In this study, the mechanical properties of the basalt leno textile applied as concrete reinforcement were experimentally investigated considering different parameters including the impregnation materials, geometrical characteristics (the number of yarns, yarn structure, and yarn spacing), and loading rate. The tensile strength, elastic modulus, and failure mode were examined. Furthermore, the force mechanism of impregnated leno textile under tensile load was analyzed. The experimental results showed that the textile with a stiff impregnation material exhibited a higher strength and modulus than that with a flexible material. The leno textile with the straight yarn had a better performance than those with the twisted yarns. Besides, the constraint of the weft yarns is obvious to the textile in the warp direction, while the warp yarn makes no contributions to the bearing capacity of textile in the weft direction. The weft yarn spacing had a significant impact on mechanical properties of the textile in the warp direction. Furthermore, the loading rate of approximately 1.2 mm/min was suggested to determine the maximum force of the impregnated basalt leno textile. A tensile strength model was proposed considering the effects of the impregnation material, consistent deformation, torsion damage, and twisted angle.

The aim of this study is to improve the bond performance of basalt fiber reinforced polymer (BFRP) bars and recycled aggregate concrete (RAC) after being exposed to high temperatures. The bond behavior (failure modes, bond strength, bond stress-slip curves) between BFRP bars and hybrid fiber recycled aggregate concrete (HFRAC) after being exposed to temperatures ranging from 20°C up to 500°C was studied by using pull-out tests. The effect of high temperatures on mechanical properties of concrete (compressive strength, splitting tensile strength) and tensile strength of BFRP bars was also investigated. The bond strength decreased as the temperature increased and the drop of bond strength between RAC and BFRP bar was larger than that between HFRAC and BFRP bar. As the temperature rises, the key factor affecting the bond strength was gradually transformed from concrete strength to BFRP bar strength. The relationship between bond stress and slip in the dimensionless bond stress-slip ascending section was established, which was in good agreement with the experimental results.

In the present study, we investigate the effect of the adiabatic temperature rise property of rock-fill concrete (RFC) on the temperature stress and crack resistance of RFC gravity dams. We conducted tests on the adiabatic temperature rise of RFC with a rock-fill ratio of 42%, 49%, and 55%, respectively. Based on the regression analysis of the test data, a calculation model of the adiabatic temperature rise, considering the rock-fill ratio, is developed, and the finite element analysis software ANSYS is employed to simulate the whole process of the temperature and temperature stress fields of a RFC gravity dam. The main findings of the study are as follows: (1) Both the adiabatic temperature rise rate and the final adiabatic temperature rise of RFC are negatively correlated with the rock-fill ratio. (2) The calculation model of the adiabatic temperature rise of RFC is characterized by its high accuracy, which can help predict the adiabatic temperature rise of RFC with different rock-fill ratios. (3) Without any temperature control measures, the maximum temperature stress of RFC generated by the temperature rise of hydration heat in the RFC gravity dam is 0.93 MPa, which meets the standard of temperature stress control. The results of the present study indicate that dam construction with RFC can simplify the measures of temperature control and crack prevention, improve the construction efficiency, and reduce the cost of dam construction.

As with any concrete dam, temperature stress is a major issue and when it exceeds its maximum limits cracks may occur, the roller compacted concrete (RCC) arch dam is no exception. To overcome this issue, the specific setting of induced joints in the dam can induce cracks at these positions reducing the effect of temperature cracks. However, the study of the induced joints usually ignores the influence of concrete age on the induced joints, thus the obtained equivalent strength of the induced joints deviate from the actual situation. In this paper, the axial tensile test of the both-way interval induced joint test piece of RCC is carried out, in which quantitative analysis is performed on the variation rules of its equivalent strength under different ages and degrees of weakening. The finite element calculation software was also used to perform numerical simulation of the axial tensile test piece, and conduct comparison and analysis between the simulation and test results, thus verifying the correctness and reliability of the equivalent strength model of the both-way interval non-penetrating induced joint established by the test. According to the stress distribution cloud map of the simulated induced joint, the development process of the induced crack under the load was analyzed to propose a more reasonable type of induced joint layout, thus further optimizing the fracture test of the RCC induced joints, and providing a basis for the design of induced joints in actual engineering practice.