ABOUT THE 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.

International Concrete Abstracts Portal

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


Document: 

SP-329-34

Date: 

September 26, 2018

Author(s):

Wolfram Schmidt, Sarah Leinitz, Berta Mota, and Claudia Crasselt

Publication:

Symposium Papers

Volume:

329

Abstract:

The paper presents rheometric results and hydration curves for cementitious systems based on cement mixed with different aqueous phases at solid volume fraction of ϕ = 0.45. The varied aqueous phases were deionized water, limewater, the filter residue of a cement paste mixed at w/c = 2.0, and the filtrate of cement paste at solid volume fraction of 0.45. Each cementitious system provided different amounts and sizes of particles formed in the aqueous phase. The pastes were observed with and without polycarboxylate ether based superplasticizer. It was observed that the presence of particles causes higher PCE saturation dosages to achieve a minimum value, but the minimum value is only affected in the case of large particles. In all cases with and without PCE, the presence of small particles causes increased plastic viscosity. In addition, with decreased number and size of hydrates in the aqueous phase the hydration was retarded, which was specifically pronounced in the presence of PCE.

DOI:

10.14359/51711232


Document: 

SP-329-32

Date: 

September 26, 2018

Author(s):

Jirawan Siramanont and Paul Bowen

Publication:

Symposium Papers

Volume:

329

Abstract:

Calcium Silicate Hydrate (C-S-H) was synthesized with and without D-gluconate in controlled conditions and environment via a dropwise precipitation method. The presence of D-gluconate seems to affect the synthetic C-S-H precipitation. D-gluconate can adsorb on C-S-H and also complex with Ca2+ in solution. The C-S-H stoichiometry in the presence of D-gluconate is different to pure the synthetic C-S-H. The underlying structure of all samples characterized by FTIR and XRD are similar. With the ddition of D-gluconate the C-S-H showed higher weight losses (0.8-4.7%) than the pure synthetic C-S-H. Primary particles show a nanofoil-morphology with or without addition of D-Gluconate.. The D-gluconate modifies the agglomeration patterns, forming hollow square or cuboid aggregates. Higher concentrations of D-gluconate in synthetic C-S-H accentuate this square aggregate shape possibly because of a preferential adsorption onto the synthetic C-S-H basal plane.

DOI:

10.14359/51711230


Document: 

SP-329-31

Date: 

September 26, 2018

Author(s):

Dongmin Wang and Chunlong Huang

Publication:

Symposium Papers

Volume:

329

Abstract:

The durability and mechanical properties of cement-based materials reinforced by nano-SiO2 particles strongly depend on the dispersion characteristics of the nano-SiO2 particles in the cement pore solution. This study presents a simple, inexpensive and environmentally friendly method to improve the distribution of colloidal nano-SiO2 particles. Amphoteric polycarboxylate superplasticizer containing a cationic moiety in its backbone, was synthetized under microwave irradiation and introduced onto the surface of colloidal nano-SiO2 particles being negatively charged using electrostatic self-assembly technique. The above method guarantees the formation of a core-shell structure nano-SiO2 particle, wherein the amphoteric polycarboxylate superplasticizer shell exhibits enhanced steric hindrance repulsion and electrostatic repulsion. Moreover, the proposed method application guarantees a higher dispersion stability of colloidal nano-SiO2 in the saturated calcium hydroxide solution, which makes it favorable for the production of cement-based materials.

DOI:

10.14359/51711229


Document: 

SP-329-22

Date: 

September 26, 2018

Author(s):

Kazuki Matsuzawa, Daiki Shimazaki, Hirokatsu Kawakami, and Etsuo Sakai

Publication:

Symposium Papers

Volume:

329

Abstract:

In cement paste with low water-powder ratio, non-adsorbed superplasticizer molecules increase the fluidity of paste, but their function is not investigated in detail. This study investigates the influence of non-adsorbed superplasticizer on the fluidity of cement paste using several superplasticizers having different molecular structures. The paste consisted of belite-rich low-heat Portland cement, ultra-fine silica particle, and polycarboxylate-based superplasticizer solution. First, a superplasticizer having moderate amount of functional groups was added to the paste, and adsorption was saturated. Subsequently, another superplasticizer was added. The influence of subsequent addition was related to the molecular structure of another superplasticizer. Another superplasticizer having few functional groups decreased adsorption of the first superplasticizer but the fluidity did not change. Another superplasticizer having moderate functional groups did not change adsorption but increased the fluidity. Another superplasticizer having many functional groups increased adsorption but decreased the fluidity.

DOI:

10.14359/51711220


12345...>>

Results Per Page