Application and Mechanism Study on Optimal Design of Cement-Based Building Materials Based on Polymer Binder

This study examines the effects of three polymer binders—polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyacrylic acid (PAA) on the mechanical properties and dry–wet cycle corrosion resistance of cement mortar at different dosages (1–4%). Mechanical testing combined with scanning electron microscopy (SEM) and molecular dynamics (MD) simulations was conducted to validate the experimental findings and reveal the underlying mechanisms. Results show that polymers reduce early-age strength but improve flexural performance, and at low dosage, enhance compressive strength. PVA and PAA exhibited a pronounced improvement in mechanical strength while PVA and PEG showed a significant improvement in wet cycle corrosion resistance. SEM observations indicated that polymers encapsulate cement particles, enhancing interfacial bonding while partially inhibiting hydration. MD simulations revealed that PVA and PAA interact with Ca2+ via Ca-O coordination, while PEG primarily forms hydrogen bonds, resulting in distinct water-binding capacities (PEG > PVA > PAA). These interactions explain the enhanced mechanism of mechanical and dry–wet cycle resistance properties. This work combined experimental and molecular-level validation to clarify how polymer–matrix and polymer–water interactions govern mechanical and durability, respectively. The findings provide theoretical and practical guidance for designing advanced polymer binders with tailored interfacial adhesion and water absorption properties to improve cementitious materials.