Reducing concrete porosity using supplementary cementitious material (white slag)

This research aims at assessing the utility of the white slag as a secondary cementitious material in decreasing the porosity of concrete and enhancing the overall performance. As sustainable construction enjoys growing popularity, the industrial by-products like white slag prove to be a possible alternative to the partial replacement of the Ordinary Portland Cement. The concrete mixes were prepared with the replacement rates of white slag of 0, 5, 10, 15, and 20 percent using the same amount of water-cement ratio of 0.45. Cube, cylinder, and prism specimens were 7, 14 and 28 days cast and cured to study the effect of replacement with time. Mechanical properties such as compressive strength, split tensile strength, and flexural strength were also tested and water absorption was tested to determine the porosity. The findings showed that the mix with 10 percent white slag had the biggest improvement with the compressive strength of 29.0 MPa in 28 days, which was a 16 percent increment over the control mix (25.0 MPa). The water uptake of 4.5% in the control reduced to 3.9% in 10% replacement and this revealed a 13% decrease in porosity. These results validate that replacement with moderate levels of white slag improves strength and durability, and can be used in the development of sustainable cementitious material.