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, T
ac=
ΣEAE/
B/Δ
J, and the crack growth resistance, Δ
J/Δ
a, 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.
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