The incorporation of desert sand-mineral admixture improves the abrasion resistance of concrete. To prolong the service life of assembled concrete channels and mitigate the depletion of river sand resources, the effects of fly ash (FA), silica fume (SF), desert sand (DS), and basalt fiber (BF) on the mechanical properties and the abrasion resistance of concrete were examined, alongside an analysis of their microstructures to elucidate the underlying mechanisms of influence. The results indicated that the abrasion resistance strength of concrete mixed with 10% FA and 0.05% BF alone increased by 80.19% and 81.59%, respectively, compared with ordinary concrete (OC). When SF was added to the concrete at a dosage of 10%, it improved the mechanical properties and the abrasion resistance of the concrete. Furthermore, adding SF resulted in a 12.50% increase in compressive strength and a 12.27% increase in abrasion resistance strength compared to OC. The addition of DS did not significantly enhance the concrete’s abrasion resistance. The combination of ingredients for desert sand concrete (DSC) that provides excellent abrasion resistance was determined using an orthogonal experiment. The optimal mixture consisted of 10% FA content, 10% SF content, 40% DS content, and 0.05% BF content, which increased the abrasion resistance strength by 112.95% compared to OC. Through microscopic analysis, it is found that the width of the interfacial transition zone (ITZ) is an important factor in determining the abrasion resistance of concrete, and a narrower ITZ enhances the concrete’s abrasion resistance. The study’s findings could function as a theoretical reference for the engineering design of DSC.
Chloride erodes steel bars through concrete pores, seriously affecting the durability of reinforced concrete structures. Improving the binding ability to chloride is an important measure. We explored the effects of W/C, curing age, and premixed Cl− concentration on the compressive strength and Cl− binding capacity in cement pastes. The results indicate that a premixed 5% concentration of Cl− can improve the compressive strength, whereas an excessive Cl− negatively impacts the mechanical properties. The total Cl− content in cement pastes is a crucial factor that influences the binding ability of Cl−. When the total Cl− content is within 2% (i.e., the premixed Cl− concentration is 5%), the cement paste has a strong binding ability of Cl−. W/C and curing age indirectly affect the binding ability by affecting the total Cl− content. Furthermore, with the increase in content of Cl−, the adsorption content of Cl− by C-S-H increased, while the proportion of Cl− bound by Fs to the total bound Cl− initially declines and then tends to stabilize. It is worth noting that a premixed concentration of 5% is a “safety limit” for cement paste, but for reinforced concrete, the presence of free Cl− above normative thresholds should not be underestimated.