Effect of drying and water supplying after drying on tensile strength of cement mortar

The influence of drying and water supplying after drying on flexural strength of cement paste is investigated and some considerations are given examining the crack with an electron microscope. It is concluded that a great number of cracks which is about 0.01 mm wide are occurred due to drying for 1 day under constant relative humidity (R.H.) 43%, and they reduce the tensile strength of the specimen about 1/3 times lower than that of a sound specimen. Water curing for about 3 hours after drying repairs the cracks and the flexural strength is almost recovered. (author)