The Microstructure of ggbfs/OPC Habdened Cement Pastes and Some Effects of Leaching

1989 ◽  
Vol 176 ◽  
Author(s):  
I.G. Richardson ◽  
Sally A. Rodger ◽  
G.W. Groves
Keyword(s):  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Microstructural Development ◽  
Cement Pastes ◽  
Granulated Blast Furnace Slag ◽  
Transmission Electron ◽  
Radioactive Waste Repositories ◽  
Waste Repositories ◽  
Low Level Radioactive Waste ◽  
Furnace Slag

ABSTRACTGround granulated blast-furnace slag (ggbfs) /Ordinary Portland cement (OPC) blends are possible materials for use in intermediate and low-level radioactive waste repositories. The microstructural development in neat OPC is described. The effect of increasing the loading of ggbfs on the composition and microstructure of the hardened paste has been examined by a number of techniques, including transmission electron microscopy. The implications for performance are discussed. A ggbfs/OPC 9:1 blend which had been exposed, after normal hydration to aqueous leaching was also examined. Marked changes in the microstructure and composition were observed.

Alkali Activation of Granulated Blast Furnace Slag

2010 ◽  
Vol 158 ◽  
pp. 1-11 ◽  
Author(s):  
Zi Qiao Jin ◽  
Xian Jun Lu ◽  
Shu Gang Hu
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Hydration Product ◽  
Early Age ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

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.

The Porosity and Pore Structure of Hydrated Cement Pastes as Revealed by Electron Micrsocopy Techniques

1988 ◽  
Vol 137 ◽  
Author(s):  
Ian G. Richardson ◽  
Geoffrey W. Groves ◽  
Sally A. Rodger
Keyword(s):  
Blast Furnace ◽  
Electron Microscope ◽  
Pore Structure ◽  
Blast Furnace Slag ◽  
Cement Hydration ◽  
Mercury Porosimetry ◽  
Hydrated Cement ◽  
Cement Pastes ◽  
Transmission Electron ◽  
Furnace Slag

AbstractThe application of transmission electron microscope techniques to the study of cement hydration can reveal the nature of the fine pore structure present in dried cement pastes. Studies of OPC cement pastes and OPC/fly ash or blast-furnace slag blends are presented and compared. Preliminary results of a technique which allows effective imaging of the porosity which is important in permeation, and which is involved in mercury porosimetry measurements, are presented.

Utilization of Ground Granulated Blast-Furnace Slag Seed Crystal in Eco-Cement

2011 ◽  
Vol 250-253 ◽  
pp. 870-874
Author(s):  
Hong Mei Ai ◽  
Jing Wei ◽  
Jun Ying Bai ◽  
Pu Guang Lu
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Sintering Temperature ◽  
Seed Crystal ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
Granulated Blast Furnace Slag ◽  
Lower Temperature ◽  
Furnace Slag

Eco-cement produced from waste concrete was proved to be feasible in early research. The seed crystal of ground granulated blast furnace slag (GGBS) was utilized in this research to lower the sintering temperature of eco-cement clinker. The mineral compositions of clinker with GGBS seed crystal was analyzed by X-ray diffraction (XRD), and the mechanical properties of eco-cement with GGBS seed crystal was also tested. Four main cement minerals were all observed in eco-cement clinker and the compressive strength of the eco-cement pastes can approach to about 66 MPa at 28 curing days. The results showed that GGBS seed crystal was favourable for the formation of cement minerals at a lower temperature. It can help reduce by about 50~100°C for the sintering process of cement clinker. Content of GGBS seed crystal should better be in the rage of 5%~8%, and the suitable sintering temperature should be 1350°C.

Models for Predicting Free Water and Specific Heat of Pastes Containing Ground Granulated Blast Furnace Slag

2016 ◽  
Vol 860 ◽  
pp. 135-139 ◽  
Author(s):  
Arosha Dabarera ◽  
Warangkana Saengsoy ◽  
Kanako Mori ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Blast Furnace ◽  
Specific Heat ◽  
Blast Furnace Slag ◽  
Free Water ◽  
Early Age ◽  
Cement Pastes ◽  
Granulated Blast Furnace Slag ◽  
Free Water Content ◽  
High Specific Heat ◽  
Furnace Slag

This paper aims to investigate early age behavior in terms of free water content and specific heat for hardening cement paste incorporating Ground Granulated Blast Furnace Slag. Experiments were conducted to obtain free water and specific heat of slag-cement pastes by varying water to binder ratios and slag replacement levels. Free water to total binder ratios for pastes with w/b of 0.40 and slag replacements of 45% and 75% are 0.23 and 0.25 at 3 days and 0.17 and 0.19 at 28 days, respectively. Specific heat values for similar mixtures are 0.26 and 0.30 at 3 days and 0.23 and 0.25 at 28 days. Results showed that specific heat decreases as the amount of free water decreases. The slag substitution resulted in high specific heat and free water at early age but tends to decrease in long term due to enhanced reaction kinetics. Models were proposed to compute free water and specific heat by modifying existing models. The model simulations can be used to predict the measured values accurately.

scholarly journals EVALUATING SHEAR STRENGTH OF SAND- GGBFS BASED GEOPOLYMER COMPOSITE MATERIAL

2019 ◽  
Vol 59 (4) ◽  
pp. 305-311 ◽  
Author(s):  
Alaa Hussein Jassim Al-Rkaby
Keyword(s):  
Composite Material ◽  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Soil Improvement ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Unconfined Compression ◽  
Granulated Blast Furnace Slag ◽  
Sand Particles ◽  
Furnace Slag

Geopolymer has been emerging as a novel and sustainable replacement for the traditional soil improvement materials, such as ordinary Portland cement OPC and lime, which have severe environmental impacts. In this paper, a series of unconfined compression and triaxial tests were conducted on sand and sand - ground granulated blast-furnace slag (GGBFS) based geopolymer. A solution of sodium silicate and sodium hydroxide was employed for the geopolymerization process. Results revealed that adding the GGBFS resulted in a significant increase in the strength properties. This result indicates that geopolymer acted as a cementation agent, providing better bonding between the sand particles and consequently improving the performance of the treated sand.

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