Abstract
Nondestructive tests (NDT) are considered one of the methods of evaluation and quality control of concrete. In addition, Nondestructive testing give, good indications about strength and durability of concrete samples and structural members. There are many studies about Nondestructive tests for concrete NSC &HSC. So the fundamental aim of study is to construct a mathematical model to predict compressive strength of two types of concrete (Normal concrete and self compacting concrete ) exposed to high temperatures from Nondestructive testing ,by using (rebound number &ultrasonic pulse velocity). Where mathematical models proposed for concrete normal conditions with previous studies, do not give a true picture of the nature of concrete exposed to high temperature. The study included the preparation of three mathematical models for each type of concrete, two of which are based method of Multiple Linear Regression Analysis with a different number of independent variables supported model, while the third, it depends on the construct of a model of Non - Linear Regression Analysis using the exponentional equation .
The statistical models for normal concrete was high reliability, and owns two of them on two variables only were to hammer Schmidt test , ultrasonic pulse velocity test , and be more practical than the third model, which depends on several variables, where he finds it difficult in most cases Empirical lack of information application . The same result was reached to models for self compacting concrete with a different rate of reliability for both types of concrete for statistical indicators of each model.
