Analysis And Research On Evaluation Of The Fire Temperature Imposed On Concrete By The Ignition Loss

Based on a great deal of literatures at home and abroad, the numerical analysis and practical decision method of the fire temperature imposed on concrete construction after fire hazard are generalized systematical in this paper. The numerical calculation mostly establishes complex mathematical models and can only be solved by computer. It is commonly used in theoretical analysis and has less practicability. The experimental method is more intuitionistic, simple and applied in fire investigation. In the past fire investigations, the burnt concrete was regarded as one of the important material evidence. The temporal temperature of the fire spot can be estimate by researching its variation under high temperature. The fire temperature and action time imposed on concrete construction can be analysed by use of fire remains and chemical method, such as the neutral measurement, CO2 and CaO content test. Further more, the research of burnt concrete can help to judge the spot where the fire had stared and so on. For the first time, it is put forward that the application of the ignition loss test in evaluation of the fire temperature imposed on concrete construction in fire investigation in this paper. The ignition loss test was researched to evaluate of the fire temperature imposed on concrete construction. The regression relationship between analysis concrete ignition loss and temperature was established combining the principal of mathematical regression analysis, and using the regression equation the fire temperature was calculated. By the experiment demonstration and comparative analysis, it shows that the concrete ignition loss test is a relatively accurate method to appraise the exposure to fire temperature. On this ground, there is a brief introduction about the application of the concrete ignition loss test to analysis of the concrete member's sectional temperature distribution and estimation of the fire time and fire temperature. Taken core various samples from the exterior to the interior of the concrete member, the fire temperature imposed on concrete in different depths and sectional temperature distribution could be got. The temperature distribution and its variation with time, mainly lies on temperature-time curve and the continue time of the member's surrounding medium (airflow layer). The fire temperature and time can hereby be reckoned. It is significant for judging the fire spread direction, ascertaining the spot on fire, cognizing the fire cause, evaluating and repairing the fire damage in concrete construction. As a relatively accurate method to appraise the exposure to fire temperature, the ignition loss test has the characteristics of simple apparatus and equipment with easy manipulation and practicability. It can calculate the fire temperature imposed on the concrete construction, so it is advised to be used in the fire investigation. The ignition loss test is also affected by some factors. Notices and control measures are described in this paper too, so as to improve the veracity and reliability of the ignition loss test method.