Design and evaluation of high-volume fly ash (HVFA) concrete mixes, report B : bond behavior of mild reinforcing steel in HVFA concrete.

PDFTech ReportTRyy1110Concrete constructionPortland cementFly ashMix designReinforced concreteRecycled materialsEconomic impactsCement additivesPerformance testsBond strength (Materials)MissouriMissouri. Dept. of TransportationMissouri University of Science and TechnologyNTL-HIGHWAY/ROAD TRANSPORTATION-DesignNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThe main objective of this study was to determine the effect on bond performanceof high-volume fly ash (HVFA) concrete. The HVFA concrete test program consisted ofcomparing the bond performance of two concrete mix designs with 70% cementreplacement with Class C fly ash relative to a Missouri Department of Transportation(MoDOT) standard mix design.Two test methods were used for bond strength comparisons. The first was a directpull-out test based on the RILEM 7-II-128 \ue2\u20ac\u153RC6: Bond test for reinforcing steel. 1. Pullouttest\ue2\u20ac? (RILEM, 1994). The direct pull-out tests were performed on specimens with #4(#13) and #6 (#19) deformed reinforcing bars.The second test method consisted of a full-scale beam splice test specimensubjected to a four-point loading until failure of the splice. This test method is a non-ASTM test procedure that is generally accepted as the most realistic test method for bothdevelopment and splice length. The beam splice tests were performed on beams with #6(#19) reinforcing bars spliced at midspan at a specific length to ensure bond failureoccurred prior to shear or flexural failure.Analysis of the HVFA concrete test data indicates that using greater than 50%replacement of cement with fly ash in concrete does not result in any increase in therequired development length of mild reinforcing steel