Rubberized concrete is an environmentally friendly building material that mixes rubber particles from old automobile tires into normal concrete in place of fine aggregate. The addition of rubber particles can improve the abrasion resistance of normal concrete observably. It has a good application prospect in hydraulic engineering, especially in the concrete building parts with high abrasion resistance. However, there are few experimental studies on the abrasion resistance of rubberized concrete, and the influence law and mechanism of rubber particles on the abrasion resistance of concrete are not understood. In this paper, the abrasion resistance of rubberized concrete is studied using the underwater-steel-ball method. The results show that rubber particles increase the slump of concrete mixtures. The abrasion resistance of rubberized concrete increases significantly with increasing rubber particle content, whereas the compressive strength decreases linearly. For the same rubber particle size and content, the abrasion resistance of rubberized concrete positively correlates with compressive strength and larger rubber particles significantly improve the abrasion resistance. Rubber particle content is the factor that most strongly affects abrasion resistance of rubberized concrete, followed by the compressive strength. Rubber particle pretreatment methods of NaOH + KH570 can significantly improve the abrasion resistance of rubberized concrete.

Scholars have studied the impact of rubber particles (RPs) on the performance of the concrete and the research topics have covered all the mechanical properties and durability of normal concrete (NC). Recently, scholars have turned their research interest to the structural properties of concrete. However, there are few experimental studies on the bonding properties of RC to NC. The RPs have both positive and negative impacts on the bond performance. On one hand, RPs can reduce the shrinkage of concrete, resulting in reduced shear stress and tensile stress near the bonding boundary. On the other hand, RPs cause a reduction in the overall strength of concrete, resulting in the poor mechanical performance of the interface transition layer between the two concrete. The test results of this study show that the bonding splitting tensile strength between freshly mixed RC to aged NC first increases and then decreases with the rise of the RPs content in the RC, and the bonding splitting tensile strength reaches the peak when the RPs content is 10%. The bonding splitting tensile strength between the NC and the RC mixed with 3–5 mm RP is higher than that between the NC and the RC mixed with 1–3 mm RPs. When mixed with modified RPs, the bonding splitting tensile strength between the RC and the NC is improved. Applying an interfacial agent (a cement slurry or an epoxy) on the old concrete bonding surface can significantly improve the bonding splitting tensile strength. The results of non-repeated two-way ANOVA show that the content of the RPs and the type of the interfacial agent have significant effects on the bond splitting tensile strength, while the size and modification of the RPs have no significant effects on the bond splitting tensile strength.

To overcome the shortcomings of traditional concrete coatings, such as high roughness and poor frost resistance, this study developed and evaluated a new hydrophobic coating—modified polyurea hydrophobic coating (MPHC). MPHC features strong adhesion, high hydrophobicity and excellent durability. The coating performance was evaluated through contact angle measurement, tensile bond strength test, and assessment of environmental durability under several aging conditions including immersion, heat resistance and freeze–thaw cycles. The experimental results showed that the surface contact angle of MPHC reached 131.2°, demonstrating strong hydrophobicity. After durability testing, there was no significant decrease in contact angle and bond strength, confirming the robustness of the coating. The coating combines a “dual structure” formed by polydimethylsiloxane and microsilica powder, thereby creating a hydrophobic rough surface. This structure minimizes the fluid–solid interface area and adhesion, thereby enhancing drag reduction performance. In drag reduction tests on channel model linings, compared with ordinary concrete, MPHC reduced the roughness coefficient by 10.0–11.6%, and by 7.4–7.5% compared with ordinary polyurea coatings. The outstanding hydrophobicity, durability and drag reduction performance of MPHC make it a promising solution for improving the water conveyance efficiency of concrete-lined channels.

Accurately predicting pipe jacking thrust and addressing the limited applicability of existing frictional resistance models under rock formation conditions are key technical challenges in pipe jacking through sandstone formations. Based on a pipe jacking project in the sandstone formation of the Qianping Irrigation District in Henan Province, laboratory direct shear tests were conducted to systematically compare the interface friction characteristics of smooth planar and rough split-surface interfaces under dry-friction and slurry-lubricated conditions. Numerical simulations were subsequently performed using the section beneath Provincial Highway S243 as a representative case. The test results showed that, under dry-friction conditions, the planar interface exhibited a distinct peak, followed by a sudden drop and subsequent stabilization. In contrast, the rough split-surface interface exhibited typical strain-hardening behavior. Slurry lubrication reduced the friction coefficient of the planar interface by 36%; however, under the same lubrication conditions, the friction coefficient of the rough split-surface interface was 20% higher than that of the planar interface. The numerical results indicated that the contact state at the pipe–rock–slurry interface gradually evolved from an initially suspended, noncontact state to localized line contact and then to combined multipoint and multiline contact, ultimately developing into a widespread contact pattern in which the crown, invert, and sidewalls jointly carried the load. The simulated pipe jacking thrust agreed well with the field measurements, whereas the frictional resistance calculated using conventional empirical formulas was substantially higher than the measured values. This finding confirms that the conventional assumptions of uniform contact and constant friction systematically overestimate the actual frictional resistance encountered during pipe jacking through rock formations. By elucidating the dynamic evolution of the pipe–rock interface, this study advances the understanding of the mechanical behavior of pipe jacking in sandstone formations and provides a reliable engineering reference for the accurate prediction of pipe jacking thrust and the optimization of pipe jacking equipment.