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Wang X.,Jiangsu Sobute New Materials Co. | Ran Q.,Jiangsu Sobute New Materials Co. | Yang Y.,Jiangsu Sobute New Materials Co. | Shu X.,Jiangsu Sobute New Materials Co.
Advances in Cement Research | Year: 2016

Polycarboxylate ether superplasticiser (PCE) with different molecular weights but the same length and density of side chains with a block distribution was successfully synthesised through reversible addition-fragmentation chain transfer polymerisation (RAFT). The influence of molecular weight on the performance in cement paste was systematically investigated by measuring the flowability of fresh cement paste, rheology properties, conformation in solution and adsorption characteristics. The results illustrate that when the molecular weight is relatively small, the number of carboxylic groups from the backbone accessible for the cement particle surfaces is too small to have good dispersion. However, PCE with a relatively large molecular weight may be co-precipitated with early cement hydration products owing to rapid adsorption kinetics. Moreover, PCE of much larger molecular weight leads to larger adsorption amounts from the view of both kinetics and thermodynamics. In addition, the flowability and the yield stress are closely related to adsorption amount. An important finding is that the dispersion ability of PCE can be improved with an increase in molecular weight within a certain interval. © 2016, ICE Publishing. All rights reserved.


Ran Q.,Jiangsu Sobute New Materials Co. | Liu J.,Jiangsu Sobute New Materials Co. | Yang Y.,Jiangsu Sobute New Materials Co. | Shu X.,Jiangsu Sobute New Materials Co. | And 2 more authors.
Journal of Materials in Civil Engineering | Year: 2016

The aim of this study was to link the molecular weight (MW) of polycarboxylate superplasticizer (PCE) with the performance of cementitious system for the purpose of developing new products; PCE synthesized by copolymerization of methacrylic acid and methyl poly (ethylene oxide) methacrylate was characterized by proton nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC). The polycarboylate (PC) was separated into four fractions with different MWs using an ultrafiltration method. The interaction behaviors between PC fractions and cement particles were investigated by measuring the adsorption, zeta potential, and hydration. Results showed that PC fractions with medium MW showed a good dispersion and dispersion retention owing to the adsorption amount continuously increasing with time and delayed the longest cement hydration time. The highest MW of PC exhibited poor dispersion and dispersion retention, having the greatest adsorption amount on the cement surface and poor adsorption capacity in the later period, and carried out to promote hydration of cement compared with other polymers. It can be deduced that there was an ideal MWfor the best different performance of the PC investigated. This can provide an important reference for optimizing the process parameters in the preparation. © ASCE.


Li M.,Jiangsu Sobute New Materials Co. | Wang Y.-J.,Nanjing Southeast University | Wang W.-B.,Jiangsu Sobute New Materials Co. | Tian Q.,Jiangsu Sobute New Materials Co. | Liu J.-P.,Nanjing Southeast University
Advances in Cement Research | Year: 2016

The internal curing effect of superabsorbent polymers (SAPs) on high- and ultra-high-performance concrete has been widely acknowledged. For a certain amount of entrained water needed for internal curing, an accurate assessment of the absorption capacity of SAP in cement paste is necessary rather than other solutions to properly proportion the dosage of SAP in cement-based materials, thus attaining their effectiveness in mitigating autogenous shrinkage with fewer adverse effects. In this paper, early-age performances of cement paste with and without SAP, including rate of heat evolution, capillary pressure and rheological properties, are compared, with simultaneous observation of the particle size of SAP in the cement paste. Results indicate that the absorption capacity of SAP in situ can be quantitatively evaluated through the comparison of the rate of heat evolution and capillary pressure from the addition of water to setting. The ideal dosage can be confirmed based on the theoretical amount of entrained water needed for internal curing.


Plank J.,TU Munich | Sakai E.,Tokyo Institute of Technology | Miao C.W.,Nanjing Southeast University | Miao C.W.,Jiangsu Research Institute of Building Science | And 5 more authors.
Cement and Concrete Research | Year: 2015

An overview of current PCE compositions and synthesis methods is provided, followed by novel applications for PCEs including C-S-H-PCE nano-composites and a description of still unresolved challenges for PCE technology. In addition, the functionality of chemical admixtures in specific applications for low-carbon cements and concrete systems is discussed. The action mechanisms of retarders and the recycling system of sludge water by using retarder are introduced. Furthermore, the influence of fluoride ion and the effectiveness of PCE polymers in blended cements and the effect of non-adsorbed polymer are presented. And the impact of special interface modifying materials, of a refined pore structure and of chemical admixtures, particularly shrinkage-reducing agents, is described. The article concludes that more accurate quantitative micro-analytical methods and modeling tools will be needed to obtain a holistic understanding of factors affecting the microstructure of concrete, with the final goal of achieving a more durable concrete. © 2015 Elsevier Ltd.


Wang X.,Jiangsu Sobute New Materials Co. | Ran Q.,Jiangsu Sobute New Materials Co. | Yang Y.,Jiangsu Sobute New Materials Co. | Shu X.,Jiangsu Sobute New Materials Co. | Yu C.,Jiangsu Sobute New Materials Co.
Journal of Materials in Civil Engineering | Year: 2016

Different polycarboxylate (PC) superplasticizers have been successfully synthesized by varying side-chain density as well as sequence structure through free radical polymerization and reversible addition-fragmentation chain transfer polymerization (RAFT), respectively. Characteristic connections between molecular structure and early age properties of cement paste have been systematically evaluated by various methods, such as adsorption, flowability, calorimetric measurements, amount of hydration product, and dissolution of cement grains. The results show that block PC adsorbs faster with a larger adsorption amount onto cement particle surfaces than random PC, thereby having a better initial flowability and faster loss of workability. Moreover, the dormant period of cement paste with block PC could be effectively shortened by 3 h with block PC as well as the onset of the acceleratory period could be promoted. The results from X-ray diffraction (XRD)-Rietveld refinement show that block PC promotes both C3A and C3S reaction than that of random PC. In addition, a larger number of clusters of C-S-H is formed on the cement particle surfaces at the very early age with block PC and then C-S-H clusters developed a continuous structure with prolonged time, which may increase the early strength of cement paste. Furthermore, the dissolution rate of cement minerals is drastically faster with block PC compared with random PC. All these findings are helpful not only for understanding the relationship of the molecular structure of PC and the early age properties of cement paste, but also further designing the optimum molecular structure of PC to meet the requirement of continuous materials with early strength. © 2016 American Society of Civil Engineers.


Plank J.,TU Munich | Sakai E.,Tokyo Institute of Technology | Miao C.W.,Nanjing Southeast University | Miao C.W.,Jiangsu Research Institute of Building Science | And 5 more authors.
Cement and Concrete Research | Year: 2015

An overview of current PCE compositions and synthesis methods is provided, followed by novel applications for PCEs including C-S-H-PCE nano-composites and a description of still unresolved challenges for PCE technology. In addition, the functionality of chemical admixtures in specific applications for low-carbon cements and concrete systems is discussed. The action mechanisms of retarders and the recycling system of sludge water by using retarder are introduced. Furthermore, the influence of fluoride ion and the effectiveness of PCE polymers in blended cements and the effect of non-adsorbed polymer are presented. And the impact of special interface modifying materials, of a refined pore structure and of chemical admixtures, particularly shrinkage-reducing agents, is described. The article concludes that more accurate quantitative micro-analytical methods and modeling tools will be needed to obtain a holistic understanding of factors affecting the microstructure of concrete, with the final goal of achieving a more durable concrete. © 2015 Elsevier Ltd.


Ran Q.,Jiangsu Research Institute of Building Science | Huang Z.,Jiangsu Sobute New Materials Co. | Shu X.,Jiangsu Sobute New Materials Co. | Yang Y.,Jiangsu Sobute New Materials Co. | Zhang Z.,Jiangsu Sobute New Materials Co.
RSC Advances | Year: 2015

High solid-content and low-viscosity poly(acrylamide-co-acrylic acid) aqueous latex dispersions have been successfully synthesized by copolymerization of acrylamide (AM) and acrylic acid (AA) in an aqueous solution of ammonium sulfate (AS) and lithium sulfate (LS) based on a distinctly novel strategy, the so called Swollen-Diffusion-In situ redox Polymerization (SDIP), which involves swelling followed by diffusion and redox initialized polymerization inside the seed particle, avoiding the high viscosity progress resulting from homogeneous nucleation in the continuous phase. Compared to the widely used one stage synthetic protocol, this process affords much more effective control over the viscosity of the dispersion and molecular weight of the resultant polymer by simply changing the concentration of inorganic salts and addition rate of the oxidant. The synthesized aqueous latex dispersions have been characterized using Fourier-transform infrared (FT-IR) spectroscopy, H nuclear magnetic resonance (1HNMR) spectroscopy, and optical microscopy. The mechanism governing the formation of the latex dispersion is also extensively discussed. © The Royal Society of Chemistry 2015.


Patent
Jiangsu Sobute New Materials Co., Jiangsu Research Institute of Building Science, Nanjing Bote Building Materials Co and Jiangsu Bote New Materials Co. | Date: 2014-05-14

The present invention relates to a water-dispersible amphoteric polyurethane and a preparation method for it. The water-dispersible amphoteric polyurethane is prepared from polyisocyanate compound, polyol compound, diol compound containing an anionic group or a potential anionic group, tertiary or quaternary amine cationic group compound containing at least two active H functional groups and polyamine compound containing polyoxyethylene. During preparation, the diol compound and tertiary or low-molecular quaternary amine cationic group compound shall be controlled for the dosing order, and then neutralized and chain-extended to finally get the target product. The present invention further relates to the application of the water-dispersible amphoteric polyurethane in reinforced concrete, wherein the dosing amount is 0.1 - 5% of the total mass of the concrete.


Patent
Jiangsu Sobute New Materials Co. | Date: 2011-12-30

Disclosed is a method for testing the setting time of a cement-based material: testing the capillary negative pressure of a non-bleeding cement-based material, with the time at which the capillary negative pressure reaches a threshold value A as the initial setting time, and/or the time at which the capillary negative pressure reaches a threshold value B as the final setting time, wherein threshold value A is 8-10 kPa, and threshold value B is 54-56 kPa. Alternatively, threshold value A and threshold value B are determined by the following method: formulating a cement-based material for the determination of threshold values with the same raw materials at the same formulation ratio; after vibration-compaction, placing a portion into a measuring mold; after vibration-compaction, testing the capillary negative pressure of the non-bleeding cement-based material placed in the measuring mold; under the same conditions, synchronously testing and determining the initial setting time and final setting time of the cement-based material for the determination of threshold values by a penetration resistance method; the capillary negative pressure corresponding to the initial setting time and final setting time of the cement-based material for the determination of threshold values are respectively threshold value A and threshold value B. The method can not only be used in standard tests for a laboratory cement setting time under standard temperature conditions, but can also be used to realize remote, automatic, and continuous in situ monitoring for the setting time of a cast-in-situ concrete structure.


Patent
Jiangsu Bote New Materials Co., Jiangsu Sobute New Materials Co. and Jiangsu Research Institute of Building Science | Date: 2014-06-25

The present invention relates to a method for testing the setting time of cement-based materials, comprising: test the meniscus depression of cement-based materials without bleeding, take the time when the meniscus depression arrives at threshold A as the initial setting time and/or the time when the meniscus depression arrives at threshold B as the final setting time, wherein threshold A = 8 - 10kPa and threshold B = 54 - 56kPa; or thresholds A and B are determined by the following method: prepare the cement-based materials for the determination of the thresholds through the same mix proportions and raw materials, make the mixture compact by vibration, place some in a test mold and test the meniscus depression of cement-based materials without bleeding in the test mold after compact vibration, under the same conditions, test the initial setting time and final setting time of cement-based materials for determination of the thresholds at the same time by penetration resistance method, wherein the meniscus depressions corresponding to the initial setting time and the final setting time of cement-based materials for the determination of the thresholds are thresholds A and B respectively.

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