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

2012 ◽  
Vol 535-537 ◽  
pp. 1735-1738 ◽  
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.

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

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.

Shrinkage of Blended Cement Pastes with Mineral Additions

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.

scholarly journals Drying Shrinkage and Gel/Space Ratio of Blended Cement Pastes with Fly Ash

2013 ◽  
Vol 25 (10) ◽  
pp. 5675-5677
Author(s):  
Yan Li ◽  
Dao Sheng Sun ◽  
Xiu Sheng Wu ◽  
Ai Guo Wang ◽  
Wei Xu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Blended Cement ◽  
Drying Shrinkage ◽  
Cement Pastes ◽  
Space Ratio

Effects of Packing Density of Micropowders on the Compressive Strength of Cement Pastes

2007 ◽  
Vol 353-358 ◽  
pp. 1394-1397
Author(s):  
Jian Qing Gong ◽  
Han Ning Xiao ◽  
Zheng Yu Huang ◽  
Jiu Su Li ◽  
Rong Kui Cao ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Packing Density ◽  
Cement Pastes

This study was performed to evaluate the effects of micropowders content on the compressive strength of cement-based composite pastes. Granular ground blast slag (GGBS), grade I fly ash (FAI), ultra fine fly ash (UFA) and silica fume (SF) were selected as the micropowders. The compressive strength was tested after 3d, 7d and 28d curing. Results show that the paste containing both UFA and SF has the highest packing density and corresponding excellent compressive strength. The higher the packing density is, the better the compacting and filling effect of micropowders will be, which contributes to developing higher compressive strength of cement-based pastes.

Effect of fly ash fineness on compressive strength and pore size of blended cement paste

2005 ◽  
Vol 27 (4) ◽  
pp. 425-428 ◽  
Author(s):  
Prinya Chindaprasirt ◽  
Chai Jaturapitakkul ◽  
Theerawat Sinsiri
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Pore Size ◽  
Cement Paste ◽  
Blended Cement ◽  
Blended Cement Paste

Changes of the Properties of Cement Paste with Fly Ash Exposed to the High Temperature

2016 ◽  
Vol 677 ◽  
pp. 138-143
Author(s):  
Romana Lovichová ◽  
Pavel Padevět ◽  
Jindřich Fornůsek
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Cement Paste ◽  
Material Properties ◽  
Bound Water ◽  
Material Structure ◽  
Cement Pastes ◽  
Strength In Bending

This paper describes influence of exposure to high temperatures on material properties of cement paste with addition of fly ash. The properties of cement pastes are significant to the assumption behaviour of concrete and concrete structures. In the cement paste containing fly ash, the effect of high temperature up to 600 ° C causes the changes of content in physically bound water and the change in the material structure. The results of research indicate changes that are reflected in the material properties of the cement paste as compressive strength, tensile strength in bending.

HYDRATION KINETICS OF CEMENT PASTE WITH SILICA FUME AND FLY ASH

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Miguel Picornell ◽  
Sameer Hamoush ◽  
Taher Abu-Lebdeh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Regional Analysis ◽  
Testing Machine ◽  
Testing System ◽  
Hydration Kinetics ◽  
Curing Conditions ◽  
Water Curing

This research study investigates the effect of fly ash and silica fume on the cement paste hydration. A total of 350 samples of different percentages of each additive were tested and compared with the controlled cement paste without additives. Testing method includes water curing and vacuum curing conditions and involves the use of Forney Universal Testing Machine and MTS Landmark Servohydraulic Testing System (MTS) for compressive strength; Fourier Transfer Infrared Spectroscopy (FTIR) monitored the hydration with spectra; and Scanning Electron Microscope (SEM) generated images for regional analysis. Compressive strength testing demonstrated that silica fume replacement had the highest overall strength under water curing. Replacement of fly ash exhibited the highest overall strength under vacuum curing. The hydration process was monitored with the use of FTIR and SEM. Signatures of CSH which produce most of the concretes’ strength, has been determined and examined from 3 to 56 days. FTIR and SEM testing showed an increase in the change of CSH area with age. SEM testing revealed the formation of pores, CSH, and CH in images at all ages. The area of CSH grows most in early ages and diminishes over time. It is clear that the method of curing makes a difference in hydration. Results indicated that the area at which the possible formation of CSH was determined from each sample, has increased with respect to time; signifying the increase in strength over the course of testing days.

Silica Fume, Bond Strength, and the Compressive Strength of Mortar

1987 ◽  
Vol 114 ◽  
Author(s):  
David Darwin ◽  
Shen Zhenjia ◽  
Shraddhakar Harsh
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Strain Rate ◽  
Silica Fume ◽  
Strain Rate Sensitivity ◽  
Cement Paste ◽  
Rate Sensitivity ◽  
Cementitious Material ◽  
Strain Rates ◽  
Volume Fractions

ABSTRACTThe strength and strain-rate sensitivity of cement paste and mortar is studied as a function of water-cementitious material ratio (W/C) and silica fume content. W/C's of 0.30 and 0.35 are used for materials without silica fume, while W/C's ranging from 0.336 to 0.436 are used for material containing silica fume. The volume fractions of cement paste matrix and sand are held at 63 and 37 percent, respectively, for all mortars. Strain rates of 30, 3000, and 300,000 microstrain per second are used. The results indicate that materials with silica fume are less strain-rate sensitive of than materials without silica fume. The replacement of cement by silica fume appears to (1) reduce rather than increase the bond strength between cement paste and sand and (2) increase the compressive strength of mortar primarily by increasing the strength of the cement paste matrix.

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