standard sand’s properties, which are particle size distribution and fineness modulus, apparent density and bulk density, sand’s robust performance, sand’s angular performance, clay content, shell content, chloride ions content, three points flexural strength and compressive strength and porosity. The results show that the Dunkerque desalinated sea sand’s physical properties and mechanical properties are slightly worse than standard sand, but it comply with the requirements of the concrete construction. Secondly, through the rapid carbonation test, we compared the desalinated sea sand’s and standard sand’s carbonation performance under different relative humidity conditions. Experimental results show that the carbonation reaction speed of desalinated sea sand mortar specimens is faster than the standard sand mortar specimens’carbonation reaction when the relative humidity in the environment is greater than20%. Then we do the RCT rapid chloride penetration test to conclude that desalinated sea sand mortar has a higher surface and internal concentration of chloride ions than standard sand mortar, which verifies the desalinated sea sand is more susceptible to penetration of chloride ions than standard sand mortar. The capability of chloride ions binding test shows that extravagation chloride ions binding capacity has nothing to do with the type of aggregates and mixed chloride ions binding capacity is directly related to aggregates’ chloride ions content. Finally, through the first test of rapid alkali-silica reaction and the retrial test of long-term alkali-silica reaction, we confirm that Dunkerque desalinated sea sand does not have the potential hazards of alkali-silica reaction.