Surface energy is a key material property and can work as a crucial parameter in various mechanical models to predict the moisture sensitivity and fatigue damage of asphalt mixtures. The calculated surface energy values of the aggregate minerals strongly depend on their surface roughness. Therefore, it is very relevant for accurate calculation of surface energy to study the relationship between roughness and surface energy. This study aims to investigate the relationship between surface roughness and surface energy of aggregate minerals. Two minerals—quartz and calcite—were used for this study. The surfaces of the mineral specimens were treated to achieve four levels of roughness. Their surface roughness was described by three roughness parameters. Based on the sessile drop method, an optical tensiometer with a 3D topography module was employed to measure the contact angle and the surface energy of the minerals with different roughness. The influences of surface roughness on the contact angle and the surface energy were then analyzed. The results showed that the contact angle for both quartz and calcite decreases with the increasing surface roughness when it is less than 90° and increases when it is greater than 90°. The Wenzel equation can remove the effect of surface roughness on the contact angles of the minerals. The surface energy of quartz and calcite in the presence of roughness at the microscale would be underestimated when using the measured (apparent) contact angle. The corrected surface energy based on the Wenzel equation must be applied to represent the real surface energy of the minerals.

@en

Having a healthy built environment becomes increasingly important, especially under the effects of COVID-19. This paper intends to combine sustainable goals based on climate change with passive design principles to achieve a healthy built environment regarding the building performance of residential buildings. The Yuedao Residential Community in the Lingnan area was taken as an example for the research. Based on relevant standards of healthy buildings, the thermal, light, and acoustic environment requirements were determined. The methods of building performance simulation and on-site measurement were used to quantify the research object environments. Then, the outcomes were obtained based on these standards. As observed, the thermal environment’s adaptive thermal comfort level was level III. It was hot indoors, but the light and acoustic environments met the requirements. Building designs based on a built environment optimized by external shading systems aim to solve problems through building performance simulation and qualitative analysis. After optimization, the thermal environment improved. According to the literature review, this research focused on a healthy built environment with a sustainable passive design in terms of building performance. A research workflow was established that could be used for more practical research, with abundant research methods. The problems were solved to varying degrees, and the Lingnan architectural culture was preserved. Moreover, this research filled the gap in interactive research on healthy built environments with sustainable passive design regarding building performance@en

The aim of this study was to investigate the effects of different anti-ageing compounds (AACs) on the oxidative stability, rheological and mechanical properties of bitumen. Modified bitumen samples containing six different AAC combinations, with five samples containing Irganox acid (3,5-di-tert-butyl-4-hydoxyphenylpropionic acid), a hindered phenol polymer-based antioxidant, were fabricated and aged under different conditions using a Rolling Thin Film Oven (RTFO) as well as a Pressure Aging Vessel (PAV). The oxidative stabilising performance (anti-ageing) of the AACs was examined using Fourier Transform Infrared (FTIR) Spectroscopy. The effect of the AAC-modified bitumen on different rheological and mechanical properties was investigated - complex viscosity, linear viscoelastic (LVE) properties, fatigue and rutting - using a Dynamic Shear Rheometer (DSR). The results illustrated that all the AAC-combinations examined afforded good oxidative stability to the base bitumen, with outstanding anti-ageing performance achieved by formulations C, D, E and F (Irganox acid:NaMMT, Irganox acid:furfural without or with DLTDP or NaMMT). The rheological results showed that the AAC-modified bitumen samples displayed non-Newtonian characteristics associated with simple thermo-rheological materials. The AAC formulations A (DLTDP:furfural), D (Irganox acid:furfural) and F (DLTDP:Irganox acid:furfural) were shown to significantly strengthen the resistance of the bitumen samples to fatigue cracking. In contrast to Irganox acid:furfural combination, the addition of the NaMMT nanofiller to this mixture was found to enhance the rutting resistance of the aged bitumen samples.

@en