Mechanical Properties of Concrete depending on Cooling Conditions After High Temperature Heating

Abstract

Since the 1960's, various studies have been carried out on the internal and external factors that might affect heated concrete in terms of compressive strength, elastic modulus and thermal stress. In particular, thermal properties of aggregate and cooling methods are known to have a significant influence on concrete residual mechanical properties. This study aims to assess concrete mechanical properties based on the types of aggregate and cooling methods used. The used coarse aggregate in concrete was granite, ash-clay and clay type. The circular concrete specimens of Ø100×200mm used in the experiment were heated to the target temperature to test the mechanical properties at a high temperature, slow cooling (room temperature) and water cooling (quenching) conditions. In conclusion, the research finding reveals that the smaller the thermal expansion of the aggregate, the higher the strain at a high temperature while the more deteriorated the mechanical characters. In addition, the lightweight aggregate concrete was greatly affected by the cooling velocity although the thermal expansion strain of aggregates as the thermal expansion of aggregates took place to a smaller extent, the strength at high temperature remained, while the mechanical properties deteriorated with cooling accelerated. In addition, light-weight aggregate concrete which ash-clay and clay aggregates is greatly affected by the cooling velocity depending on aggregate although the thermal expansion strain of the aggregates was shown to be within a similar range.

Properties of self‐compacting concrete containing copper slag aggregate after heating up to 400°C

“…It has been reported that 500°C is a critical temperature for self‐compacting concrete exposed to fire and the loss of compressive strength is not critical under this temperature . In the previous papers, the possible reason of such increase of the residual compressive strength with the increase of the heating temperature is explained as re‐hydration due to the steam curing in concrete . Since self‐compacting concrete contains more amount of binders, the re‐hydration effect could become significant.…”

Spalling Resistance of Fiber-Reinforced Ultra-High-Strength Concrete Subjected to the ISO-834 Standard Fire Curve: Effects of Thermal Strain and Water Vapor Pressure

“…Within our experimental setup, an electric furnace was installed in a 2000 kN class universal testing machine (UTM, SHIMADZU, Kyoto, Japan) using a steel frame. The temperature was adjusted by applying heat to replicate the conditions of the ISO-834 standard fire curve through preliminary experiments and literature results [ 34 , 35 , 36 , 37 ]. Adjustments were implemented by modulating the electric heater temperature based on measurement of the specimen temperature using a thermocouple (Ø1.6 × 3000 mm sheath + 0.65 mm 2 × 1000 mm thermo shield wire, Jooshin, Incheon, Korea).…”

Influence of Cooling Methods on the Residual Mechanical Behavior of Fire-Exposed Concrete: An Experimental Study

“…Karakoç [32] evaluated the compressive strength of light aggregate concretes and demonstrate that it is influenced by the cooling methods. Kim et al [33] concluded that the cooling rate affects the dimensional variation of the aggregates and that the mechanical properties are deteriorated by accelerated cooling. Xiang et al [34] realized that, for slow cooling, the heating temperature influences the residual cracking pattern and failure mode during compression testing.…”