Durability analysis of self consolidating concrete used in the Stalnaker Run Bridge

Self-Consolidating Concrete (SCC) was used in the pre-tensioned box beams for the Stalnaker Run Bridge project in Elkin, WV. It was found that the SCC used in Stalnaker Run Bridge has a low freeze-thaw durability index. One of the SCC full-scale box beam was subjected to loading test at WVU structural laboratory until failure. Following the observed freeze-thaw behavior, this research study was proposed to quantify the SCC filling ability by saw-cutting the full-scale SCC test beam and to determine the cause of SCC beam\u27s low freeze-thaw durability using the air-void analysis. Results from the coarse aggregate distribution analysis of the saw-cut cross sections and the core specimens of the SCC test beam show that the SCC beam exhibited significant segregation behavior. An air void analysis of the core specimens shows a high specific surface and spacing factor (SF); especially, the observed SF is about twice of the 0.2 mm suggested by ASTM C666. Additionally, the cored SCC beam specimens failed at 270 cycles, not meeting the ASTM C666 freeze-thaw requirement of 300 cycles. The permeability of the SCC was determined using the Rapid Chloride Penetration Test (RCPT) [ASTM C1202]. The results of the RCPT suggest that specimens from the test beam exhibited moderate chloride ion penetrability, which values higher than the allowable value of 1,500 Coulombs.;Laboratory SCC specimens were reproduced using the same mix design as was used for the SCC test beam. The laboratory cast SCC also exhibited a poor air void structure but with higher compressive strength. In order to better understand the durability effect of high temperature curing of SCC, half of the new casting specimens were cured at a higher temperature (as experienced by the SCC test beam) while half of the specimens were cured at room temperature. The compressive strength of high temperature cured SCC was higher for the first 3 days but lower at the 28 days compared to the room temperature cured specimens. The results indicated that high temperature curing had significant effect on concrete freeze-thaw durability and RCPT penetrability. The high temperature cured specimens failed at 270 freeze-thaw cycles while the room temperature specimens survived the 300 freeze-thaw cycles