This study conducted a thorough analysis of energy consumption and greenhouse gas (GHG) emissions in the production of hot mix asphalt. The primary sources of energy usage in asphalt mixes are the heating of aggregates, asphalt, and burners, with aggregate heating accounting for a remarkable 97% of the total energy consumption. The results indicate that low-temperature asphalt mixes offer significant benefits over conventional hot mix asphalt in terms of energy efficiency and GHG emissions, with reductions in carbon dioxide emissions ranging from 18% to 36% and energy savings between 15% and 87%. Additionally, the use of recycled asphalt pavement led to a 12% decrease in carbon dioxide emissions and a 15% reduction in energy consumption. The study further explored the effects of various fuel types on emissions, revealing that replacing fuel oil with natural gas can effectively diminish the carbon footprint of the production process. By optimizing production temperatures and selecting cleaner fuel alternatives, this research highlights the potential for considerable energy savings and emission reductions within the asphalt production sector. These strategies not only promote sustainable road construction practices but also play a vital role in environmental protection and climate change mitigation, advocating for the adoption of innovative technologies in asphalt pavement production.

In this paper, we investigated the internal structure of the beetle elytra, i.e., two different structural forms I and II of the bio-inspired honeycomb column thin-walled structures (BHTS) that give the honeycomb sandwich structure frequently used in construction projects better mechanical properties and lightweight performance. BHTS specimens were fabricated by additive manufacturing selective laser melting (AM-SLM) using AlSi10Mg Al-Si alloy. In order to understand the effect of section angle number on BHTS during loading, quasi-static uniaxial compression tests were carried out and verified by numerical simulation. The experimental results showed that in the quasi-static uniaxial compression tests, the number of section angles greatly improved the energy absorption (EA) index of each BHTS: the average value of initial peak crushing force (PCF) of hexagonal BHTS increased by 108.82% and 43.44%, respectively, compared to triangular and rectangular BHTS. The average value of the mean crushing force (MCF) increased by 74.87% and 45.48%, respectively. The average value of EA increased by 89.02% and 46.64%, respectively. The results indicate that the number of section angles can be used as an effective way to enhance the EA of BHTS. This work can provide a reference for the design of high-efficiency energy absorbers and will be widely used in EA scenarios such as construction, transportation, etc.

The beetle’s elytra have the characteristics of light weight and high energy absorption (EA). In this paper, based on the internal structure of beetle elytra, two bio-inspired honeycomb column thin-walled structures (BHTS) I and II were fabricated by selective laser melting (SLM) technology in additive manufacturing (AM) in order to understand the possible influence of strain rate effect (SRE) on the BHTS under low speed uniaxial compression loading. The influence of three different SREs (0.001 s⁻¹, 0.01 s⁻¹ and 0.1 s⁻¹) on the EA of BHTSs specimens during loading was discussed by means of out-of-plane uniaxial compression tests verified with numerical simulations. The experimental results show that SRE has a significant effect on the EA of BHTSs in low speed out-of-plane uniaxial compression tests: SRE can significantly increase the initial peak crushing force (PCF) and specific energy absorption (SEA) of all types of BHTS specimens. The average increase in PCF/SEA under SRE loading of 0.1 s⁻¹ is 12.70%/9.79% and 17.63 %/11.60%, respectively, compared with 0.001 s⁻¹ and 0.01 s⁻¹. These research methods reduce the use of materials and improve the utilization rate of materials, which can provide important assistance for the design, manufacture and modeling of AM-based materials.

Purpose: As the service time of bridges increases, the degradation of bending capacity, the lack of safety reserves and the decrease in bridge reliability are common in early built bridges. Due to the defective lateral hinge joints, hollow slab bridges are prone to cracking of hinge joint between plates, transverse connection failure and stress of single plates under the action of long-term overload and repeated load. These phenomena seriously affect the bending capacity of the hollow slab bridge. This paper aims to describe a new method of simply supported hollow slab bridge reinforcement called polyurethane–cement (PUC) composite flexural reinforcement.Design/methodology/approach: This paper first studies the preparation and tensile and compressive properties of PUC composite materials. Then, relying on the actual bridge strengthening project, the 5 × 20 m prestressed concrete simply supported hollow slab was reinforced with PUC composites with a thickness of 3 cm within 18 m of the beam bottom. Finally, the load test was used to compare the performance of the bridge before and after the strengthening.Findings: Results showed that PUC has high compressive and tensile strengths of 72 and 46 MPa. The static test revealed that the measured values and verification coefficients of the measured points were reduced compared with those before strengthening, the deflection and strain were reduced by more than 15%, the measured section stiffness was improved by approximately 20%. After the strengthening, the lateral connection of the bridge, the strength and rigidity of the structure and the structural integrity and safety reserves were all significantly improved. The application of PUC to the flexural strengthening of the bridge structure has a significant effect.Originality/value: As a new type of material, PUC composite is light, remarkable and has good performance. When used in the bending strengthening of bridge structures, this material can improve the strength, rigidity, safety reserve and bending capacity of bridges, thus demonstrating its good engineering application prospect.

The slippage of cable clamps during the long-term operation of suspension bridges is a common and detrimental phenomenon. From an experimental point of view, the cable clamp slippage of a suspension bridge was investigated to reveal the effect of this sliding on the force acting on the full bridge. The forces acting on the bridge before and after the slippage were analyzed using a finite element model. The calculation results showed that the cable clamp slippage directly affects the cable forces of the hangers. The hanger cable force decreased by 19.2% when the slippage reached 10.2 cm, while the maximum increase in the cable force of adjacent hangers was 147.7 kN, an increase of 7.25%. The variation of forces in the hanger cable disrupted the force balance of the main girder, thereby producing a torque effect at the corresponding position in the girder, i.e., increased torque. Meanwhile, the slippage affected the axial tension in the main cable and the main girder. The impact of the tower internal force was less than 1%. Hence, the study concluded that the effect of cable clamp slippage is better understood, ensuring the safety of the suspension bridge.

Carbon fiber-reinforced polymer (CFRP) reinforcement technology has been widely used in the reinforcement of reinforced concrete (RC) beams. At this stage, high prestressed CFRP board reinforcement is often used in actual reinforcement. However, most reinforced bridges are designed for a long time, and the design value of the protective layer is low, and it is impossible to achieve a large prestressed tension. Therefore, this paper proposes the reverse-arch method to paste the CFRP board and apply low prestress to strengthen the symmetrical RC beam. Through the three-point forward loading test, the cracking load, ultimate load, crack width, mid-span deflection, strain and failure mode of a reverse-arch method-pasted CFRP board-reinforced beam, a directly pasted CFRP board-reinforced beam and an unreinforced beam are compared. The results show that the load-bearing capacity and stiffness of the test beam can be improved by pasting CFRP plates with anti-arch method, but the ductility of the test beam is reduced. Compared with the unreinforced beam, the maximum cracking load and ultimate load are increased by 56% and 63% respectively. The reverse-arch method can produce low prestress, improve the stiffness and bearing capacity of members, and has a good prospect of engineering application.