Foam property regulation of ether-type PCE solution through compounding with low-molecular-weight phosphonic acid admixture

Conventional air-entraining agents face a series of problems in cement-based materials, such as poor initial air-entraining ability and poor bubble stability. The size and distribution of bubbles in concrete not only affect the durability of hardened concrete but also have an important influence on the working performance and rheological properties of fresh concrete. Therefore, developing new, highly adaptable, and efficient bubble and rheological regulators is urgently needed. This article studies the effects of two low-molecular-weight admixtures P-1 and P-2 as bubble and rheological regulators on the properties of ether-PCE in aqueous solution and cement paste. Results showed that the air entrainment performance of polymer P-2 is superior to that of polymer P-1 in fresh cement mortar, and the combination of P-2 and PCE produces more bubbles, thereby more effectively reducing the viscosity of the cement mortar, and the difference in hydrophilicity and hydrophobicity between P-1 and P-2 leads to the formation of different aggregation structures in the solution (P-1 is a spherical micelle, and P-2 is a rod-like micelle), which in turn affects its bubble behavior and rheological properties in the cement system. With the use of a foam analyzer, the evolution of bubbles in cement-based materials from solution to mortar was established, and the mechanism of the bubble behavior of phosphonic acid-based block polymers on the rheological properties of ether-type PCE was revealed.