The combined effect of using recycled coarse aggregate and well water on normal concrete

Abstract

The reuse of materials from destroyed structures as recycled aggregate for concrete has become an important issue, especially in Iraq’s Mosul City following the war of 2017. Many water types which are unacceptable for drinking, such as the well water available in Mosul, may be used in concrete, avoiding the need to use precious potable water. In this study, the effects of non-potable well water and recycled coarse aggregate on the mechanical properties of normal concrete (compressive, splitting, and flexural strength) and the effects of using well water on the compressive strength of mortar were investigated. Several concrete mixes were prepared: a reference mix using natural coarse aggregate and potable water, mixes using recycled coarse aggregate with and without well water, and one using natural coarse aggregate and well water. The concrete specimens were cured and tested for compressive, splitting, and flexural strengths with both types of water (well and potable) used as mixing and curing water. The compressive strength of concrete was lower by about 7.5% when well water was used with natural coarse aggregate; approximately, a 19% decrease in compressive strength was observed when recycled coarse aggregate was used with well water. The flexural and splitting tensile strengths also decreased with well water, while the values of these properties increased when recycled coarse aggregate was used.