1989 年 38 巻 426 号 p. 268-274
The bending test and fracture toughness test with acoustic emission (AE) measurement were carried out on calcium-silicate/paper composites laminated with various spacings. The bending strength of the divider section specimen became twice as large as that of the calcium-silicate mortar (plain), while the bending strength of the arrester section specimen was 60% of that of the plain. Influence of the laminated specing on bending strength was hardly observed. The strength, however, was increased by producing the composite in which calcium-silicate penetrates in the fiber-structure space because of large adhesion between fiber and calcium silicate. On the fracture toughness test, J integral at maximum load, Jpmax, of the composites was approximately 30 times as large as that of the plain. The laminated spacing did not influence J integral at the on-set of calcium-silicate layer fracture nor J integral at the on-set of paper layer fracture. From the result of J-R curves determined by unloading compliance, on the other hand, the crack growth resistance increased with decreasing laminated spacing. A good correlation between the AE rating parameter, Tac=ΣEAE/B/ΔJ, and the crack growth resistance, ΔJ/Δa, was obtained. It is considered that most of the AE events having high energy were caused by the fiber pull-out and/or failure in paper layer. The high-energy AE relative frequency, RN, is an efficient parameter to predict the effect of reinforcement.