Influence of novel shrinkage‐reducing polycarboxylate superplasticizer on the nature of calcium–silicate–hydrates

Abstract

Currently, a novel shrinkage-reducing polycarboxylate superplasticizer (SR-PCA) is used to control cementitious shrinkage. To clarify its mechanism when applied in cementitious materials, the influence of SR-PCA on the composition, morphology, and structure of synthetic calcium-silicate-hydrate (C-S-H), together with the interaction between SR-PCA and C-S-H at the atomic level, is investigated. For comparison, a commercial polycarboxylate superplasticizer (PCA) is also employed. The results show PCA and SR-PCA can adsorb on the C-S-H surface rather than intercalate into the layers. Compared with PCA, SR-PCA has a milder impact on C-S-H crystallinity. SR-PCA refines the pore structure of C-S-H drastically, whereas PCA loosens the structure by increasing the mesopore volume. In addition, the adsorption effect of SR-PCA on the C-S-H surface is less significant than that of PCA. At the atomic level, this less adsorption of SR-PCA is attributed to the lower adhesion energy of the C-S-H/SR-PCA interface due to the weaker Ca-O bond strength.

The effect of polycarboxylate superplasticizer on the strength and hydration performance of alkali slag building materials

“…The BEC-520 conductivity control instrument was selected to measure the rate of acceleration; NJ-160A building material net slurry mixer (Shanghai Meiyingpu Instrument and Instrument Manufacturing Co, Ltd.), measuring net slurry; JJ-5 building material sand mixer (Shanghai Meiyingpu Instrument and Instrument Manufacturing Co, Ltd.), used to measure the flowability of ASBM slurry; SS-150 scanning electron microscope (Carl Zeiss AG), accelerated voltage of 30 KV, magnification of 150,000 times, to determine hydration products of building materials; LabSpec-4 infrared spectrometer (Carl Zeiss AG), used to determine the strength of building materials; BD600-S peristaltic pump (Baoding Rafer Fluid Technology Co, Ltd.) for sample preparation. Digital display constant temperature water bath pot (Changzhou Putian Instrument Manufacturing Co, Ltd.), HH-1 type [ 11 ].…”

Improvement of shrinkage reducing performance of polycarboxylate superplasticizer by butyl acrylate and its mechanism

“…14,15 Since it was invented in the 1980s, PCE has made great progress and has become one of the key components in the preparation of high-performance concrete. [16][17][18][19][20] A lot of studies [21][22][23][24] show that PCE has a better effect on shrinkage reduction of concrete than other types of water reducing agents such as naphthalene superplasticizer and aliphatic superplasticizer, but the reduction is limited. Lu 25 studied the relationship between the surface tension of PCE solution and the shrinkage of mortar, and found that reducing the surface tension of PCE solution can effectively reduce the volume shrinkage of concrete.…”

“…Polycarboxylate superplasticizer (PCE) has the advantages including high water reducing rate, low dosage, designability of molecular structure, environmental friendly influence, and so forth 14,15 . Since it was invented in the 1980s, PCE has made great progress and has become one of the key components in the preparation of high‐performance concrete 16–20 . A lot of studies 21–24 show that PCE has a better effect on shrinkage reduction of concrete than other types of water reducing agents such as naphthalene superplasticizer and aliphatic superplasticizer, but the reduction is limited.…”