Fatigue properties of special kind of reinforced concrete composite beams

Abstract

The special reinforced concrete composite beam consists of a steel fiber reinforced self-stressing concrete composite layer and a reinforced concrete T-beam, and constructional bars are set up at their bonding interface. Fatigue properties of the composite beam under the action of negative moment were experimentally studied. Through inverted loading mode the load-bearing state of a composite beam was simulated under the action of negative moment. With the ratios of constructional bars being 0, 0.082% and 0.164% respectively as parameters, the effects of constructional bars on the properties of composite beam, such as fatigue life, crack propagation, rigidity loss as well as damage behavior of bonding interface, were studied. The mechanism of the constructional bars on the fatigue properties of the composite beams and the restriction mechanism of crack widths and rigidity loss were analyzed. The test results show that the constructional bars can enhance the shear resistance of the bonding interface between composite layer and old concrete beam and restrict expanding of steel fiber reinforced self-stressing concrete, which are beneficial to synergistic action of composite layer and old concrete beam, to reducing the stress amplitude of bars and the crack width of composite layer, and to increasing the durability and fatigue life of the composite beam.

Experimental Research on Fatigue Behavior of Reinforced UHPC-NC Composite Beams under Cyclic Loading

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Progress of Surface Modification of Aluminum Pigments

“…Liu Y et al [14]used 3-methacryloxypropyl trimethoxysilane and TEOS, vinyl trimethoxy silane and TEOS, γ-glycidoxypropyl trimethoxysilane ether and TEOS to prepared organic-inorganic hybrid coated aluminum pigments respectively. Huang Shuli [15] used tetrabutyl titanate as precursor to form a dense TiO 2 layer on SiO 2 /A1 particles by sol-gel method. The best encapsulation can be acquired when the volume ratio between TEOS and TBT was 3:5.…”

Synthesis,Characterization and Flocculability of a Poly (p-Ethylstyrene -Acrylamide- Propenohydroxamic Acid)

“…This type of flocculant can provide tight settling interfaces and excellent supernatant clarity, but sometimes settling rates can not meet the demands. Research of hydroxamic acid polymers and theirs copolymers is one of the most popular hot aspects.Different kinds of derivates of hydroxamic acid polymers have been prepared in order to improved flocculation performances [3][4][5][6][7][8][9][10][11][12]. These polymers include hydrophobically associating polyacrylate [13,14], vinyl trimethyloxysilane (VTMS) modified PDADMAC [15], hydrophobically modified chitosan [16], etc.…”