Improving the chloride binding capacity of cement paste by adding nano-Al2O3: The cases of blended cement pastes

The influence of the way and the volume of adding lime dust to fly ash-cement pastes on chloride physical adsorption capacity, chemical combination capacity and binding capacity of fly ash-cement pastes is investigated by adsorption equilibrium method. The results show that with the volume of lime dust as cement replacement raising, the amount of chloride physically adsorbed by fly ash-cement pastes reduces, while the amount of chloride chemical combining is firstly increase, and then decrease, and it reaches the maximum when the lime dust content is 10% , that of chloride binding is firstly increase, and then decrease, which reaches the maximum when the lime dust content is 5%. In addition, with the volume of lime dust as fly ash replacement increasing , the volume of chloride physically adsorbed by fly ash-cement pastes reduces firstly, and then raises, reaching the minimum when the lime dust content is 6%. Whereas, volume of chloride chemical combining and binding both decrease gradually with the increase of lime dust contents. When the population of lime dust as cement or fly ash replacement is low(less than 15% for cement and 9% for fly ash), effect of lime dust content on chloride binding capacity of fly ash-cement pastes is not obvious (under 7.5%).

Download Full-text

Chloride binding capacity and phase modification of alumina compound blended cement paste under chloride attack

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2020.103537 ◽

2020 ◽

Vol 108 ◽

pp. 103537 ◽

Cited By ~ 2

Author(s):

Yunyao Wang ◽

Zhonghe Shui ◽

Xu Gao ◽

Yun Huang ◽

Rui Yu ◽

...

Keyword(s):

Cement Paste ◽

Binding Capacity ◽

Blended Cement ◽

Chloride Binding ◽

Phase Modification ◽

Chloride Attack ◽

Blended Cement Paste

Download Full-text

Effect of triethanolamine on the chloride binding capacity of cement paste with a high volume of fly ash

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.125612 ◽

2021 ◽

pp. 125612

Author(s):

Yibiao Teng ◽

Songhui Liu ◽

Zhaocai Zhang ◽

Jiangwei Xue ◽

Xuemao Guan

Keyword(s):

Fly Ash ◽

Cement Paste ◽

Binding Capacity ◽

High Volume ◽

Chloride Binding

Download Full-text

Improving the chloride binding capacity of cement paste by adding nano-Al2O3

Construction and Building Materials ◽

10.1016/j.conbuildmat.2018.11.012 ◽

2019 ◽

Vol 195 ◽

pp. 415-422 ◽

Cited By ~ 18

Author(s):

Zhiqiang Yang ◽

Yun Gao ◽

Song Mu ◽

Honglei Chang ◽

Wei Sun ◽

...

Keyword(s):

Cement Paste ◽

Binding Capacity ◽

Chloride Binding

Download Full-text

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

Materials Science Forum ◽

10.4028/www.scientific.net/msf.967.205 ◽

2019 ◽

Vol 967 ◽

pp. 205-213

Author(s):

Faiz U.A. Shaikh ◽

Anwar Hosan

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Cement Paste ◽

Ordinary Portland Cement ◽

Blended Cement ◽

High Volume ◽

Ash Content ◽

Partial Replacement ◽

Nano Silica ◽

Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

Download Full-text

Shrinkage of Blended Cement Pastes with Mineral Additions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.539.55 ◽

2013 ◽

Vol 539 ◽

pp. 55-59

Author(s):

Yi Chen ◽

Wu Yao ◽

Dan Jin

Keyword(s):

Fly Ash ◽

Silica Fume ◽

Cement Paste ◽

Mercury Intrusion Porosimetry ◽

Construction Materials ◽

Blended Cement ◽

Cement Pastes ◽

Mercury Intrusion ◽

Mineral Additions ◽

By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

Download Full-text

Chloride-Binding Capacity of Portland Cement Paste Blended with Synthesized CA2 (CaO·2Al2O3)

Advances in Materials Science and Engineering ◽

10.1155/2018/5418930 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Yunsu Lee ◽

Mingyun Kim ◽

Zhengxin Chen ◽

Hanseung Lee ◽

Seungmin Lim

Keyword(s):

Portland Cement ◽

Cement Paste ◽

Binding Capacity ◽

Water Soluble ◽

Chloride Binding ◽

X Ray Diffraction ◽

Total Chloride ◽

X Ray ◽

Isotherm Equation ◽

Portland Cement Paste

A chloride-binding capacity is the major factor to mitigate the ingress of chloride into concrete. This paper presents the chloride-binding capacity of Portland cement paste containing synthesized CA2 (CaO·2Al2O3). The CA2 was synthesized in the high-temperature furnace and characterized by X-ray diffraction for inspecting the purity. The synthesized CA2 was substituted for Portland cement by 0%, 5%, and 10% by weight, and the NaCl solution was used as an internal chloride, which is assumed as a total chloride. The chloride-binding capacity of cement paste was calculated from a water-soluble chloride extraction method by the application of the Langmuir isotherm equation. And the hydration products were analyzed using X-ray diffraction and thermogravimetric analysis. We demonstrate that the CA2 increases an AFm phase in the Portland cement system, and the incorporation of CA2 consequently enhances the chloride-binding capacity of cement paste samples.

Download Full-text

Dry Shrinkage and Compressive Strength of Blended Cement Pastes with Fly Ash and Silica Fume

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1735 ◽

2012 ◽

Vol 535-537 ◽

pp. 1735-1738 ◽

Cited By ~ 2

Author(s):

Yan Li ◽

Dao Sheng Sun ◽

Xiu Sheng Wu ◽

Ai Guo Wang ◽

Wei Xu ◽

...

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Cement Paste ◽

Blended Cement ◽

Drying Shrinkage ◽

Cementitious Material ◽

Strength Increase ◽

Cement Pastes ◽

Dry Shrinkage

This paper reports the drying shrinkage and compressive strength results of cement pastes with fly ash and silica fume. In this study, Portland cement (PC) was used as the basic cementitious material. Fly ash (FA) and silica fume (SF) were used as cement replacement materials at levels of 0%, 5%, 10%, and 15% , 40%, 35%, 25%, and 15% by weight of the total cementitious material, respectively. The water/cement (PC + FA + SF) ratios (w/c) was 0.28 by weight. The samples produced from fresh pastes were demoulded after a day; then they were cured at 20 ±1°C with 50 ± 3% relative humidity (RH) until the samples were used for drying shrinkage and compressive strength measurement at various ages. The results show that drying shrinkage and compressive strength increase with increasing SF content, and the optimum composition of blended cement pastes is the cement paste with 30% fly ash and 10% silica fume, which possesses lower drying shrinkage values than that of plain cement paste and higher early age strength than that of blended cement pastes with fly ash. Furthermore, a linear relationship is established between compressive strength and drying shrinkage. By comparing the development of compressive strength and the drying shrinkage deformations, it appears possible to predict the drying shrinkage according to the acquired compressive strength.

Download Full-text

Development of chloride binding capacity in cement pastes and influence of the pH of hydration products

Canadian Journal of Civil Engineering ◽

10.1139/l08-089 ◽

2008 ◽

Vol 35 (12) ◽

pp. 1427-1434 ◽

Cited By ~ 22

Author(s):

H. W. Song ◽

C. H. Lee ◽

M. S. Jung ◽

K. Y. Ann

Keyword(s):

Binding Capacity ◽

Steel Corrosion ◽

Cementitious Materials ◽

Chloride Binding ◽

Cement Pastes ◽

Ground Sample ◽

Free Chloride ◽

Pulverized Fuel ◽

Binder Type ◽

Pulverized Fuel Ash

This study deals with the chloride binding capacity of cementitious materials. The binding capacities of ordinary Portland cement (OPC), 30% pulverized fuel ash (PFA), 60% ground granulated blast furnace slag (GGBS), and 10% silica fume (SF) pastes were monitored for 150 d using the water extraction method and the pH of the suspension (ground sample in distilled water) was simultaneously measured at 150 d. Results show that the binding capacity always increased with time, irrespective of binder, and the order of binding capacity with binders was 60% GGBS > 30% PFA > OPC > 10% SF. The pH of suspensions increased with time up to about 10 d, presumably due to a leaching out of alkalis, and then kept a certain value that was dependent on binder type. It was also found that an increase in the concentration of hydroxyl ions, derived from the pH of the suspension, resulted in a decrease in the mole ratio of free chloride to hydroxyl ions, reflecting the lower risk of steel corrosion.

Download Full-text