OPTIMUM COMPONENTS AND PROPORTIONS FOR SELF COMPACTING CONCRETE IN SULFATES ENVIRONMENT

Abstract

The purpose of this paper was to know more about self-compacting concrete (SCC) in sever sulfate environment compared with its reference vibrated concrete (VC) with similar mixes proportions of SCC for different ages up to 400 days. Such tests can be more reliable in evaluating emerging concrete types such as self consolidating concrete (SCC). Several applications of SCC involve its exposure to both freezing– thawing cycles and chemical attack, particularly to sulfate-rich media. Sixteen mixes of SCC and VC were therefore made with the same raw materials with changing some factors in the mix such as: cement content, coarse to fine aggregates proportions, coarse aggregate size, coarse aggregate type and cement type. After 28 days of potable water curing, a standard compressive tests was carried out for all samples of both SCC and VC then they were immerged in sodium sulfates solution with 5% concentration according to (ASTMC 1012). The specimens were cyclically exposed to 5% Na2SO4 solution and air every alternate 5 days after 28 days curing by potable water. Age factor till 400 days have been also considered in this research. In addition, fresh properties of SCC and VC are recorded for all concrete mixes. The results of this research show that the compressive strength for SCC mix gave a significant reliable results compared with VC where all subjected to a cyclic immersion in 5% sodium sulfates. However, more factors in the component of SCC mixes. Factors such as cement content and type, aggregate type, size and ratio and powder type were studied for SCC component. Results indicated that SCC exhibited more residual strength compared with VC especially utilizing high cement content of Sulfate Resistance Cement (SRC) type, basalt as coarse aggregate, with maximum nominal size 10 mm with ratio coarse to fine aggregate (C/F) =0.35:0.65 utilizing Silica Fume (SF) type in addition to superplastisizer and viscosity enhancement admixture VEA.