Study of a Method of Immediate Estimation of Concrete Strength
Appears on pages(s):
acclerated tests;accelerating agents;aeration;coefficant of variation; compression tests;compressive strength;field tests;fresh concretes;mortars (material);quality control;test equipment;water-cement ratio.
The method of immediate estimation of concrete strength using rapid hardening process is a method which can estimate concrete strength within about 1.5 hr after getting a sample from fresh concrete by means of compression test of rapidly hardened specimens. The rapidly hardened strength of specimens can be obtained by using the combination of addition of acceleraor and the high temperature curing. The strength of rapidly hardened mortar specimens which ae obtained by wet-screening of concree is clearly dependent on the water-cement ratio of onrete. Thus, there is high correlation between the 28-day strength of concrete and the strength of rapidly hardened mortar specimen. The coefficant of variation of the ratio of estimated strength at 1.5 hr to the actual 28-day strength of normal concretes was about 10 percent regardless of the brand of ordinary portland cement used in the laboratory test. Practiblity of this method was ascertained at the field test using a portable curing chamber and a compressive test apparatus.