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Ductility deficiency in reinforced concrete (RC) piers is a substantial factor contributing to earthquake damage in bridge structures. In this study, the conventional concrete in the potential plastic hinge area was substituted with polypropylene fiber-reinforced engineered cementitious composite (PP-ECC), thereby leveraging its high ductility characteristics to explore the seismic performance of RC piers strengthened by PP-ECC. A finite element model was established to discuss the reinforced height, axial compression ratio, longitudinal reinforcement ratio and stirrup ratio on the hysteresis performance by referring to a published paper with a 1/5 scale test specimen. Based on the results of the parameter analysis, an ideal set of configuration parameters was proposed. Subsequently, a full-size simplified mechanical model was established with ideal reinforcement parameters. Time-history and pushover analysis were utilized to test the seismic response. The study indicates that the two analytical methods were largely consistent. The improvement in the displacement and shear force of the strengthened pier gradually decreased with the increase in acceleration amplitude. Time-history analysis reveals a decrease in the enhancement of displacement from 82.26% to 17.98% and a reduction at the bottom reaction from 12.2% to 1.5%. Under the pushover analysis method, the retrofitting level of the top displacement decreased from 77.22% to 11.53%, whereas the improvement level of the bottom shear decreased from 9.62% to 3.69%. These results provide a theoretical basis and reference standard for the application of PP-ECC. [ABSTRACT FROM AUTHOR]

As large-scale infrastructure construction projects conclude, the overall civil construction market shrinks, leading to increased competition among construction companies. Accordingly, various construction companies are gradually emphasizing the issue of project costs. Numerous studies have shown the impact of material costs on the overall project cost. However, sharp fluctuations in material prices have been observed in recent years due to various unstable factors in the market. Thus, accurate prediction of material prices facilitates the development of appropriate material procurement strategies to deal with market risks. This paper collects the rebar prices announced in the first half of 2023 in China's Guangdong Province, selects one type of rebar price as a representative, and analyzes the time series characteristics of the rebar price composition. Then, it judges whether the time series passes the white noise detection, grey correlation detection, and level ratio detection. The prediction model is established based on the seasonal auto-regressive integrated moving average (SARIMA) model and the grey model (GM) (1.1) to predict future rebar prices. According to the characteristics of the rebar price data in June 2023, the residual inverse method combines the results predicted by the two models. The price in the early and middle of July 2023 is then predicted using the newly constructed combined model. The results indicate that the combined model is more accurate than the single prediction model. [ABSTRACT FROM AUTHOR]

The present study investigates the influences of SiC incorporation on the microstructure and corrosion behavior of B4C–nSiC composites in molten FLiNaK salt at 800°C. The corrosion characteristics and mechanisms of B4C–nSiC composites in molten FLiNaK salt were thoroughly characterized and extensively discussed. The B4C–nSiC composites exhibited a more refined grain size and lowered apparent porosity as the SiC content increased. Additionally, the concentration of high‐angle grain boundaries (HAGBs) in B4C–nSiC composites increased as the SiC content increased. The incorporation of 10 wt.% SiC improved the corrosion resistance of B4C–nSiC composites against molten FLiNaK salt. However, the incorporation of excessive SiC (≥20 wt.%) did not improve the corrosion resistance. The best corrosion resistance of B4C–10% SiC ceramic composite was attributed, on the one hand, to its relatively low apparent porosity and the low concentration of HAGBs with high structural disorder. On the other hand, the selective corrosion of B4C in B4C–10% SiC ceramic composite rapidly formed a sufficiently thick and highly graphitized C‐rich layer on its surface during the initial stages of the corrosion test. The C‐rich layer maintained the integral structure of the ceramic and prevented subsequent corrosive medium from penetrating into the ceramic. [ABSTRACT FROM AUTHOR]

A preliminary experimental investigation of box-section reinforced concrete (RC) beams strengthened with carbon-fibre-reinforced polymer (CFRP) under shear and torsion was carried out. Based on different torque-to-shear ratios (TSRs) (0.958, 1.597, and 2.556), 12 box-section specimens were divided into three groups. In each group, one beam was a non-strengthened control while the other three beams were strengthened with CFRP U-jackets or CFRP U-jackets and longitudinal strips. Tests on the beams showed that the average cracking angle at the ultimate state was inversely proportional to the TSR. Two failure patterns were observed: debonding in the beams strengthened with U-jackets and fracture in the beams strengthened with both U-jackets with longitudinal strips. At the ultimate state, the best improvement in torsional capacity was achieved in the specimens retrofitted with longitudinal strips bonded on the U-wrapping strips. Equations using a modified effective strain expression were developed to compute the ultimate torque of all the specimens, the results of which were in good agreement to existing experimental data. [ABSTRACT FROM AUTHOR]