Using citric acid as an admixture and it's influence on some properties of concrete

Abstract EN

The objective of this investigation is to find the effectiveness of the citric acid as retarding admixture.

The experimental results indicate that the optimum dosage of citric acid is 0.02% by weight of cement.

This dosage causes a delay in initial and final setting time of 1: 42 and 3:18 hour : minute, respectively ; and a reduction in water-cement ratio of 13% relative to reference concrete mix.

So, citric acid can be classified according to ASTM-C494 as water-reducing and retarding chemical admixture type D.

The investigation also extends to evaluate the effect of using citric acid on properties of concrete such as, compressive strength, splitting tensile strength, modulus of rupture and dynamic modulus of elasticity at normal conditions and after exposure to salt solutions.

Generally the results indicate that using citric acid in concrete enhance it's properties at normal conditions, the percentage increase in compressive strength, splitting tensile strength, modulus of rupture and dynamic modulus of elasticity at age 180 days was about 56%, 13%, 24% and 8% respectively relative to reference concrete.

Also it was observed that concrete containing citric acid has good performance after 180 days exposure to salt solution in comparison with reference concrete.