Portland cement hydration is related to mechanical properties, durability and sustainability of cement concretes, and also to the service level of building and structures. This paper will report an initial understanding of Portland cement hydration under low temperatures based on several laboratorial investigations (e.g. thermal gravity analysis /derivative thermogravimetry and X-ray diffraction). Mechanical behaviours and phase evolution are discussed in this report. Calculation based on Powers’ model in cement hydration was also utilised to analyse the Portland cement hydration process under low temperatures. Research shows that low temperature slows the hydration reaction rate and delays the initial setting time, as a result the mechanical behaviours are also influenced. The mechanical behaviours evolution was in great agreement with the calcium silicate hydrate fraction calculated by Powers' model.

The asphalt pavement texture is vertical asymmetric, and the tread rubber may contact part of pavement surface. Therefore, the tread penetration depth (d) is probably essential for developing a reliable relationship between pavement performance and texture. This study investigated the effect of pavement on d, and simplified the contact by squeezing a rubber plate into three-dimensional (3D)-printing specimens. The 44 specimens were manufactured based on the surface morphologies of pavements and artificial surfaces with characteristics of pavement texture. The specimens’ surfaces were characterised by parameters from ISO-25178. A set of self-designed fixture was mounted on a loading machine to exert precise force. The contact area was recorded by leaving the stain attached to the rubber plate on the specimens’ surface. The value of d was obtained based on the specimens' Abbott–Firestone curves and the measured contact area. The results showed that the parameters focusing on the top topography of the pavement surface always exhibited a strong positive correlation with d. Furthermore, the parameter representing the volume of peak material showed almost the strongest linear relationship with d. The intercept and slope of the linear equations increased with the increase in the loading pressure or decline in the rubber hardness.

Pavement heats the near-surface air and affects the thermal comfort of the human body in hot summer. Because of a large amount of connected porosity of porous Portland cement concrete (PPCC), the thermal parameters of PPCC are much different from those of traditional Portland cement concrete (PCC). The temperature change characteristics of PPCC and the effects on surrounding environment are also different. A continuous 48-hour log of temperature of a PCC and five kinds of PPCC with different porosity were recorded in the open air in the hot summer. The air temperatures at different heights above concrete specimens were tested using self-made enclosed boxes to analyze the characteristics of near-surface air temperature. The output heat flux of different concrete specimens was calculated. The results show that the PPCC has higher temperature in the daytime and lower temperature in the nighttime and larger temperature gradient than the PCC. The air temperature above PPCC is lower than that of PCC after solar radiation going to zero at night. The total output heat flux of PPCC is slightly smaller in the daytime and significantly smaller at night than that of PCC. The results of tests and calculations indicate that PPCC contributes to the mitigation of heating effect of pavement on the near-surface air.

Three-dimensional (3D) parameters are being increasingly used to characterise the pavement macrotexture. This study explores the influence of the evaluation area and sampling interval on the 3D macrotexture parameters. The point clouds of surfaces with different morphologies are captured by a 3D scanner, and is divided into non-overlapping rectangular areas with different sizes. The original point clouds are diluted to obtain data with different sampling intervals. The parameters concerned include the root-mean-square surface height Sq, the root-mean-square surface slope Sdq, the peak density Spd, the arithmetic mean principal curvature Spc, the volume of the peak material Vmp and the volume of the core material Vmc. The results indicate that parameters calculated within an evaluation area of 80*80 mm² can properly represent the macrotexture. The sampling interval influence parameters in the order Spc > Spd > Sdq > Sq, Vmp, Vmc. The conclusions lay the foundation for calculating 3D pavement parameters.

Maintaining good friction performance of highway pavement is important for road safety. The friction is affected by many factors, and the present study investigates the effect of the compactness on the texture and friction of asphalt concrete during the polishing process. Two three-dimensional (3D) texture parameters and the mean texture depth (MTD) were used to characterize the surface texture of AC-13 asphalt concrete. The differences of surface texture are then being analyzed among the pavement in the field, rutting slabs with 97% compactness (RS-97), rutting slabs with 100% compactness (RS-100), and rutting slabs with 103% (RS-103). The rutting slabs were polished by a circular vehicle simulator (CVS). The 3D surface topography, British pendulum number (BPN), and MTD were obtained during the polishing process. Test results show that the surface of the rutting slab can be smoother as the compactness increased from 97% to 103%. During the whole polishing process, the rutting slab with smaller compactness had higher value of the MTD. The impact of compactness on the BPN is insignificant during the polishing process, but rutting slabs with smaller compactness had better friction at high speed as the result of the higher MTD.

Wireless power transfer (WPT) is recognized as a critical technology to advance carbon neutrality in transportation by alleviating charging challenges for electric vehicles and accelerating their adoption to replace fossil fuel. To ensure durability under traffic loads and harsh environments while avoiding vehicle obstructions, WPT primary circuits should be embedded within pavement structures rather than surface-mounted. This study systematically investigated the optimization of magnetite-modified asphalt material composition and thickness for enhancing electromagnetic coupling in WPT systems through integrated numerical and experimental approaches. A 3D finite element model (FEM) and a WPT platform with primary-side inductor–capacitor–capacitor (LCC) and secondary-side series (S) compensation were developed to assess the electromagnetic performance of magnetite content ranging from 0 to 25% and pavement thickness ranging from 30 to 70 mm. Results indicate that magnetite incorporation increased efficiency from 80.3 to 84.7% and coupling coefficients from 0.236 to 0.242, with power loss increasing by only 0.25 W. This enhancement is driven by improved equivalent permeability, which directly enhances magnetic coupling efficiency. A critical pavement thickness of 50 mm was identified, beyond which the reduction in transmission efficiency increased significantly due to magnetic flux dispersion. Additionally, the nonlinear increase in power loss is partially attributed to the significant rise in hysteresis and eddy current losses at elevated magnetite content levels. The proposed design framework, which focuses on 10% magnetite content and a total pavement thickness of 50 mm, achieves an optimal energy transfer efficiency. This approach contributes to sustainable infrastructure development for wireless charging applications.