Currently, shear transfer models have diverse assumptions about the contribution of shear reinforcements and concrete to the shear capacity of interfaces between concretes cast at different times (that is, cold joints). Furthermore, the knowledge about the effect of high-strength shear reinforcements (HSSR) having a nominal yield strength exceeding 414 MPa (60 ksi), is still limited. This study aims to determine the extent to which shear reinforcements and concrete contribute to the shear capacity of cold joints and explore the effect of HSSR on shear transfer behavior. To this end, nine cold joint push-off specimens were tested to investigate the effects of yield strength of shear reinforcement (YSSR) and concrete compressive strength (CCS) on the interface shear strength and stiffness. In addition, code provisions evaluation was used to identify the degree of concrete contribution, based on a database of 108 cold joint push-off test results established in this study. Test results indicate that the increase of YSSR (rising from 400 MPa to 600 MPa) has no evident effect on the shear strength and stiffness of cold joints, whereas the increase of CCS can significantly increase them. Moreover, when CCS rises from 20 MPa to 50 MPa, the interface shear capacity of push-off specimens increases by approximately 110%, i.e., from 103.5 kN to 217.5 kN. Hence, concrete has a considerable contribution, whereas the contribution of shear reinforcements is not as great as expected. Code provisions evaluation results also indicate that concrete considerably contributes to the shear capacity in the form of cohesion. On the basis of these findings and current design equations, a shear capacity equation, which accounts for the effect of CCS and the limited participation of shear reinforcements, is proposed. This equation is found to provide reasonable prediction of cold joint shear capacity, especially for the cold joint composed of high-strength concrete.

Polymer fiber rubber-reinforced concrete (PFRRC) represents a high-performance composite material that synergistically integrates the energy absorption of rubber concrete (RC) and the crack resistance of polymer fiber-reinforced concrete (PFRC). This review systematically evaluates the mechanical and durability properties of PFRRC, emphasizing its potential to overcome the intrinsic brittleness of conventional concrete while enhancing structural resilience. Experimental results indicate that PFRRC exhibits significant improvements in compressive, tensile, and flexural strength, with increases of up to 29%, 38%, and 66%, respectively, compared to RC. Furthermore, it demonstrates exceptional impact resistance, with energy absorption capabilities up to 10 times greater than that of ordinary concrete. The hybrid composite also demonstrates enhanced durability, including reduced chloride ion penetration (24.5% lower diffusion coefficient) and improved freeze–thaw resistance. However, challenges remain in optimizing rubber–polymer interactions, fiber hybridization ratios, and performance under extreme conditions. By addressing these limitations, PFRRC holds transformative potential for sustainable infrastructure, particularly in road engineering, seismic-resistant structures, and protective systems.

The proper reutilization of the phosphogypsum (PG) by-product derived from the production of phosphoric acid and recycled concrete aggregate (RCA) from waste concrete in roadbase materials is of great necessity and importance. This investigation tried seeking a new approach to reuse them to high quality, including turning PG into calcinated PG (CPG) via washing and calcination, as well as adopting sodium metasilicate nonahydrate (SMN) to strengthen the roadbase materials of cement-stabilized CPG and RCA. Upon the mix design, with a series of experiments including unconfined compressive strength, the wet–dry cycle, freeze–thaw cycle, and scanning electron microscopy, the comprehensive effects of PG treatment, the CPG to RCA mix ratio, SMN dosage, wet–dry cycle and freeze–thaw cycle on the road performance of roadbase materials were well evaluated, and the traffic bearing capacity and microstructure characteristics were also analyzed. The results demonstrate that the 7 d unconfined compressive strength of CPG/RCA roadbase materials can reach 5.34 MPa as the CPG and SMN dosage are 20% and 11%, respectively, which meets the requirements of an extremely and very heavy traffic grade. After five wet–dry cycles and freeze–thaw cycles, the resistance of the CPG/RCA roadbase materials to moisture and frost was significantly improved as 11% SMN was added. Meanwhile, SMN contributes to the reduction in crack width and densifies the microstructure of CPG/RCA roadbase materials. The research results can be used to provide new guidance for building more durable roadbase materials.

In this paper, the failure process of concrete arch dam is the focus of research. Based on the quasi-static solution technique, the explicit analysis method is used to study the failure process of 78m high concrete double-curve arch dam under the condition of homogeneous dam foundation. The whole process of plastic failure of the concrete arch dam with homogeneous foundation in the process of overload from local damage to whole failure is studied. The numerical simulation results show that under the same load case, the calculation results of explicit analysis and implicit analysis are basically the same. The implicit analysis does not converge when the overloaded factor is 1.64, and the explicit analysis method based on the quasi-static solution technique can simulate the failure process of the arch dam more complete. When the overloaded factor reaches 6.0, the plastic failure zone of the dam body is connected, and the arch dam structure fails.

The excessive deflection of large-span cantilever cast prestressed concrete (LCCPC) box girders has always been a complex problem to be solved in bridge engineering. To analyze the effect of shear deformation at segmental joints on the deflection of LCCPC box girders, comparison tests were carried out on three prestressed concrete (PC) I-girders with joints and a PC I-girder without joints, and a finite element simulation method of segmental joints was proposed based on the tests. Subsequently, finite element analysis was conducted on a test girder and the Assistant Shipping Channel Bridge of Humen Bridge (a PC continuous rigid frame bridge with a main span of 270 m) using this method. The experimental and theoretical analysis results showed that the effect of the shear deformation at joints compared to the deformation at midspan of the girder specimens was negligible. Deformation at midspan of the specimens would not significantly increase, even if shear rigidity at the joints was significantly reduced or there were more joints in the girder specimen. The effect of shear deformation at segmental joints on the deflection of LCCPC box girders was quite small and thus insignificant.