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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-329-33
September 26, 2018
Sean Monkman, Kathryn Grandfield, and Brian Langelier
The addition of carbon dioxide into fresh ready mixed concrete has been observed to produce a measurable increase in hydration and a significant compressive strength increase. An optimal dose introduced during batching and mixing of ready mixed concrete imparts physiochemical changes to the early hydration. The mechanistic basis for macroscopic performance changes was investigated through the study of a model tricalcium silicate system. A C3S paste was treated with carbon dioxide immediately after hydration started. The carbon dioxide reaction products, and the attendant effects, were examined through isothermal calorimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom probe tomography (APT). Carbonate reaction products around 80 nm formed within 60 seconds of the CO2 gas injection. The carbonates were intermixed with silicate reaction products
The addition of carbon dioxide into fresh ready mixed concrete has been observed to produce a measurable increase in hydration and a significant compressive strength increase. An optimal dose introduced during batching and mixing of ready mixed concrete imparts physiochemical changes to the early hydration. The mechanistic basis for macroscopic performance changes was investigated through the study of a model tricalcium silicate system.
A C3S paste was treated with carbon dioxide immediately after hydration started. The carbon dioxide reaction products, and the attendant effects, were examined through isothermal calorimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom probe tomography (APT). Carbonate reaction products around 80 nm formed within 60 seconds of the CO2 gas injection. The carbonates were intermixed with silicate reaction products
10.14359/51711231
SP-329-30
Luigi Coppola, Denny Coffetti, and Elena Crotti
The article deals with the evaluation of the effect of a tartaric acid-based set retarding admixture on the properties of environmentally friendly mortars manufactured with CSA, anhydrite, hydrated lime and supplementary cementitious materials (fly ash, metakaolin and slag cement). Results indicated that the tartaric acid, acts as superplasticizer and it is effective to extend the pot-life of mortars up to about 2 hours. On the other hand, the set-retarding admixture determines a strong retardation of binder hydration and, consequently, a reduction of compressive strength at early ages. Mortars without tartaric acid showed an initial expansion during the first 5-7 days as a consequence of ettringite formation than mixtures shrink. When set-retarding admixture is used, the initial free-expansion totally disappears and shrinkage begins immediately after final set has occurred. However, after 270 days shrinkage is substantially the same for mortars with and without tartaric acid.
10.14359/51711228
SP-329-09
ShanShan Qian, SuPing Cui, ChunYang Zheng, ZiMing Wang, and Yan Yao
In this study, phosphate-based polycarboxylate superplasticizer (PPS) was successfully prepared via precise design and control over the molecular structure. Macromolecules with pendant chlorine groups are synthesized via free radical polymerization (FRP) and atom transfer radical polymerization (ATRP) of 2-hydroxyethyl acrylate, vinylbenzyl chloride and isoamyl alcohol polyoxyethylene ether in the presence of initiator, chain transfer agent and metal complex. The subsequent Arbuzov reaction (AR) between trimethoxyphosphine and chlorine groups of macromolecules gave rise to new type of PPS. The molecular structure of PPS is determined by Fourier Transform Infrared Spectroscopy, 1H Nuclear Magnetic Resonance and Gel Permeation Chromatography, respectively. The surface tension, Zeta potential, adsorption behavior and application performance in concrete are measured. The result shows that PPS we prepared has excellent clay-inerting and high slump retention capability.
10.14359/51711207
SP-329-10
Ying Qiu, Guo-Xin Chen, Ye-Ran Zhu, Xiu-Sheng Tang, and Zheng Cui
A high-performance liquid alkali-free setting accelerator (HSL) in sprayed concrete was prepared by dimethyl sulfoxide modified sepiolite and aluminum hydroxide as the main raw materials. The sprayed concrete rebound have been investigated by concrete penetration resistance tester. Its set accelerating mechanism is studied by pore structure analysis,XRD characterization methods. The pore structure analysis shows that the total porosity and pores larger than 3.94 in. [100 mm] of cement pastes mixed with HSL are slightly reduced after 28 days hydration and the hydration of C3A was accelerated by the polyamine complexation of accelerator, resulting in forming a large number of acicular ettringite and reducing the amount of Ca(OH)2 crystal, which will not affect the later hydration of cement,to improve the final compressive strength. The 1day compressive strength of the concrete mixed with HSL reaches 22.3 MPa (3234 psi), the 28 days compressive strength ratio increasing by 118.5%.
10.14359/51711208
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