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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-329-36
September 26, 2018
Josephine Cheung, Elizabeth Burns, Joshua Curto, and Nathan Tregger
The production of sustainable building materials, such as concrete, has drawn increasing attention in the last decade. Breakthroughs in the development of new admixtures, optimized mix designs, innovative concrete management systems, together with a deeper understanding of the best-mode usage of admixtures with different cementitious materials have resulted in the production of sustainable concrete with better performance at a lower cost. This paper presents three approaches for producing sustainable concrete: (1) introduction of a new class of admixture systems that produce control flow concrete or concrete with flow characteristics of self-consolidating concrete (SCC) without using high cement content, (2) minimization of polycarboxylate ether/ester (PCE) and cement usage through better understanding of the interaction between PCEs and sulfates and (3) use of in-transit concrete management systems (iCMS) to consistently deliver concrete that will meet desired specifications with minimal over-design.
10.14359/51711234
SP-329-33
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-329-18
Ming Liu, Jing Chen, Yuxin Gao, Guangjun Zheng, and Jiaheng Lei
Adsorption characteristics of polycarboxylate-based superplasticizers (PCE) on tricalcium silicate (C3S) and its effect on the hydration of C3S were investigated. In addition, the morphology change of Ca(OH)2 in the presence of PCE was also examined. The results showed that the saturated adsorption amount of PCE on C3S is about 6~7 mg/g. Adsorption occurred on C3S surface as well as its hydrates and played an important role on hydration of C3S. Before the induction period, adsorption of PCE promote the hydration of C3S, while during induction period and reduction period, PCE retarded the C3S hydration. The morphology and size of Ca(OH)2 are found to be changed with the adsorption of PCE. The size of Ca(OH)2 crystals is about 0.5~1 μm, while it decreased to 0.2~0.5 μm after PCE modification. This study provides direct evidence for applying PCE to improve the mechanical and durability of concrete.
10.14359/51711216
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