Papers by Author: Zi Chen Lu

Abstract: The shrinkage-reducing type polycarboxylate superplasticizer (SRPCA) has become a hot research issue both at home and abroad for its perfect water-reducing ability, outstanding shrinkage-reducing and slump retaining ability. The effect of ordinary polycarboxylate superplasticizer (PCA) and shrinkage-reducing PCA on the drying shrinkage of cement mortar was studied thoroughly in this paper. The result showed that the SRPCA can effectively reduce the drying shrinkage of cement mortar. Moreover, the shrinkage-reducing mechanism was discussed from the aspect of molecular structure to the solution surface tension and also mortar water retention. It indicated that the solution surface tension had certain impact on the PCA shrinking-reducing ability, meanwhile the perfect water-retaining ability conduce to the shrinking-reducing improvement. esides, the introduction of shrinking-reducing functional groups to the ordinary PCE molecular structure can reduce the polymer solution surface tension, control the air content in the concrete and decrease the drying shrinkage of cement-based materials.

Abstract: The molecular weight and molecular weight distribution (MWD) of polycarboxylate superplasticizer (PCE) was measured by gel permeation chromatograph (GPC) which combined three different detectors, namely refractive index detector (RI), laser light scattering detector (LS) and viscosity detector (VIS). By conducting numerous experiments, what the different peak stand for in the chromatogram was verified and the best sample concentration range in the GPC experiment was also determined. Besides, based on the analysis to the RI chromatogram, the theory on using peak area ratio to denote concentration ratio was put forward. What’s more, the calculation of macromonomer reaction ratio using the peak area in the RI chromatogram was introduced.

Abstract: The structure of the polycarboxylate superplasticizer (PCE) and the relationship between the structure and the performance of PCE were summarized and analyzed. Based on these results achieved so far, the consensus and the unified opinions were presented while the ambiguous and contradictory points were compared and discussed. Furthermore, the different effect on performance caused by different structure such as side chain length, degree of polymerization, side chain density, functional group were discussed systematically. Finally the existing problems and the measures to be taken in the future were proposed