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Uniaxial tensile behaviors of basalt fiber and basalt textile reinforced fine-grained concrete composites under the same fiber volume content with different curing cycles (7 days, 14 days, 21 days and 28 days) were investigated using acoustic emission technology (AE), specifically, including three types of basalt fibers (0.34%, 0.68% and 1.02%) and basalt textiles (1, 2 and 3). The results indicated that the tensile strength of specimens was positively correlated with the curing cycles. As the volume content of basalt fiber increased, the reinforcing effect on fine-grained concrete was improved. The Aveton-Cooper-Kelly (ACK) model was the starting point for analyzing the reinforcement mechanism of basalt textiles. Compared with basalt fibers, basalt textiles could significantly improve the cracking load, ultimate load, cracking displacement and ultimate displacement of fine-grained concrete. The specimens had obvious characteristics of strain hardening during the entire fracture process. The AE signals had a high correlation with the the load-displacement curves during entire experimental process. AE signals were classified to illustrate different fracture mechanisms: textiles slipping, textiles pulling out, matrix-textiles debonding and textiles breaking. AE technology was comprehensively used for the first time to compare and describe the uniaxial tensile properties of basalt fibers and basalt textiles reinforced fine-grained concrete composites. [ABSTRACT FROM AUTHOR]

The tetrahedral structure of the basalt fabric is damaged when it is corroded by hydroxide ions, which greatly limits its application in the field of construction engineering as a result of the concrete matrix present in a strongly alkaline environment (pH >12.5). In this investigation, the alkali-resistant basalt fabric was successfully assembled by structuring mussel-inspired polydopamine (PDA) and zirconia (ZrO2) coatings on fabric surfaces. SEM, SWCA, XRD, FI-IR, RS, and XPS were used to analyze them. The mechanical properties of the different basalt fiber bundles accelerated aging in sodium hydroxide solution were tested. The interfacial behavior between basalt fiber bundles before and after modification and concrete matrix was studied by the acoustic emission (AE) technique. The results illustrated that dense PDA and ZrO2 coatings were dropped onto the surface of the basalt fabric. After being corroded by alkali solution, the final strength retention ratio of modified fabrics was superior to the original basalt fabric. Load–displacement curves of interfacial behavior could be well correlated with AE data in different loading stages of damage initiation, evolution and propagation. A five-stage linear local bond-slip model was proposed to describe the interfacial process between a basalt fiber bundle and concrete. [ABSTRACT FROM AUTHOR]

In this study, the chopped basalt fiber (CBF) with different content and basalt fiber grilles (BFG) with different layers were composed with concrete matrix, respectively. The compressive, splitting tensile and flexural properties of concrete composites were studied by universal material testing machine. The cracks evolution law of specimens was analyzed to reveal the reinforcement mechanism of CBF and BFG. Results showed that under the same fiber volume ratio, BFG were better than CBF to reinforce mechanical properties of concrete. The three kinds of mechanical properties of BFG reinforced concrete were improved highest by 41.46%, 28.26% and 46.13%, respectively. BFG can play a crucial role in stress transmission, bearing load and absorbing energy during the loading process of the specimens. Based on the equivalent stress rectangle theory, an analytic model to predict the ultimate flexural capacity of BFG reinforced concrete was proposed. The experimental results from the flexural test were compared with the predicted values, and a good accuracy of the analytic model was obtained. [ABSTRACT FROM AUTHOR]

The poor alkali resistance of basalt fabric greatly affects the mechanical properties of textile reinforced concrete. In this study, dense zirconia coating obtained by sol-gel method was coated on the basalt fabrics surface as additional sizing to improve the alkali resistance of basalt fabrics. The morphology, wettability and phase composition of the fabric surfaces was characterized by scanning electron microscopy (SEM), static water contact angle (SWCA), X-ray powder diffraction (XRD), fourier transform infrared spectra (FI-IR), X-ray photoelectron spectroscopy (XPS) and Raman. The tensile properties of various basalt fabrics immersed in alkaline solution for different time and the mechanical property of concrete composites were examined by universal material testing machine. Results showed that a protective membrane was formed on the surface of basalt fabrics to prevent the diffusion of hydroxide ions. The final strength retention ratio of BF-c-ZrO2 (Basalt fabric-coated-Zirconia) fabrics could maintain at 89.92% compared with that of pristine basalt fabrics, which reached below 40%. The compressive strength and flexural strength of BF-c-ZrO2 fabrics reinforced concrete increased by 10.15% and 19.0% compared with that of pristine basalt fabrics reinforced concrete. A theoretical model was proposed to predict the ultimate flexural bearing capacity of BF-c-ZrO2 fabric reinforced concrete based on the equivalent stress rectangle theory. The corresponding predicted value compared with experimental result indicated a good coincidence and a reasonable accuracy, which was less than 5% of their discrepancy. [ABSTRACT FROM AUTHOR]

The research work is conducted to investigate the influence on the dynamic mechanical properties of concrete with different volume content of basalt fibers and the different layers number of basalt fabrics, as well as the hybrid effect between fibers and fabrics. The relationships among the impact force, impact time, displacement of the specimens and their failure patterns were analyzed. The results showed that the basalt fabric could significantly improve the brittleness and the impact resistance of concrete. Moreover, the impact force and energy absorption of the specimens increased continuously with the increase of impact energy. The fabrics could play the vital roles in transmitting stress, absorbing energy and bearing load. Basalt fiber could enhance the impact resistance of concrete but it was not obvious. Finally, the different reinforcement mechanisms of basalt fiber and basalt fabric under impact load were proposed. [ABSTRACT FROM AUTHOR]

Paper machine white water is generally characterized as a high concentration of suspended solids and organic matters. A combined physicochemical–biological and filtration process was used in the study for removing pollutants in the wastewater. The removal efficiency of the pollutant in physicochemical and biological process was evaluated, respectively. Furthermore, advanced technology was used to analyse the water quality before and after the process treatment. Experimental results showed that the removal efficiency of suspend solids (SS) of the system was above 99%, while the physicochemical treatment in the forepart of the system had achieved about 97%. The removal efficiency of chemical oxygen demand (COD) and colour had the similar trend after physicochemical treatment and were corresponding to the proportion of suspended and the near-colloidal organic matter in the wastewater. After biological treatment, the removal efficiency of COD and colour achieved were about 97% and 90%, respectively. Furthermore, molecular weight (MW) distribution analysis showed that after treatment low MW molecules (<5 kDa) increased. Three-dimensional excitation-emission matrix fluorescence analysis showed that most humic-like substances were effectively removed during the treatment. The analyses of gas chromatography/mass spectrometry showed that the composition of organic matter in the wastewater was not complicated. Methylsiloxanes were the typical organic components in the raw wastewater and most of them were removed after treatment. [ABSTRACT FROM AUTHOR]