This study analyzed the effect of the hardness of coarse aggregates mixed in concrete on the ultrasonic pulse velocity (UPV) and elastic modulus after high temperature exposure. Specimens were classified into normal concrete (NC) mixed with normal aggregates and lightweight aggregate concrete (LC) mixed with lightweight aggregates, and the water-to-binder ratios (W/B) were set to 0.41, 0.33, and 0.28 to determine the characteristics at various strengths. The mass loss, UPV, and elastic modulus were investigated, and the target temperatures were set to 23, 100, 200, 300, 500, and 700 °C. In addition, the correlation between the UPV and elastic modulus was analyzed according to the W/B. After high temperature exposure, the residual mechanical properties for LC improved compared to those for NC, and the LC graph exceeded the NC graph owing to the correlation analysis between the UPV and elastic modulus. Finally, an equation for predicting the elastic modulus based on the UPV after high temperature exposure was proposed.
In this study, combustion tests, in which the opening condition of a fire source was changed using a large-scale compartment and horizontal member, were conducted. The inner temperature, temperature distribution under the horizontal member, external flame shape, and neutral zone height of the compartment were measured under various opening conditions. The results were analyzed using the temperature prediction equation for the opening jet plume at the bottom of a horizontal member, proposed by the Architectural Institute of Japan (Building fire load and design fire property guideline (draft)), and a review was deemed necessary.
In this study, combustion experiments were conducted by changing the fire source conditions and opening conditions for excess fuel gas using a large-scale fire compartment. It was found that the occurrence of external flames depends on the opening factor A √H , surface area of the wall AT, and heat release rate (HRR) QC inside the fire compartment. Moreover, the larger the value of A √H in the experiment, the greater is the temperature rise in the compartment. McCaffrey's proposed temperature prediction model for the upper layer of the fire compartment was also modified and validated.
In this study, a large compartment was used and opening shapes were changed to set fire-source conditions and then combustion tests were conducted to quantitatively measure temperature and heat flux near a façade wall. In addition, <i>q</i> was inferred from the relationship between <i>z</i> and <i>q</i> for the top of the opening under different fire-source conditions and for various opening shapes so that <i>q</i> could be used as a reference index.
This study is an experimental study on behavior of the fire plume ejected from an opening under soffit with H-beam beneath the tip. We used a large-scale experimental apparatus. Also, experimental conditions are the opening size, soffit size, handrail, and fire source. The temperature prediction under the soffit is proposed by using the Watanabe model (predictions of ceiling jet temperature by combining a two-layer zone model) and the Ohmiya model (predictions of the vicinity of vertical wall temperature) in combination. It was confirmed that the calculated value and the experimental result mostly match.
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