Impact of Additives on the Split Tensile Strength of Roller Compacted Concrete

Abstract

Additives are implemented as partial replacement of Portland cement in concrete to enhance the required physical properties. In the present investigation, roller compacted concrete slab samples were prepared using gap and dense aggregate gradation. Three percentages of Portland cement were adopted, (16, 12, and 10) % by weight of aggregates. Three types of additives, (hydrated lime, fly ash, and fumed silica) were implemented as partial substitute of Portland cement. Core specimens have been obtained from the prepared slab samples and tested for indirect tensile strength. It was observed that dense gradation exhibits higher tensile strength than gap gradation by (35.6, 9, and 5.5) % for mixtures of (10, 12, and 16) % cement content. When the fumed silica additive was incorporated as partial replacement of cement, the indirect tensile strength of concrete declines by (2.7, 43.8, and 57.5) % and (36.8, 54.1, and 67.6) % for (10, 12, and 15) % replacement for gap and dense gradation respectively. The indirect tensile strength increases after the partial replacement of cement by lime for dense and gap graded mixtures by (187.8, 96.5, and 61.6) % and (260, 131, and 78.5) % for (5, 7, and 10) % replacement respectively. However, the tensile strength of concrete increases after the partial replacement of Portland cement by fly ash for gap and dense graded mixtures by (201, 77, and 24.2) % and (117, 45, and 16.5) % for (20, 30, and 40) % replacement respectively. Fly ash and Hydrated lime are recommended as additives for partial replacement of Portland cement in roller compacted concrete pavement from the indirect tensile strength point of view.

Keywords: Indirect Tensile Strength, Roller Compacted Concrete, Fly Ash, Additives, Lime, Fumed Silica