Static and Dynamic Experimental Study on High Strength, High Toughness, and High Crack-Bearing Performance of Polyacrylate-Modified Concrete

Conventional cement concrete has difficulty simultaneously achieving relatively high strength, large deformation capacity, and satisfactory post-cracking damage resistance, which limits its further use in demanding pavement applications. This study comprehensively evaluates the strength development, deformation capacity, post-cracking load-bearing behavior, repeated-impact response, fracture performance, and crack-evolution characteristics of a dense polyacrylate-modified concrete (PMC). Under the material composition and curing conditions adopted in this study, the PMC combines relatively high flexural strength with substantially enhanced deformability: its 28 d flexural strength and ultimate flexural strain are 51.5% and 505.1% higher, respectively, than those of conventional concrete, while exhibiting more stable post-cracking load-bearing and crack-propagation behavior. The repeated-impact and fracture responses further show that the material can sustain higher levels of cumulative nominal impact-energy input and provides greater fracture resistance and damage tolerance. SEM observations reveal film-like polymer connections on the surfaces of hydration products; this local morphology is consistent with the macroscopic toughness and stable crack-propagation characteristics, providing an experimental basis for further optimization of high-strength, high-toughness polymer-modified concrete for demanding service scenarios such as heavy-duty pavements and steel bridge-deck pavements.