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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 37 Abstracts search results
Document:
SP329
Date:
October 2, 2018
Author(s):
Jiaping Liu, Ziming Wang, Terence C. Holland, Jing Huang, Johann Plank
Publication:
Symposium Papers
Volume:
329
Abstract:
On October 28-31, 2018, the Chinese Ceramic Society and the China Academy of Building Research (CABR), Beijing China, in association with ACI, sponsored the Twelfth International Conference on Superplasticizers and other Chemical Admixtures in Concrete in Beijing China. More than 80 papers from all over the world were received and peer reviewed. A total of 36 refereed papers were accepted for publication in the proceedings of the conference. The proceedings were published by the ACI as SP 329. Also, 54 additional papers were presented at the conference, and were published in the Supplementary Papers Volume. The organizers of the conference were the Chinese Ceramic Society, Beijing and the Committee for the Organization of International Conferences (formerly CANMET/ACI Conferences).
DOI:
10.14359/51712247
SP-329-28
September 26, 2018
Nanxiao Gao, Qianping Ran, and Min Qiao
The shrinkage of concrete can adversely affect not only its fitness for use, but also the durability of concrete structural elements. Compared with traditional PCEs, shrinkage-reducing polycarboxylate superplasticizer (SR-PCE) can decrease the concrete shrinkage. Therefore, it’s a new way to increase the durability of concrete in recent years. In this paper, three novel SR-PCEs were designed and synthesized by the free radical copolymerization of acrylic acid and the macromonomers with hydrophobic poly(ethylene oxide and/orpropylene oxide)-based side chains.The effect of the side chain hydrophobicity on drying shrinkage and dispersion performance for concrete was investigated, and the relationship between side chainhydrophobicity, drying shrinkage and pore solution properties (surface tension and alkali ions concentration)was also studied. Based on these investigations, a new kind of SR-PCE was developed (SR-PCE3). Upon the addition of 0.4% SR-PCE3, the water-reducing rate was about 21.4% and the drying shrinkage of concrete was decreased by 24.0% at 60 days. Introducing hydrophobic group as the side chain into the polymer may be an effective way to change the properties of pore solution significantly with low concentration of SR-PCE and thus solve the contradiction between adsorption dispersing and shrinkage reducing.
10.14359/51711226
SP-329-29
Jinming Wang, Kaiyu Wang, Yongwei Wang, Yongsheng Liu, and Jie Zhang
Ordinary cementitious grout for sleeve coupler of reinforcement splicing cannot be applied normally when the temperature is below 5oC. In this paper, a new type of sleeve cementitious grout with sulphoaluminate cement as the main binding material used in the negative temperature is developed. Besides, the effects of polycarboxylate water-reducing agents, thixotropic agents, superfine beads, plastic expansion agents and antifreeze components on the performance of grouting materials are also studied. The results show that the sleeve cementitious grout studied has good rheological properties and strong ability to resist frost. The compressive strength can still develop even in the environment of -10 oC, and there is no special construction technology required. This reduces significantly the difficulty of the construction of prefabricated building connection in low temperature environment.
10.14359/51711227
SP-329-25
Yanwei Wang, Xin Shu, Yong Yang, Qianping Ran, and Jiaping Liu
Conformational properties of comb-shaped copolymer polyelectrolytes such as polycarboxylate ether-based superplasticizers (PCEs) in aqueous solutions and at liquid/solid interfaces are fundamental to their performances as polymeric dispersants. Pioneering studies of Flatt and coworkers have demonstrated the great relevance of polymer theory to the PCE community. The present work revisits this topic with an emphasis on the semi-flexible characteristics of the anionic backbone decorated with flexible side chains. A simple physical picture, where the backbone adopts a "train-like" conformation on the surface, effectively as a two-dimensional worm-like chain, with the side chains mimicking surface-tethered chains, is presented for PCEs in the strongly adsorbed state.
10.14359/51711223
SP-329-26
Hongxia Zhao, Yanwei Wang, Yong Yang, Xin Shu, Jiaping Liu, and Qianping Ran
Computational simulations have become a powerful tool to investigate the conformational properties of polycarboxylate superplasticizers in solution and at liquid-solid interfaces. Those properties are difficult to measure experimentally. Our group has recently carried out some studies on conformation using the all-atom model to explore the effects of counter-ion species and concentration, solution pH, content of methyl groups, and hydrophobic modifications on polymer properties. Such studies were driven by the experimental work carried out in our group during the course of product development, and have in return provided useful information for an improved understanding of experimental phenomena. In this work, we discuss the conformation properties of superplasticizers performed by all-atom molecular dynamics simulations and the correlation of the microscopic conformation with the experimental phenomena.
10.14359/51711224
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