The effect of elevated temperature on the steel reinforcement in lightweight concrete

• Main Authors: Cheung, Edmund C., Lim, Frederick C., Lim, Xavier S.
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Concrete > Effect of temperature on; Concrete > Testing; Lightweight concrete; Materials at high temperatures; Composite reinforced concrete
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7086
• Institution: De La Salle University

This study is focused on the effect of elevated temperature on steel reinforcement in lightweight concrete. Mt. Pinatubo aggregates were used for this study. The design strength of lightweight concrete was limited to 20MPa. A total of 9 cylindrical and 12 rectangular prism specimens were casted and cured for at least 28 days. Prisms contained steel reinforcement of 8, 16, and 25 mm, having 40 mm cover. Concrete specimens were heated to 900C for 1, 2, and 3 hour duration at the Heat Treatment Facility inside the MIRDC compound and were cooled for a period of time. The prisms were destroyed to retrieve the steel reinforcement for tension testing. The data retrieved from the testing of steel reinforcement were analyzed and compared to that from the study of Ong et al (2006) for normal weight concrete. Data for comparison included yield and tensile strength of steel reinforcement and compressive strength of concrete from this study and the study of Ong et al (2006). Findings reveal that the compressive strength of lightweight concrete did not improve as compared to normal weight concrete when exposed to elevated temperature. The remaining strength was 9.75% and 10.90% from lightweight concrete and normal weight concrete respectively when exposed to 900C. However, the ability of lightweight concrete to protect steel reinforcement was significantly higher than that of normal weight concrete. This was reflected with losses on yield and tensile strength of 12.8% and 6% respectively for 16 mm steel reinforcement in lightweight concrete, as compared to 36.6% and 30.1% respectively in normal weight concrete. In addition, yield and tensile losses for 25 mm steel reinforcement in lightweight concrete incurred 8.2% and 8.9% respectively as compared with 21.65% and 18.7% respectively from normal weight concrete.