Durability and Performance of Novel Concrete-Cenosphere Composites in Extreme Environments

摘要

A study has been conducted to further understand the performance of a lightweight concrete containing cenospheres instead of sand as the fine aggregate. Specifically the strength at low temperature, resistance to repeated freeze-thaw cycles and the effect of silane coating on cenosphere in concrete were investigated. The study is a continuation of a previous research project titled 'Processing and Characterization of a Lightweight Concrete using Cenospheres' in which a lightweight concrete was processed by replacing sand with cenospheres on a volume basis. The admixture silica fume was used (7%) to help enhance the interfacial properties between the cenospheres and cement matrix. The mechanical properties including compressive strength, tensile strength, flexural strength and fracture toughness were tested at 0 deg C. The compressive strength increased by 30% at 0 deg C when compared to the room temperature value. Virtually no deterioration was found after 300 freeze-thaw cycles. The moisture absorption capacity of cenospheres was observed to be 18-times greater than sand used in normal concrete. Water absorption by cenosphere concrete was greater than the normal concrete. Drying phenomenon of cenospheres, sand, cenosphere concrete and the normal concrete was also studied.