A comparative study on cement hydration and microstructure of cement paste incorporating aminosulfonate-phenol-salicylic acid-formaldehyde and aminosulfonate-phenol-formaldehyde polymer

In this article, the water-soluble aminosulfonate-phenol-salicylic acid-formaldehyde (AH) polymer and aminosulfonate-phenol-formaldehyde polymer (AS) were incorporated into cement paste, and the effect of AH polymer on cement hydration and microstructure of cement paste was compared with AS polymer by means of isothermal calorimetry, X-ray diffraction, thermal analysis, mercury intrusion porosimetry, and scanning electron microscopy. The test results showed that the incorporation of AH and AS polymers into cement paste retards the rate of hydration reaction and reduces the amount of hydration products at early stages of hydration. The use of AH and AS polymers into cement paste also improves pore structure of cement paste. The pore size distribution of cement paste shifts toward smaller pore size scope. A smaller particle size of hydration product can be found in cement paste with AH and AS polymers. The cement paste with AH and AS polymers has a higher pore volume and total porosity. The surface morphologies of cement paste with AH and AS polymers are looser and more homogeneous than blank cement paste. Moreover, at the same dosage of polymer, the effect of AH polymer on the cement hydration and microstructure of cement paste was more significant than that of AS polymer.