CONSTRUCTION OF CRACK-FREE BRIDGE DECKS TRANSPORTATION POOLED FUND STUDY

i The effects of paste volume, water-cement ratio, aggregate type, cement type, curing period, and the use of mineral admixtures and superplasticizers on the free shrinkage of concrete are evaluated with the goal of establishing guidelines to reduce cracking in reinforced concrete bridge decks. Three concrete prisms were cast and tested in accordance with ASTM C 157 for each mixture up to an age of 365 days under controlled conditions of 23 ± 2°C (73 ± 3°F) and 50 ± 4 percent relative humidity. The work was organized in five test programs. The first program included mixes with water-cement ratios of 0.40, 0.45, and 0.50, and aggregate contents of 60, 70, and 80 percent, with Type I/II cement and Type II coarse-ground cement. The second program included the mixes with one of three coarse aggregate types, granite, limestone, and quartzite. The third program evaluated the effects of Class C fly ash, ground granulated blast-furnace slag, and silica fume as partial volume replacements for portland cement. The fourth and fifth programs were used, respectively, t