Abstract
The control of the water content per unit volume of concrete, which greatly affects the product’s strength and durability, has come to be highly required in order to stabilize the production quality.
Also it is obliged by Government Issue to estimate the water content per unit volume of concrete in construction of a building lager than 1500m2 total floor space. The current air meter method has the problem in estimation accuracy, though it is easy and requires less time. We have worked out the new way of improving accuracy of the air meter method by adding some measurement procedures and newly equation for estimate. The measurement was added the procedure for measuring the mass of coarse aggregate dug up from the sample after the air content and mass were measured. The estimated equation has the feature that the sampling error of the examination can be corrected, and the water content per unit volume of concrete can be presumed even with concrete different from the specified mix proportion. This newly developed estimation by the unit water content method has proved, by verified results of both the laboratory and the field experiment, to have higher accuracy than former air entrainment meter method. It also proved that the unit water content could be presumed in the same degree of accuracy as the high frequency heating dryness method.
