In recent years, with the development of the construction industry and the wide application of concrete materials, the demand for natural resources such as sand and gravel in China has continued to grow. The Xinjiang region is rich in natural desert sand resources due to its large desert area, which are inexpensive and easy to obtain, providing new possibilities for the production of concrete materials. The use of natural desert sand as concrete aggregate not only reduces the cost of construction but also contributes to the protection of the environment and the rational development and utilization of natural resources. However, poor particle gradation in natural desert sand leads to poor concrete properties. In this study, the Dinger–Funk equation was used to optimize the aggregate gradation of natural desert sand from Toksun, Xinjiang, and concrete specimens were prepared for mechanical properties and sulfate erosion resistance tests. The test results show that the four groups of aggregates optimized by the Dinger–Funk equation are better than the single gradation and natural gradation in terms of apparent density, bulk density, void ratio, mechanical properties, and durability of concrete. Where the distribution modulus n = 0.3 was the best, the compressive strength, splitting strength, and flexural strength were increased by 13.14%, 15.71%, and 11.08%, respectively, as compared to the natural gradation. After 90 sulfate erosion and dry–wet cycles, the mass change rate and relative dynamic elastic modulus of concrete specimens first increased and then decreased, and at the distribution modulus n = 0.3, the aggregate particles of 0.3–0.6 mm, 0.6–1.18 mm, and 1.18–2.36 mm accounted for 26.98%, 32.33%, and 40.69%, respectively, and the smallest of the mass change rates of durability was the best.

In cold regions, saline soils can cause dissolution, settlement, and salt expansion of the roadbed under the influence of freeze–thaw cycles, so they need to be stabilized during road construction. In this study, lime, fly ash (FA), and polyacrylamide (PAM) were used to stabilize sulfate saline soils, and the stabilized saline soils were subjected to the unconfined compressive strength test (UCS), splitting test, and freeze–thaw cycle tests (FTs). The stabilization mechanism of the three materials on saline soils was also studied via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS). The test results showed that the addition of lime, FA, and PAM to saline soils can improve the mechanical properties and frost resistance of saline soils. After 28 d of curing, the UCS of FA-, PAM-, and lime-stabilized saline soils increased by at least 55%, 23%, and 1068%, respectively, and the splitting strength increased by at least 161%, 75%, and 2720%, respectively. After five freeze–thaw cycles, the residual strength ratios (BDRs) of the UCS of L2 (lime 8%), F2 (FA 11%), and P2 (PAM 1%) stabilized soils and saline soils were 71.78%, 56.42%, 39.05%, and 17.95%, respectively, and the decreasing trend tended to be stable. The saline soils stabilized by lime and FA were chemically stabilized, and their mechanical properties and frost resistance were better than the physical stabilization of PAM.

The cracking of cement-stabilized macadam (CSM) reflects to the asphalt layer, which is one of the reasons for the failure of pavement performance and structure. Adding asphalt emulsion to CSM can effectively prevent the formation of cracks. The primary purpose of this article is to reveal the effect of asphalt emulsions on the performance of CSM by adding different contents of asphalt emulsion. For this purpose, tests of unconfined compressive strength (UCS), flexural tensile strength (FTS), elastic modulus, and frost resistance were performed on CSM with gradations of CSM-5 and CSM-10 (the maximum particle sizes of the macadam in the gradation composition are 5 mm and 10 mm), respectively. The test results showed that the UCS of CSM decreased with the increment of asphalt emulsion content. The FTS and elastic modulus of CSM increased with the content of asphalt emulsion. Based on the FTS test results, the frost resistance coefficient K_m1, defined according to the CSM splitting strength prior to and subsequent to freeze–thaw, was used to evaluate the frost resistance. The test results showed that the frost resistance of CSM improved with the increase in asphalt emulsion content for the same cement content. In conclusion, adding asphalt emulsion to CSM has positive effects on the FTS, elastic modulus, and frost resistance. Therefore, for the purpose of maintaining the UCS value of CSM, the content of cement should be considered at the same time as the controlling of the content of asphalt emulsion.

With the rapid development of ferrous metallurgy, the production of iron tailings as waste after beneficiation is increasing. Due to the shortage of natural stone in road construction, iron tailings can be used as an alternative material to natural stone in semi-rigid bases. In order to study the feasibility of application of cement stabilized iron tailings (CSIT) in semi-rigid base, unconfined compressive strength (UCS), indirect tensile strength (ITS) and cyclic freeze-thaw tests were carried out on cement stabilized iron tailings (CSIT). The gradation composition and cement content were selected as influencing factors. The results show that under the condition of the same cement content, the UCS and ITS of CSIT are proportional to the particle size in the mixture. In CSIT with the same gradation, the mechanical properties increase with the increase of cement content; CSM-40(B) has a higher UCS and CSM-40(C) has a higher ITS, the frost resistance coefficient of CSIT increases with the increase of cement content and the tendency of frost resistance coefficient decreases with the increase of cement content. The frost resistanceofCSM-40 (B) is better than that of CSM-40 (C) for the same cement content. Therefore, for the use of iron tailings in CSM, a suitable gradation composition and cement content should be selected.

Through a series of experimental studies on the unconfined compressive strength, indirect tensile strength (ITS) and freeze-thaw stability of cylindrical specimens, the feasibility of cement-stabilized iron tailings for semi-rigid bases in road construction is determined.Three variables, including the genesis of the materials from which cement stabilized macadam (CSM) are composed, the granulometric composition of the mineral part and the content of cement, were taken as influencing factors. The experimental study shows that with the increase of cement content, the unconfined compressive strength (UCS) , indirect tensile strength (ITS) and frost resistance all increase. Studies have shown that the content of coarse aggregate affects the strength properties and frost resistance of cement-stabilized macadam materials.

This study combined experimental analysis with deep learning to investigate the effects of curing age, steel slag content, and gradation composition on the mechanical properties of cement-stabilized steel slag (CSSS). The strength evolution patterns and underlying microscopic mechanisms were systematically elucidated. Experimental results showed that CSSS strength grows nonlinearly with curing age, with optimal mechanical performance achieved at a 60% steel slag content. The microstructural evolution characterized by SEM-EDS and XRD revealed that steel slag incorporation promotes the formation of AFt and densifies the gel network. In later curing stages, natural carbonation of Ca(OH)₂ and secondary hydration of reactive steel slag components produce CaCO₃ and additional C-S-H gel, which fill pores and significantly enhance long-term strength. A CNN-GRU-Attention model was developed to predict the unconfined compressive strength (UCS) and splitting tensile strength (STS) of CSSS. In a single data split, the model achieved R² values of 0.9875 for UCS and 0.9911 for STS, with RMSEs of 0.2577 MPa and 0.0234 MPa, and MAEs of 0.2059 MPa and 0.0184 MPa, outperforming all benchmark models. Under rigorous 5 × 5 repeated cross-validation, it maintained the highest average R² (UCS: 0.9417, STS: 0.9329) and the lowest error metrics, confirming its robustness and generalization capability. SHAP and Pearson correlation analyses identified cement content as the primary strength determinant, while steel slag content exhibited a threshold effect, highlighting the importance of prudent gradation control in practical engineering. This study provides both a theoretical foundation and a methodological framework for analyzing variable interactions and predicting the strength development of CSSS.