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Flexural performance of hybrid fiber reinforced cement-based materials incorporating ceramic wastes

Wu Lipeng, Li Xuanhao, Deng Hai

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

491--506

EN

Ceramic waste generated by demolition and manufacturing processes is a kind of widely discharged solid waste; its sustainable use can reduce resource extraction, energy consumption, and carbon emissions, thereby reducing the environmental impact. In this study, ceramic powder and ceramic sand were prepared using waste ceramic wall tiles. By using three water-to-binder ratios of 0.30, 0.32, and 0.34, five ceramic powder replacement rates of 10% to 50%, and completely using ceramic sand as the fine aggregate, specimens with large differences in mechanical properties were prepared. Firstly, the compressive strength was investigated. On this basis, hybrid fibers were employed to strengthen the new matrix material, and its bending resistance was experimentally studied. It was found that the incorporation of ceramic powder reduced the compressive strength of the matrix. The water-binder ratio significantly affects compressive strength at an early age. The effect of PVA fiber on improving the ductility of the new composite is distinct. Increasing the amount of steel fiber can effectively enhance the bending bearing capacity. With a ceramic powder dosage of 50%, the new composite has shown ductile failure characteristics, even with low total fiber content. The bending properties of this new composite material, which makes extensive use of ceramic waste, are well adjustable. The bearing capacity and ductility balance can be achieved with the steel fiber content of 1% and the PVA fiber content of 1.2% to 1.50%.

2

Flexural cracking behavior and calculation approach of reinforced highly ductile fiber-reinforced concrete beams

Zhang Min, Deng Mingke, Wu Zhiyan, Pan Jiaojiao

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

320--333

EN

Highly ductile fiber-reinforced concrete (HDC) is a class of cementitious composites reinforced with polyvinyl alcohol (PVA) fibers and exhibits strain-hardening behavior and multiple fine cracks under tension. This study aims to evaluate the cracking behavior and propose a simple calculation approach of the crack width and crack spacing of reinforced HDC (RHDC) flexural members. The four-point bending tests were conducted for RHDC beams with a different ultimate tensile strain of HDC and tensile reinforcement ratio. The flexural cracking performance of beams was mainly analyzed. The results showed that the width, spacing, height of flexural cracks of RHDC beams was significantly smaller compared with those of reinforced concrete (RC) beams. An increase in the ultimate tensile strain of HDC decreases the crack width and crack height while has little influence on the average crack spacing of RHDC beams. The effect of the tensile reinforcement ratio on the crack width is notable for RHDC beams with a higher ultimate tensile strain of HDC. The increasing of the tensile reinforcement ratio decreases the average crack spacing and crack height of RHDC beams. Furthermore, theoretical formulas for the average crack spacing, average crack width, and maximum crack width of RHDC beams were proposed based on the bond interaction between rebars and HDC and the fiber bridging stress. The predicted values have good agreement with the experimental values, indicating that the proposed method is reliable to evaluate the crack behavior of RHDC flexural members. Based on an accurate validation, the effect of cover thickness, HDC strength, and rebar diameter on the crack behavior of RHDC beams was conducted and found consistent with the law of RC beams.

3

Flexural performance of engineered cementitious compositelayered reinforced concrete beams

Krishnaraja A. R., Kandasamy Dr. S.

Archives of Civil Engineering

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2017

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Vol. 63, nr 4

173--189

EN

This study focuses to develop a new hybrid Engineered Cementitious Composite (ECC) and assesses the performance of a new hybrid ECC based on the steel short random fiber reinforcement. This hybrid ECC aims to improve the tensile strength of cementitious material and enhance better flexural performance in an RC beam. In this study, four different mixes have been investigated. ECC with Poly Vinyl Alcohol (PVA) fiber and PolyPropylene (PP) fiber of 2.0% volume fraction are the two Mono fiber mixes; ECC mix with PVA fiber of 0.65% volume fraction hybridized with steel fiber of 1.35% volume fraction, PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction are the two additional different hybrid mixes. The material properties of mono fiber ECC with 2.0 % of PVA is kept as the reference mix in this study. The hybridization with fibers has a notable achievement on the uniaxial tensile strength, compressive strength, Young’s modulus, and flexural behavior in ECC layered RC beams. From the results, it has been observed that the mix with PVA fiber of 0.65% volume fraction hybrid with steel fiber of 1.35% volume fraction exhibitimprovements in tensile strength, flexural strength, andenergy absorption. ThePP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction mix has reasonable flexural performance and notable achievement in displacement ductility overthe reference mix.

PL

Zaprojektowany kompozyt cementowy (ECC) jest materiałem przygotowywanym na bazie zaprawy cementowej z wykorzystaniem krótkiego włókna, z udziałem objętościowym do 2,0%. Należy do rodziny Kompozytu Cementowego o Bardzo Wysokiej Wytrzymałości (UHTCC), który wykazuje wyjątkowe właściwości mechaniczne w zakresie umocnienia odkształceniowego, wytrzymałości na rozciąganie i odporności na odkształcenia. Typ, geometria, udział objętościowy i inne właściwości wytrzymałościowe włókien stosowanych w mieszance decydują o mechanicznych zachowaniach ECC. Mieszanki ECC są zwykle opracowywane z wykorzystaniem włókna polialkoholu winylowego (PVA), włókna stalowego (SE), włókna polipropylenowego (PP) i włókna polietylenowego (PE). Celem zastosowania włókien jest poprawa umocnienia odkształceniowego, wytrzymałości na rozciąganie i pochłaniania energii betonu, co zmniejsza uszkodzenia w konstrukcji betonowej poddanej wpływom dynamicznym i uderzeniowym. W celu zbadania zachowania ECC podczas testu ściskania, wykonano test modułu Younga, bezpośrednią próbę rozciągania oraz test zginania na belkach dla 4 różnych mieszanek. Mieszanka 1 (M1) zawiera 2% włókna PVA, mieszanka 2 (M2) zawiera 2% włókna PP, mieszanka 3 (M3) zawiera 0,65% PVA i 1,35% włókien stalowych, mieszanka 4 (M4) zawiera 0,65% PP i 1,35% włókien stalowych.