Improving the rheological properties of concrete mixtures by adding polyethylene oxide

Abstract

1. Addition of polyethylene oxide (PEO) improves the rheological properties of concrete mixes: it increases their cohesiveness and homogeneity, reduces the water separation and segregation, and enables us to produce a mixture with a mobility which increases with time (up to 0.5–1.5 h) after preparation. The addition of PEO to high-mobility and casting concrete mixes is especially effective. 2. PEO can be added to a concrete mix in the form of a finely dispersed powder which is first mixed with cement, or as a solution in the mixing water. 3. The improvement of the rheological properties of the concrete mix depends on the dose of PEO, the molecular weight of the polymer, and the method of adding the additive to the concrete mix. It is best to add PEO with a molecular weight of over 3·106, to the extent of 0.005–0.1% (as a rule, 0.01–0.05%) of the weight of cement, in the form of a solution. 4. Addition of PEO has no practical effect on the mechanical properties of the concrete; however, it increases the homogeneity of its structure.