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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-329-23
September 26, 2018
Fei Xiao, Yongwei Wang, Jinhuan Lv, Jie Zhang, and Tongwei Lu
In many parts of the world, the lowest temperature in winter is less than -20 degrees Celsius. It is an important problem in the field of construction engineering to improve the quality of concrete engineering and improve the durability of the structure under extreme climate. This paper introduces the development of ultralow temperature anti freezing pumping admixture. In the experiment, the concrete cured at -4°F (-20 °C) or -13°F (-25°C) for 7 days. And then the specimens were maintained in standard condition for different ages. Mechanical and durability properties of concrete were test in different curing conditions and different ages were studied. Mechanical properties include “negative temperature” compressive and flexural strength. Durability includes anti-permeability performance, dry shrinkage and chloride ion penetration resistance. The experimental data shows that the concrete have good mechanical and durability properties in ultra-low temperature because of the addition of an anti-freezing pumping agent. Compared with ordinary antifreeze, the negative temperature strength of concrete mixed with this ultralow temperature anti freezing pumping agent can be increased by more than 100%. By means of scanning electron microscopy (SEM) and pore size analysis were carried out. The action of this super low temperature anti freezing pumping agent and the frost resistance mechanism of concrete are analyzed.
10.14359/51711221
SP-329-27
Xin Shu, Yanwei Wang, Yong Yang, Xiumei Wang, Qian Zhang, Hongxia Zhao, Qianping Ran, and Jiaping Liu
Rheological properties of cement pastes with polycarboxylate superplasticizers (PCE) containing different hydrophobic groups (styrene, n-butyl acrylate units) at different water to cement ratios (w/c) were investigated. Further investigation on the solution behavior (hydrodynamic radius, solution viscosity) and adsorption behavior revealed the fundamental difference of these PCE samples. At high w/c, the rheological properties of cement pastes primarily depended on the ALT and the differences at constant flow diameter were small. At low w/c, the yield stress primarily depended on the ALT, while the apparent viscosity difference relied on the balance of ALT and solution viscosity. The styrene unit enhanced the backbone stiffness and therefore the adsorption affinity, intrinsic viscosity, yet smaller ALT, therefore reduced the apparent viscosity at a proper dosage. The n-butyl acrylate unit always increased the apparent viscosity of cement pastes.
10.14359/51711225
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
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
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