Comparing the Impact Strength of Alkali Activated Concrete and Normal Concrete Under High Heat Based on XRD and SEM Tests

In recent decades, structures have been of special importance in terms of defense against natural and man-made disasters. Therefore, the need to build structures with high strength has been one of the concerns of engineers in this field. Concrete as one of the main materials used in concrete structures, has an effective role in improving and enhancing the strength of structures. Concrete resistance to falling weight is known as one of the mechanical properties of concrete. In this laboratory research, a mixing design was made of ordinary concrete with a cement grade of 450 kg / m3. 500 degrees Celsius, compared and evaluated at 90 days of processing age. Next, X-ray diffraction (XRD) spectroscopy and scanning electron microscopy (SEM) tests were performed to further evaluate and validate the impact resistance test results at 90 days of processing time at ambient temperature and 500 ° C. Samples were taken. In the results section, the amount of energy absorbed in the impact test of weight drop at ambient temperature was 244.24 joules for ordinary concrete and 223.89 joules for quilted concrete, which were subjected to high heat application in concrete. They showed a decrease of 90.9% and 72.72%, respectively. The flexibility index in this test under ambient temperature was 2.33 joules for ordinary concrete and 1.58 joules for reinforced concrete, which under high heat in concrete, improved by 28.75%, respectively. They showed a drop of 9.49%. The results of XRD and SEM tests were in coordination with each other and overlapped with the results of impact resistance test.