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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

Feasible brittleness evaluation method and suggestion for brittleness reduction of cementitious materials based on stress–strain curve

Fu Qiang, Wang Zhenhua, Zhou Zhiming, Niu Ditao, Wang Yan

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e209, 2022

EN

In this study, a brittleness evaluation index B5 and brittleness–plasticity classification standard for cementitious materials were established, and a suggestion for brittleness reduction was proposed. The results showed that B5 established based on the principle of energy conversion can effectively characterize the variation in the brittleness of cementitious materials with the confining pressure, and the brittleness order of different cementitious materials. Based on the established brittleness–plasticity classification standard, the ranges of B5 corresponding to the weak, high and ideal brittleness are [0.3, 0.6), [0.6, 1) and 1, respectively; and those corresponding to the weak, high and ideal plasticity are [0.1, 0.3), (0, 0.1) and 0, respectively. Finally, a suggestion for brittleness reduction using prismatic aggregates and hybrid nanofibers, flexible and rigid fibers of different sizes was proposed, and the corresponding design process of cementitious materials with weak brittleness was given. The research results in this study provide a basis for the brittleness evaluation of cementitious materials and the design of cementitious materials with weak brittleness.

3

Experimental investigation of cementitious materials using the prism technique

Messaoudi Rahma, Bouzerira Cherif, Grimes Morad, Oucief Hocine

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 1

196--212

EN

Numerous studies have shown that the non-destructive testing has proved the exceptional role in supervising the quality of concrete. Today, they represent an alternative that contributes to the resolution of materials diagnostic problems without altering them. This work presents an experimental study using a pulse-echo method that has the advantage of generating two types of wave (compressional and shear) by a mode conversion using just one transducer. The samples were made in a prismatic form. The results recovered from backscattered echoes are extracted using an estimation algorithm. These data were exploited to determine velocities of the tested material then the reflection coefficients for related them with the compressive strength. The tests were conducted with six samples with varied water/cement ratio. The results obtained showed that the prism technique has the potential to evaluate characteristics cementitious material using this proposed process.

4

Cauchy-based modelling in cementitious materials technology

Stroeven P., Słowik M.

Archives of Civil Engineering

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2020

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Vol. 66, nr 2

179--190

EN

Cauchy paved the way for constructing models in concrete technology, and elsewhere. He determined the (nonflat) surface area in 3D by measuring random total projections. Analogously, he determined the length of a curved line in 2D by way of measuring the total projections. The paper will present the mathematical expressions, because in many branches of concrete technology, modelling is found based on such Cauchy concepts. These branches – fractography in compression, tension or shear, fibre reinforcement and permeability estimation – will briefly be mentioned to demonstrate this. It has been found that, for the discussed fields of engineering relevance, major model parameters for cementitious materials are similar to those developed by Cauchy in the 19th century. In the paper some previous investigations concerning fractography, fibre reinforcement and fracture roughness will be summarized but basically a new development on porosimetry will be presented. Particularly a new achievement of successful implementation of the methodology (also based on Cauchy) for optimizing permeability estimation will be discussed.

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Ekologiczne materiały cementowe o podwyższonej odporności na działanie środowisk korozyjnych

Błaszczyński T., Król M.

Przegląd Budowlany

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2017

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R. 88, nr 10

56--59

PL

W pracy omówiono zagadnienie ekologiczności cementów. Przedstawiono dwa główne czynniki wpływające na fakt, czy dane spoiwo może być uznane za ekologiczne. Na podstawie badań trwałościowych związanych z odpornością korozyjną zapraw na bazie spoiw cementowych oraz geopolimerowych przedstawiono zalety i wady danych rozwiązań. W porównaniu zestawiono trzy rodzaje materiałów. Były to zaprawy na bazie dwóch cementów: CEM I oraz CEM IV a także wysoko wyspecjalizowanych zapraw na bazie modyfikowanego spoiwa cementowego oraz spoiwa geopolimerowego.