Title:
Field Measurement of Water-Cementitious Material Ratio Using Nuclear Gage
Author(s):
Amy M. Dowell and Steven M. Cramer
Publication:
Materials Journal
Volume:
100
Issue:
6
Appears on pages(s):
485-491
Keywords:
cement; water; water-cement ratio
DOI:
10.14359/12955
Date:
11/1/2003
Abstract:
A method that accurately provides for the real-time determination of the water-cementitious material ratio (w/cm) of concrete in the field would be of great use to the concrete pavement industry. Recently there has been discussion within technical committees at ASTM International on the development of a standard for the nuclear water-cement gage. This gage was tested in the field and laboratory to assess its capabilities to measure w/cm. Seven concrete paving sites were visited and the concrete tested. Materials from these paving sites were returned to the laboratory for calibration of the nuclear gage. Repeat tests were conducted to determine the inherent variability of the instrument. Promising results were obtained with concrete mixtures containing limestone aggregates but errors were large when the gage was used with mixtures containing igneous aggregates. Field errors with both aggregate types were higher than those in the laboratory and were thought to be due to batching and sampling variations.