Experimental and statistical studies of using wash water from ready-mix concrete trucks and a batching plant in the production of fresh concrete

• Concrete wash water decreased the setting time of hydraulic cement.
• Concrete wash water abated the compressive strength of hydraulic cement mortars.
• Super plasticizer admixture and micro silica caused an increase tensile strength.
• The workability of all the samples varied between 12 cm and 15 cm.
• The wash water did not change the strengths of the concrete samples, strikingly.

We studied experimentally and statistically the feasibility of using concrete wash water in the production of fresh concrete. The setting time of hydraulic cement and the compressive strength of the hydraulic cement mortars were acceptable. In the framework of 54 mix designs and using various mixes of tap water and concrete wash water, we produced concrete samples to assess the characteristics of the samples. The workability and penetration depth of all the samples were allowable. We used an analysis of variance (ANOVA) technique to analyze the tensile, flexural and compressive strengths which indicated the concrete wash water did not alter the strengths significantly.