Retraction notice to Development of microstructure and chemical composition of hydration products of slag activated by ordinary Portland cement [Mater Charact 87 (2014) 149–158]

In order to stimulate the potential cementitious property of granulated blast furnace slag (GBFS), the ground GBFS sample (Wei Fang Iron and Steel Corporation, China) was activated by lime and gypsum under different dosages. The results showed that lime is an effective activator for the slag, and the optimum dosage of lime is about 10% (w/w) of the slag. At the optimum dosage of lime, the 28 days compressive strength of the lime-slag paste is higher than that of 32.5 ordinary Portland cement (OPC). But, the early age strength (3 and 7 days compressive strength) of the lime-slag paste is lower than that of the OPC. Addition of gypsum can effectively improve the early age strength of the lime-slag paste. At the ratio of gypsum:lime:slag of 8.2:9.2:82.6 (w/w), both the early and long-term compressive strengths of the gypsum-lime-slag paste are higher than that of the OPC. According to XRD, TG-DTA and SEM detections of the hydration products of the lime-slag paste, the gypsum-lime-slag paste and the OPC paste, it reveals that the hydration process of the GBFS-based cementitious material is different from the ordinary Portland cement and the presence of ettringite (AFt) contributes to the early age strength of the pastes. The major hydration product of the OPC paste (<7 days) were measured as ettringite (AFt), but the AFt phase was not detected in the hydration product of the lime-slag paste and the major hydration product of the lime-slag paste was determined as amorphous CSH gel. However, AFt was detected in the hydration products of the gypsum-lime-slag paste in the early stages of hydration, and the formation of AFt is favorable for the early strength improvement of the material.

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Estimation and Measurement of Porosity Change in Cement Paste

ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management, Volume 1 ◽

10.1115/icem2010-40024 ◽

2010 ◽

Author(s):

Eunyong Lee ◽

Haeryong Jung ◽

Ki-jung Kwon ◽

Do-Gyeum Kim

Keyword(s):

Ionic Strength ◽

Portland Cement ◽

Cement Paste ◽

Thermodynamic Model ◽

Ordinary Portland Cement ◽

Type I ◽

Hydration Products ◽

Cement Pastes ◽

Porosity Change ◽

Dissolution Reaction

Laboratory-scale experiments were performed to understand the porosity change of cement pastes. The cement pastes were prepared using commercially available Type-I ordinary Portland cement (OPC). As the cement pastes were exposed in water, the porosity of the cement pastes sharply increased; however, the slow decrease of porosity was observed as the dissolution period was extended more than 50 days. As expected, the dissolution reaction was significantly influenced by w/c raito and the ionic strength of solution. A thermodynamic model was applied to simulate the porosity change of the cement pastes. It was highly influenced by the depth of the cement pastes. There was porosity increase on the surface of the cement pastes due to dissolution of hydration products, such as portlandite, ettringite, and CSH. However, the decrease of porosity was estimated inside the cement pastes due to the precipitation of cement minerals.

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Analysis of Chemical Composition of Portland Cement in Ghana: A Key to Understand the Behavior of Cement

Advances in Materials Science and Engineering ◽

10.1155/2015/349401 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Mark Bediako ◽

Eric Opoku Amankwah

Keyword(s):

Chemical Composition ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Chemical Compositions ◽

Test Results ◽

Brand Name ◽

X Ray ◽

Portland Limestone Cement ◽

Limestone Cement ◽

Construction Works

The performance of Portland cement in concrete or mortar formation is very well influenced by chemical compositions among other factors. Many engineers usually have little information on the chemical compositions of cement in making decisions for the choice of commercially available Portland cement in Ghana. This work analyzed five different brands of Portland cement in Ghana, namely, Ghacem ordinary Portland cement (OPC) and Portland limestone cement (PLC), CSIR-BRRI Pozzomix, Dangote OPC, and Diamond PLC. The chemical compositions were analyzed with X-Ray Fluorescence (XRF) spectrometer. Student’st-test was used to test the significance of the variation in chemical composition between standard literature values and each of the commercial cement brands. Analysis of variance (ANOVA) was also used to establish the extent of variations between chemical compositions and brand name of the all commercial Portland cement brands. Student’st-test results showed that there were no significant differences between standard chemical composition values and that of commercial Portland cement. The ANOVA results also indicated that each brand of commercial Portland cement varies in terms of chemical composition; however, the specific brands of cement had no significant differences. The study recommended that using any brand of cement in Ghana was good for any construction works be it concrete or mortar formation.

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Influence of Nanoscale Barium Hydrosilicates on Composition of Cement Stone

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.683.90 ◽

2016 ◽

Vol 683 ◽

pp. 90-94 ◽

Cited By ~ 5

Author(s):

Anna Nikolaevna Grishina ◽

Evgeniy Valerjevich Korolev

Keyword(s):

Composite Materials ◽

Chemical Composition ◽

Portland Cement ◽

Cement Hydration ◽

Experimental Investigations ◽

Cement Stone ◽

Hydration Products ◽

Efficient Control ◽

Calcium Hydrosilicates ◽

Portland Cement Hydration

The development of new types of composite materials is an important aim for construction. Nanoscale admixtures allow efficient control of the composition and properties. Results of experimental investigations concerning effect of admixture of nanoscale barium hydrosilicates to the chemical composition of hydrated portland cement are discussed in the present work. It is shown that several key processes are taking place during nanomodification. Amount of portlandite in cement stone decreases, and there is also quantity growth of different calcium hydrosilicates CSH (I), CSH (II), riversideite and xonotlite. Influence of composition and storing time of barium hydrosilicates to the ratio of different portland cement hydration products is examined. It is found that admixture of barium hydrosilicates with gross formula BaO•26.47SiO2•nH2O stored for 28 days leads to both reduction of portlandite and accretion of hydrated phase.

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Chemical composition and microstructure of hydration products of hardened white portland cement pastes containing admixtures

Journal of Wuhan University of Technology-Mater Sci Ed ◽

10.1007/s11595-015-1224-4 ◽

2015 ◽

Vol 30 (4) ◽

pp. 758-767

Author(s):

Qiu Li

Keyword(s):

Chemical Composition ◽

Portland Cement ◽

Hydration Products ◽

Cement Pastes ◽

White Portland Cement

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Durability of Bittern-Resisting Cement in High Concentration Brine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.972 ◽

2011 ◽

Vol 197-198 ◽

pp. 972-976

Author(s):

Bing Wen Wang ◽

Yun Bing Hou ◽

Zhi Hua Zhai ◽

Shuai Jie Han

Keyword(s):

Corrosion Resistance ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Resistance Coefficient ◽

Hydration Products ◽

High Concentration ◽

Excellent Performance ◽

Chemical Corrosion ◽

Physical Attack ◽

Brine Environment

Bittern-resisting cement (BR) has more excellent performance to resist physical attack and chemical corrosion in high-concentration brine environment than ordinary Portland cement or sulfate- resisting Portland cement. The durability and chemical stability of bittern-resisting cement are studied under drying-wetting cycles in brine, the microstructure and chemical component of hydration products also are determined by SEM/EDXA. The corrosion resistance coefficient Kf of BR mortar prisms in high-concentration brine for 6 months is over 96%, and the mass loss of mortar prisms after 30 drying-wetting cycles in brine is only 4.3%. SEM/EDXA analysis shows that the microstructure and chemical composition of BR hydration products exposed to high-concentration brine environment is more densely and stable than those of ordinary Portland cement.

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