PRODUCTION AND USE OF SUBSTITUTE MATERIAL FOR SAND

摘要

PROBLEM TO BE SOLVED: To produce a substitute material for sand, which has superior properties than those of sand or improved soil and is used for foundation or buried object protection, from concrete fine pieces or fine powder, i.e., a kind of industrial waste, soil due to construction, i.e., a construction byproduct, or the like. SOLUTION: This production process of such a substitute material for sand involves subjecting raw material particles to surface modification treatment, to impart the raw material particles with water repellency and to eliminate defects of the particles, and more specifically, comprises: spraying 1 t of a raw material consisting of concrete fine pieces or fine powder, soil due to construction, or a mixture of them, with a liquid prepared by agitating 5 l of a reactive silicone formed by substituting a part of methyl groups of a dimethyl silicone with hydrogen atoms, 1 l of an ordinary dimethyl silicone and 4 l of water together; and rotating the sprayed raw material in a rotary drum while blowing hot air of about 100 deg.C into the rotary drum, to mix the material and to produce the objective substitute material; wherein the rotational speed and rotation time are adjusted to 8-10 rpm and >=30 min, respectively. In the process, although an about 15 min rotation time is sufficient for the purpose of only mixing, since such substitute material particles having somewhat uniform spherical shapes are preferred for the purpose of buried object protection, the rotation time is set longer. Also, the water content of the raw material is adjusted to about 5%.