Experimental evaluation of substitution various content of zeolite with cement on improving the mechanical and durability of concrete at high temperatures

One of the major environmental contamination factors is cement production and of major damaging factors of reinforced concrete structures is high temperatures. In this study, the effect of substitution of 10 and 20% of cement weight with zeolite on mechanical and durability properties of concrete structures at high temperatures has been investigated. Mechanical properties including compressive and tensile strength of concrete in the hot condition and the durability characteristics of the concrete after cooling, including surface water absorption, the penetration depth of water, electrical resistance and weight loss have been investigated. This study covers temperatures of 28 to 800 ° C. The results showed that the replacement of cement with zeolite reduced the compressive strength and tensile strength of 28 and 42 days. This assessment at high temperatures showed that although the replacement a portion of cement with zeolite decreased the compressive strength of normal concrete, the normalized compressive strength improved at most test temperatures. In addition, it was observed that by substitution 10 and 20% of cement weight with zeolite, the tensile strength of normal concrete at high temperatures increased by 21 and 13 percent averagely. This improvement for normalized tensile strength was 22 and 14%, respectively for mentioned substitution. Although the increase in the test temperature has had adverse effects on the durability of concrete, the replacement of cement with zeolite has improved the durability specification. The best durability properties of concrete were achieved in samples containing higher percentages of zeolite.