Abstract
The subject of this paper is to introduce on the early properties of concrete from placing to three-day in 20°C curing mainly for ordinary portland cement, and the term of early age is varied with speed of setting and hardening of cement.
The early properties of concrete consist of five groups as follows :
(1) Setting : Introduced the testing method of setting for concrete up to date and explained a study of setting and hardening of concrete by author.
(2) Bleeding, Early volume change and Cracking : Bleeding (effect on bleeding of concrete by materials, mix, form, placing), Early volume change (sedimentation, early shrinkage of cement paste, mortar and concrete) and Early cracking (expranation to early occurence of cracking for concrete).
(3) Early compressive property : The method of estimation for early compressive strength of concrete by author, modulus of elasticity, examples of application.
(4) Early tensile property : Testing method of tensile stress-strain curve.
(5) Other early properties of concrete mentioned above : Effect of freezing, drying, vibration, curing temperature at ealy hardened concrete, erossion in water and salt permeation at early age.
