Behavior of Reinforced Modified Reactive Powder Concrete Knee Joints

الملخص

This investigation presents an experimental study of strength and behavior of Modified Reactive Powder Concrete (MRPC) corner subjected to bending moment tended to open the angle. Twelve specimens are tested to study the corner strength, cracks types, cracking moment, cracks patterns, corner deflection, ductility and corner efficiency. Ten MRPC knee joints were mixture of steel fiber, superplasticized, silica fume-cement blended with very low water/cement ratio (w/c) characterized by very fine sand (maximum size 600µm), where the presence of natural crushed aggregate of maximum size (4.75mm) was used to replace a part of the fine sand. The rest two corners of Normal Strength Concrete (NSC) which are the mixture of (1:1.5:3) (cement : sand 4.75mm : gravel 10mm). The specimens are designed to represent an actual prototype of a portal frame corner. The compressive strength of concrete in the test varies from (23.5) to (88.9) MPa, and steel tension ratio in legs is constant, ρ = 0.008, for ten specimens where the two MRPC corners are plain concrete. The specimens are designed to represent an actual prototype of a portal frame corner. The nominal dimensions of the tested corners are (1078 mm) in overall length, (600 mm) in height, the cross section of the corner is rectangular (212×150mm). All corners are supported to be hinged in one leg by two clamps and rolled in other leg, also all corners are loaded by steel frame where,......