# Intelligent Design of Pavement Concrete Based on RSM-NSGA-III-CRITIC-VIKOR
## 1 Introduction  
Pavement concrete provides significant cost advantages while delivering superior load-bearing capacity, making it particularly suitable for heavy freight traffic applications [1, 2, 3]. However, these concrete structures increasingly face significant challenges under extreme environments induced by climate change. As [PERSON] reports, material degradation costs approximately $4 trillion USD annually worldwide, with infrastructure failures like premature concrete deterioration in harsh environments contributing significantly to these economiclosses [4]. The UN Sustainable Development Goals (SDG 9: Industry Innovation; SDG 11: Sustainable Cities) mandate urgent improvements in infrastructure resilience, as traditional concrete in these regions incur 23-40% higher life-cycle costs due to premature cracking [5; 6]. Particularly in the Gobi Desert, concrete pavements experience accelerated deterioration under sustained high temperatures (40 \({}^{\circ}\)C) and persistent wind erosion (3.5 m/s), conditions that demand specialized concrete formulations with enhanced performance properties. While parameters like water-cement ratio (W/C), sand ratio, and air-entraining agent (AEA) are known to influence concrete performance, the current understanding of their interactive effects on key performance indicators remains fragmented, particularly for extreme environments. [PERSON]'s [7] research shows that increasing W/C from 0.35 to 0.45 reduces compressive strength from 100 MPa to 55 MPa, with freeze-thaw resistance declining significantly when W/C exceeds 0.45. Studies confirm that low W/C (\(\leq\)0.40) combined with appropriate AEA optimize the strength-durability balance. [PERSON] [8] found that increasing W/C from 0.3 to 0.5 increases total shrinkage by 37.3%, primarily due to easier moisture evaporation in high W/C concrete, intensifying drying shrinkage. [PERSON] and [PERSON] [9] demonstrated that increasing W/C raises capillary porosity, directly affecting concrete strength and durability. [PERSON] [10] verified this pattern, noting that higher W/C not only increases porosity but also alters pore size distribution. [PERSON]'s [11] experiments revealed that reducing the sand ratio by 4% improves 56 d compressive strength by approximately 10%, as coarse aggregates contribute more to compressive strength. [PERSON]'s [12] research showed that sand ratio adjustments directly affect flexural strength in fiber-reinforced concrete. The sand ratio affects shrinkage through aggregate volume changes. [PERSON] [13] found that increasing the sand ratio from 0.3 to 0.6 reduces coarse aggregate volume fraction from 448 L/m\({}^{3}\) to 256 L/m\({}^{3}\), significantly impacting concrete shrinkage behavior. Sand ratio adjustments control aggregate volume fraction and equivalent porosity, directly influencing shrinkage strain development. [PERSON] [11] observed that while higher sand ratios improve concrete density through better particle packing, they simultaneously alter interfacial transition zone characteristics, affecting pore structure distribution. Research [7] indicates that increasing AEA from 1% to 8% reduces compressive strength from 100 MPa to approximately 60 MPa, though moderate AEA significantly enhances freeze-thaw resistance. [PERSON] [14] confirmed that 0.7% dosage optimizes durability without excessive strength loss, while 1.4% dosage causes 30-45% strength reduction. [PERSON] [14] found that excessive AEA causes additional water to remain unhydrated, forming numerous capillary pores that generate tensile stress during moisture loss, inducing shrinkage. Experiments show that moderate AEA provides more uniform stress distribution, while excess promotes shrinkage cracking. [PERSON] [15] demonstrated that different AEA types produce distinct pore characteristics.