To obtain an artificial lightweight aggregate having high strength and low water absorption by adding a foaming agent and a tacky material to a specific vitreous raw material and burning and foaming the resultant granulated material and annealing the baked and foamed material.
A foaming agent in an amoung of 0.1-2.0 pts.wt. and 0.1-10.0 pts.wt. tacky material are added to 100 pts.wt. vitreous raw material having ≤100 μm maximum particle diameter, 10-20 μm average particle diameter and 0.7-1.2 particle size distribution (N value of Rosin-Rammler formula) and the mixture is granulated to afford a granulated material having 5-15 mm particle diameter. The granulated material is primarily burned at a temperature immediate before granulated material is fused and secondarily burned at such a temperature that the difference between a secondary burning temperature and a primary burning temperature becomes ≤100°C to foam the baked granulated material and then, annealed at a rage of ≤300°C/min until 800°C to provide an artificial lightweight aggregate having ≤100 μm maximum pore diameter, ≤100/mm2 pores having 1-100 μm pore diameter, ≥1,000 N crushing strength, ≤2.0% water absorption and ≤8.0% water absorption under pressure.
SUGAYA TOMOYUKI
SHIBATA TATSUMASA
HAYANO HIROYUKI
SUZUKI TAKAYUKI
MATSUSATO HIROAKI
