Experimental Study on the Rheological Properties of Fresh Foamed Cement Paste and Mortar

Abstract

Recently in Japan, foamed cement paste and foamed mortar have frequently been used as embankment material on soft ground because of their low unit weight, flowability, and ease of strength control. Conventional uses of these foamed materials include grouting for tunnel voids and for securing pipelines in tunnels. Since each material for foamed cement milk and foamed mortar have a different specific gravity, segregation can occur during mixing, pumping and placing. The mixture proportions of these foamed mixtures is very important, and are usually determined by trial and error. Experiments were carried out on the rheological properties of cement paste, mortar, foamed cement milk and foamed mortar. Compressive strength of these materials were also examined. Obtained results are as follows: (1) Plastic viscosity of foamed cement pastes or mortars are as same as that of cement pastes or mortars. (2) Yield value of foamed mixture decreases with addition of foam less than 30% by volume, and decrease with addition of foam more than 40%. (3) Relation between plastic viscosity and yield value is almost the same as mixtures without foam. (4) Compressive strength of foamed mixtures decreases with increase of foam content, and the tendancy is apparent in lower w/c.