The purpose of this investigation was to examine what factors exert influence on the dynamic flexural strength of various mortar specimens, which was determined by a drop hammer testing apparatus.
The results obtained were summarized as follows:
(1) The dynamic flexural strength of mortar specimens increased up to the age of 7 days.
(2) When mortar specimens had the same static flexural strength, their dynamic flexural strength was hardly influenced by the ratio of sand to cement, S/C. For the specimens having the same S/C, the ones with a large ratio of water to cement W/C were stronger on dynamic flexural strength than the ones with a small W/C, even though the static flexural strength of the latter was large.
(3) The dynamic flexural strength was not interrelated to the static flexural strength, but interrelated to the first or the second kink point of the load-strain curve of bending specimens with a notch. The dynamic flexural strength depended on the magnitude of the energy absorbed till the first or the second kink point.