PURPOSE: To obtain the title compsn. having heat resistance and strength and capable of being sent by a pump by using a general cellulosic thickener in place of a thickener in a compsn. composed of hydraulic cement, lightweight aggregate and ethylhydroxyethylcellulose as the thickener and adding a specified foaming agent.

CONSTITUTION: A flowable compsn. is composed of 100kg hydraulic cement, 0.1-10kg cellulosic thickener having no acid radicals and/or PVA and 0.01-5wt.% one or more kinds of foaming agents basing on the amt. of the cement. The foaming agents are selected among sulfuric ester, sulfonate, polyoxyethylene alkyl ether and polyoxyethylene alkylphenyl ether. Lightweight aggregate having ≤0.6g/cm3 bulk density is then added to the flowable compsn. by 0.3-1.5m3 per 100kg of the cement to obtain a compsn. for a lightweight body. In this compsn., the extraordinarily large amt. of the lightweight aggregate can be kneaded with a small amt. of a binder.