Studying the Effect of Internal Sulfates on Normal and Lightweight Concrete

Abstract

The current research includes study the effect of internal sulfate (Calcium sulfate) on mechanical properties of normal and light weight concrete. The mechanical properties included compressive, splitting tensile, and flexural strength. The experimental work consists of casting and testing 216 cubes (150×150×150) mm, 216 cylinders (200×100) mm, and 144 prisms (400×100×100) mm having different condition including: ratio of the sulfate, the age test, type of concrete, and type of cement. This research consists of two part normal and light weight concrete, each part divided to three groups according to type of cement (type I cement, type V cement, and type I cement with 15% silica fume replacing from weight of cement). Each group consisting of four set with different ratio of sulfate (0.28% (reference SO3), 0.5%, 1% and 1.5%) by weight of fine aggregate where these ratios approximate the actual reality of the sulfates present in internal concrete components such as sand, each set having nine cubes tested in a different age (28, 60, and 90) days. The experimental results show that the harmful effect of internal sulfate in concrete on mechanical properties was decreased by using type I cement with 15% silica fume replacement whether normal and light weight concrete. Using of silica fume concrete is more effective to enhance the concrete resistance to internal sulfate attack.