Synthesis and characterization on anti-clay polycarboxylate superplasticizer in concrete

To address the issues of low anti-clay performance and high adsorption of ordinary superplasticizer in concrete applications, a novel anti-clay polycarboxylate superplasticizer (Abbreviated as KN-G superplasticizer) was developed. Its structure and properties were characterized using techniques such as infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and X-ray diffraction pattern (XRD). The results indicate that the optimal mass ratio for the synthesized KN-G superplasticizer was monomer: sulfonic acid base: initiator quality: chain transfer agent: hydroxypropyl acrylate=0.808:0.129:0.008:0.008: 0.008:0.007:0.048 under specific conditions, including an acid-to-ether molar ratio of 4.0:1, temperature of 35 °C, solid content of 56%, and drop rate of 4 s/drop. The successful grafting of -SO3H functional groups was confirmed by test results of IR and NMR. At a water-to-cement ratio of 0.45, the disage of montmorillonite and KN-G superplasticizer at 3% and 0.5% of the cement mass, respectively, resulted in the fluidity of mortar with low-quality sand reaching 120 mm, demonstrating the effective anti-clay ability of the KN-G superplasticizer.