The performance of asphalt can be improved by adding styrene‐butadiene‐styrene (SBS) copolymer and crumb rubber (CR). This paper investigated the influence of the structure and content of styrene‐butadiene‐styrene (SBS) copolymer on the properties of SBS/CR modified asphalt (SBS/CRMA). These SBS/CRMA were prepared by mixing 90# matrix asphalt, 60 mesh CR powder, and SBS copolymers with two molecular structures, which were tested for penetration, softening point, ductility, and rheology. The complex modulus, phase angle, rutting factor, storage modulus, and dissipation modulus of SBS/CRMA were analyzed with the 64°C frequency sweep tests. The results revealed that the content and structure had significant impacts on the performances of SBS/CRMA, and the advantages of SBS polymer network structure in the modified asphalt system cannot be reflected when the amount of SBS was small. Meanwhile, the high‐temperature stability, low‐temperature tensile resistance, temperature sensitivity, and viscoelasticity of rubberized asphalt were further improved by adding a moderate amount of SBS copolymer. Furthermore, the properties of SBS/CRMA were better as the contents of SBS increased when the type of SBS doped was the same. The effect of modification improved by star‐shaped SBS copolymer addition was more than that improved by linear SBS copolymer addition. As a conclusion, the content of 4 wt% star‐shaped SBS and 20 wt% CR powder‐modified 90# matrix asphalt has the best modification effect with the comparison of other groups.

To achieve dual optimization of the mechanical properties and environmental impacts of geopolymer concrete (GPC), this study proposes a high-strength geopolymer concrete (HSGPC) without coarse aggregate. The mix proportion of HSGPC was optimized using the response surface methodology, targeting compressive strength and splitting tensile strength to determine the optimal mix. Additionally, the carbon emission impact of HSGPC was assessed and compared with ordinary Portland cement concrete, ultra-high-performance concrete, and reactive powder concrete. The results indicate that the optimal mix proportion for HSGPC includes 15% fly ash content, 10.30% silica fume content, alkali activator ratio of 2.5, and a NaOH molar concentration of 10 M. Simultaneously, the carbon emissions of HSGPC are reduced by about 30% compared to ordinary Portland cement concrete. Compared to ultra-high-performance concrete and reactive powder concrete of the same strength, the production of HSGPC respectively reduces carbon emissions by 59.87% and 68.24%. This study not only provides valuable technical support for the practical application of GPC in engineering but also holds significant implications for promoting sustainable development in the construction industry.

The unconfined compressive strength of cement-modified silty sand in Jilin Province was investigated in this study. For this purpose, various tests were conducted, including the screening test, compaction test, CBR test, X-ray fluorescence detection, and unconfined compressive strength test. Effects of compaction degree, soil quality, water quality, cement content, and curing age were considered. The results show that CBR value is positively correlated with compactness. Two kinds of different water qualities have little effect on unconfined compressive strength of cement-improved soil; with the increase in cement content, the unconfined compressive strength increases, and the power function equation established by the two is significantly correlated. The logarithmic relationship between cement-soil strength and curing age is approximately linear. Through regression analysis, the comprehensive characterization parameters of cement-soil strength, such as water-cement ratio, cement content, and curing age, are put forward. The unconfined compressive strength of cement-modified silty sand has a good power function relationship with the comprehensive characterization parameters, and the fitting degree between the strength prediction formula and the existing research and test data exceeds 90%, which verifies the effectiveness of the comprehensive characterization parameters.

To achieve complete wheel alignment parameter detection, it is necessary to unify the axis vectors of the four wheels into the global coordinate system established on the vehicle reference plane. However, in the non-contact measurement system, the existence of non-overlapping fields of view among multiple cameras significantly challenges the global calibration, which is an issue that should be addressed. Consequently, a global calibration method for wheel alignment parameters, grounded in the spatial consistency of optical fields was explored. Firstly, the pose calibration method of the local measurement unit based on the fixed laser planes and dual cameras is studied in se(3). Secondly, the head-to-head and shoulder-to-shoulder calibration methods of camera units without common fields of view based on the joint optimization of the relay optical field and cylindrical target are studied. Finally, the accuracy and stability of the proposed global measurement method without common fields of view are comprehensively verified based on a large reference plate and the verification device as the absolute reference.