一定荷重下におけるセメントモルタルばりの破壊時間に関する二, 三の実験

抄録

The present report gives data on the fracturing time of cement mortar beam under sustained load.
It is well known that the density function of transition probability of fracture in glass and polycrystalline metals shows constant value regardless of t. That is, the relation between in P(t) and t is linear. Where P(t) denotes the probability that the fracture of specimens does not occurred until the time of t.
On the contrary, the data obtained from this investigation show that the density function of transition probability of fracture in cement mortar is not constant. That is, the relation between lnP(t) and t is not linear. It appears that the microcracks developed in cement paste under sustained load are responsible for the nonlinear relation.
In this report, the effects of preloading, humidity of the air and moisture in specimen on the fracturing time are also shown, The preloading delays the fracture of cement mortar. The moisture in the air or in specimen delays the fracture immediately after loading but promotes the fracture after a certain time. It seems that these phenomena are also caused by the microcracks developed in cement paste.