Concrete Pavement Mixture Design and Analysis (MDA): Evaluation of Foam Drainage Test to Measure Air Void Stability in Concrete
The stability of air bubbles in fresh concrete can have a profound influence on the potential durability of the system, because excessive losses during placement and consolidation can compromise the ability of the mixture to resist freezing and thawing. The stability of air void systems developed by some air entraining admixtures (AEAs) could be affected by the presence of some polycarboxylate-based water reducing admixtures (WRAs). The foam drainage test provides a means of measuring the potential stability of air bubbles in a paste. A barrier to acceptance of the test was that there was little investigation of the correlation with field performance. The work reported here was a limited exercise seeking to observe the stability of a range of currently available AEA/WRA combinations in the foam drainage test; then, to take the best and the worst and observe their stabilities on concrete mixtures in the lab. Based on the data collected, the foam drainage test appears to identify stable combinations of AEA and WRA.
Identifying Incompatible Combinations of Concrete Materials: Volume II—Test Protocol
Unexpected interactions between otherwise acceptable ingredients in portland cement concrete are becoming increasingly common as cementitious systems become more complex and demands on the systems are more rigorous. Examples of incompatibilities are early stiffening or excessive retardation, potential for uncontrolled early-age cracking, and unstable or unacceptable air void systems. Several test methods have been reviewed to assess their usefulness in early detection of incompatibility, and thus prevent pavement field problems. A protocol has been developed to allow product manufacturers, concrete producers, contractors, and owners to monitor materials and concrete systems. The protocol has two phases: relatively simple field tests to provide early warnings of potential problems and central laboratory tests to support and confirm the field work.
Deterioration of Iowa Highway Concrete Pavements: A Petrographic Study
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