This work presents experimental evidence that specific molecular weights of poly(vinyl alcohol) (PVA), a molecule that displays biomimetic ice recrystallization inhibition (IRI) behavior, are required to impart freeze-thaw resistance to portland cement paste when PVA is added as a water-solubilized admixture. Three molecular weights of PVA were first tested for IRI activity. IRI-active PVA-modified cement pastes were then prepared and tested for freeze-thaw resistance. X-ray micro-computed tomography was employed to investigate internal damage and to characterize the air void system. Differential scanning calorimetry was used to quantify and compare the amount of ice that formed in the hardened pastes. Mercury intrusion porosimetry was used to characterize the pore-size distributions of cement pastes. Results substantiate that PVA with a molecular weights >31,000 g/mol can impart freeze-thaw resistance to cement paste and that the freeze-thaw enhancement is not due to improved hydrophobicity or an adequately entrained air void system. PVA additions did lead to reductions in porosity. However, the reductions were insufficient to fully explain why lower quantities of ice formed during freezing, indicating that IRI-active biomimetic polymers, like PVA, can enhance the freeze-thaw resistance of cement paste due, in part, to their interaction with ice.

这项工作提供了实验证据，即当 PVA 作为添加物时，需要特定分子量的聚乙烯醇 (PVA)，一种表现出仿生冰再结晶抑制 (IRI) 行为的分子，以赋予波特兰水泥浆抗冻融性。水溶性混合物。首先测试三种分子量的 PVA 的 IRI 活性。然后制备 IRI 活性 PVA 改性水泥浆并测试其抗冻融性。X 射线微计算机断层扫描用于研究内部损伤和表征气隙系统。差示扫描量热法用于量化和比较硬化糊状物中形成的冰量。压汞法用于表征水泥浆体的孔径分布。结果证实，分子量 > 31,000 g/mol 的 PVA 可以赋予水泥浆体抗冻融性，并且冻融增强不是由于改进的疏水性或充分夹带的气孔系统。PVA 的添加确实导致孔隙率降低。然而，减少量不足以完全解释为什么在冷冻过程中形成的冰量较少，这表明 IRI 活性仿生聚合物（如 PVA）可以提高水泥浆的抗冻融性，部分原因在于它们与冰的相互作用。