Quick and nondestructive determination of cure-state and water-to-cement (w/c) ratio in fresh Portland cement-based materials is an important issue in the construction industry since the compressive strength of these materials is significantly influenced by w/c ratio. In this paper, the results of a study demonstrating the potential for early determination of cure-state and w/c ratio of Portland cement-based materials, using a near-field microwave inspection technique, are presented. This technique utilizes the reflection properties of an open-ended rectangular waveguide probe radiating into Portland cement-based materials at 5 GHz (G-band) and 10 GHz (X-band). The results demonstrate the ability of near-field microwave sensing techniques to determine the state of hydration of cement paste and concrete with 0.50 and 0.60 w/c ratios and varying aggregate contents. An empirical formula relating the magnitude of reflection coefficient to the curing time is presented. Using this empirical relationship, the w/c ratio of cement paste and concrete can be unambiguously determined when daily monitoring of the reflection properties of the specimens is performed. The potential for utilizing this technique for on-site monitoring of cure-state and w/c ratio (and compressive strength) determination is also discussed.
K. J. Bois et al., "Cure-State Monitoring and Water-to-Cement Ratio Determination of Fresh Portland Cement-Based Materials using Near-Field Microwave Techniques," IEEE Transactions on Instrumentation and Measurement, vol. 47, no. 3, pp. 628-637, Institute of Electrical and Electronics Engineers (IEEE), Jun 1998.
The definitive version is available at http://dx.doi.org/10.1109/19.744313
Electrical and Computer Engineering
National Science Foundation (U.S.)
Electric Power Research Institute
Keywords and Phrases
10 GHz; 5 GHz; G-Band; X-Band; Cement Paste; Cements (Building Materials); Compressive Strength; Concrete; Condition Monitoring; Construction Industry; Cure-State Monitoring; Curing Time; Fresh Portland Cement-Based Materials; Hydration State; Inspection; Microwave Inspection Technique; Microwave Reflectometry; Moisture Measurement; Near-Field Microwave Techniques; Nondestructive Determination; Nondestructive Testing; Onsite Monitoring; Open-Ended Rectangular Waveguide Probe; Reflection Coefficient; Reflection Properties; Varying Aggregate Content; Water-To-Cement Ratio Determination; Water/Cement Ratio; Infrastructure Testing And Cement-Based Material Evaluation; Material Characterization
International Standard Serial Number (ISSN)
Article - Journal
© 1998 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.