Investigation on Estimation Method for Water Content of Fresh Concrete Using Scattering-Type Neutron Moisture Meter

Abstract

In order to assure high accuracy in estimation of water content of fresh concrete by the neutron moisture meter, the establishment of a suitable calibration curve is the most important. In this study, fine aggregate containing the required amount of water in a container with fixed capacity is measured with the scattering-type neutron moisture meter. And the calibration curve is obtained from the relationship between the measured neutron counting and the amount of water added to fine aggregate. The kind of fine aggregate hardly influences the neutron counting. The neutron counting becomes large with the increase of particle size of fine aggregate, even when added water amount is the same. However, use of fine aggregate not less than 2.50 in fineness modulus dose not noticeably affect the neutron counting. The method with calibration curve using fine aggregate can evaluate the water content of fresh concrete with a good accuracy.