A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Ordinary Portland Cement (OPC) is a widely used construction material. In airbase facilities, it is used to construct the runways and parking aprons. During the takeoff and landing of aircrafts, the high temperature exhaust has splashed to the concrete pavement from the modem vectored thrust engines (VTE) or auxiliary Power Unit (APU). The APU is a low-power has turbine that provides compressed air, from a load driven compressor, for starting the main engines and for operating auxiliary systems during ground maintenance. In particular, the exhaust gas temperature of a VTE could rapidly reach over 700 deg C, and the corresponding exhaust velocities could go beyond 1800 ft/s. The pavement is subjected to extremely rapid transient high temperature loadings as well as thermal cycles of heating and cooling. Figure 1.1 shows a typical damaged area in an F/A-18 parking apron. The origin of the problem is the F/A-18 auxiliary power unit, which is located at the bottom of the fuselage near the tail section. The exhaust gas temperature isotherms on the pavement top are almost circular and show a decrease along the radios. Chemical degradation of concrete due to hydraulic fluid, lubricating oils also contribute to the damage of concrete pavement. The U.S. Department of Defense has seen an increase in airfield concrete apron distress in the form of surface scaling when the aprons are exposed to cyclic heat, spilled lubricants, and/or hydraulic fluid (McVay, Smithson and Manzione, 1993). Chemical analysis of the damaged concrete reveals that the spilled fluid from the engines are undergoing hydrolysis (breakdown) accompanied by the consumption of calcium hydroxide, plus hydrated silicate and aluminate phases.
Ordinary Portland Cement (OPC) is a widely used construction material. In airbase facilities, it is used to construct the runways and parking aprons. During the takeoff and landing of aircrafts, the high temperature exhaust has splashed to the concrete pavement from the modem vectored thrust engines (VTE) or auxiliary Power Unit (APU). The APU is a low-power has turbine that provides compressed air, from a load driven compressor, for starting the main engines and for operating auxiliary systems during ground maintenance. In particular, the exhaust gas temperature of a VTE could rapidly reach over 700 deg C, and the corresponding exhaust velocities could go beyond 1800 ft/s. The pavement is subjected to extremely rapid transient high temperature loadings as well as thermal cycles of heating and cooling. Figure 1.1 shows a typical damaged area in an F/A-18 parking apron. The origin of the problem is the F/A-18 auxiliary power unit, which is located at the bottom of the fuselage near the tail section. The exhaust gas temperature isotherms on the pavement top are almost circular and show a decrease along the radios. Chemical degradation of concrete due to hydraulic fluid, lubricating oils also contribute to the damage of concrete pavement. The U.S. Department of Defense has seen an increase in airfield concrete apron distress in the form of surface scaling when the aprons are exposed to cyclic heat, spilled lubricants, and/or hydraulic fluid (McVay, Smithson and Manzione, 1993). Chemical analysis of the damaged concrete reveals that the spilled fluid from the engines are undergoing hydrolysis (breakdown) accompanied by the consumption of calcium hydroxide, plus hydrated silicate and aluminate phases.
Thermo-Micromechanical Damage Models of Airfield Concrete Pavement Under High Temperature Loading
1998
15 pages
Report
No indication
English
Construction Equipment, Materials, & Supplies , Aeronautics , Analytical Chemistry , Pavements , Landing fields , Runways , Chemical analysis , Parking facilities , Temperature , Department of defense , Military facilities , Tail assemblies , High temperature , Cements , Heating , Scaling factor , Fuselages , Takeoff , Power equipment , Radio equipment , Turbines , Calcium compounds , Ground support , Thrusters , Thrust vector control systems , Isotherms , Compressed air , Construction materials , Chemical attack(Degradation) , Hydraulic fluids , Lubricating oils , Aluminates , Exhaust gases , Vte(Vectored thrust engines) , Apu(Auxillary power unit) , F/a-18 aircraft
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