Abstract
The author's sound velocity method and its application for determinating the sound velocity in concrete were described in the Transactions of the Architectural Institute of Japan, No. 51. In this paper the relations between the variation of sound velocity in mortar specimens and the compressive strength are considered under various conditions and ages of curing. In computing the dynamic modulus of elasticity from the measured longitudinal sound velocity based on well known relationships, it is necessary to correct the value of the modulus with a factor which depends on the sectional shape of the specimen, and the factor is obtained in this paper from the experimental results of velocity and (sonic) vibration measurements for specimens with some typical sectional shapes. The relations between the static modulus of elasticity and the dynamic modulus computed from the resonating sound velocity are also presented. It is found, however, that these two moduli do not necessary agree wtth each other. It is shown that the effect of the moisture content of a specimen on the sound velocity is insignificant whether the specimen is saturated or in dried condition at the time of test, whereas the water contained in the mortar has considerable influence on the dynamic modulus of elasticity measured by the sound velocity method.
