owadays, the use of concrete in small and large structures due to its properties has become more and more popular. According to the use of concrete in a variety of structures, including those exposed to elevated temperature, it is important to improve the physical and chemical properties of concrete. Under high temperature, concrete undergoes physical and chemical changes, which reduces its compressive, tensile, flexural strength and modulus of elasticity and can ultimately damage the structure. Concrete deterioration continues for days and weeks after cooling, causing the concrete to deteriorate more. As a result, using refractory materials in concrete can increase the heat resistance of concrete. Various studies have been carried out on the properties of concrete under high temperature. In many of these researches, ceramics have been used as aggregates in concrete to increase its heat resistance because calcareous aggregates generally decompose by heat and lose their strength. Ceramic not only has a high strength, but also high resistance to heat. The use of refractory cement as a replacement for Portland cement also increases the heat resistance of concrete because the concrete made with ordinary Portland cement loses its strength at temperatures above 600 ° C. The use of polypropylene and steel fibers in concrete prevents the phenomenon of concrete spalling and increases compressive, tensile and flexural strength under high temperature. In this research, waste porcelain ceramic was used as aggregate in concrete. The use of ceramic waste in concrete not only prevents environmental pollution and reuse of this material, but also improves the concrete properties. In this study, two types of polypropylene and steel fibers as well as hybrid fibers, a mixture of these two types, and two types of ordinary Portland cement and refractory cement was used. In this study, air-entrained concrete has also been used as an option to increase heat resistance of concrete. For this purpose, 220 specimens were made with 18 mixing designs. At first, Specimens made with porcelain ceramic aggregates were placed in the furnace at temperatures of 400 and 800 ° C. After cooling, compressive strength, tensile strength, weight loss and cracking assessment using fractal dimension were measured. Then, to investigate the degradation and deterioration of concrete after cooling, the mixtures that had the highest compressive and tensile strength were made with ceramic aggregate and alumina silicate aggregate and placed in the furnace at 1000 ° C and their appearance changes, cracking and deterioration were examined for 4 weeks. The results showed that all samples' compressive and tensile strength decreased with increasing temperature, but their rate of decline was variable. At 400 ° C, samples containing Portland cement, and at 800 ° C, samples containing refractory cement showed higher strength. Application of steel fibers increased the resistance of the specimens to heat and also reduced cracking. The use of polypropylene fibers and air-entrained concrete also prevented spalling phenomenon. Key words: Concrete, high temperature, heat-resistance of concrete, porcelain ceramic aggregate, polypropylene fibers, steel fibers, air-entrained concrete.