Technical Questions

ACI Committees, Membership, and Staff have answered common questions on a variety of concrete related topics.



Do some water-reducing admixtures induce bleeding?

Q. Do some water-reducing admixtures induce bleeding?

 

A. Yes, some do, and this may be beneficial in concrete for flatwork in a hot, arid climate by minimizing plastic shrinkage. Bleeding is the rise of the mixing water in newly placed concrete. Plastic shrinkage occurs when the rate of evaporation exceeds the rate of bleeding. Bleeding may reduce strength and increase permeability if the bleed water is worked into the surface. Bleed water lost by evaporation reduces the w/cm and raises the strength of concrete.

 

References: SP-1(02); E4-12; ACI 212.3R-16; SP-288; ASTM C494; ASTM C1017

Topics in Concrete: Admixture; Concrete Fundamentals; Materials

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