The influence of water removal techniques on the composition and microstructure of hardened cement pastes

Collier, N.C.; Sharp, J. H.; Milestone, Neil B.; Hill, J.; Godfrey, I.H.

doi:10.1016/j.cemconres.2008.02.012

Cited by 174 publications

(90 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Oven drying causes a lot of damage and leads to high pore entry sizes. Solvent exchange followed by vacuum drying seems to be the best method to stop the hydration [9,[11][12][13] although isopropanol might affect the very small gel porosity of the C-S-H [14]. Comparison with past results shows the critical or threshold pore entry sizes to be more than one order of magnitude larger for oven dried samples than for samples dried by solvent exchange.…”

Section: Introductionmentioning

confidence: 73%

Evolution of pore structure in blended systems

Berodier

Scrivener

2015

Cement and Concrete Research

253

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f oIn this study, the effect of SCM in the cement paste was isolated by using ternary systems combining Portland cement, quartz and SCM. The results show clear differences in how the hydrates from the reaction of clinker, slag and fly ash fill space. The reaction of slag is more efficient than that of fly ash in modifying the porosity. Our results indicate that Portland cement (PC), slag and fly ash reactions are limited at later ages by the lack of water-filled capillary pores. The higher the space available, with increasing the water/solids ratio, the later the reaction is limited. This explains the lower degree of reaction of SCM in blended systems at high replacement levels.

show abstract

Section: Introductionmentioning

confidence: 73%

Evolution of pore structure in blended systems

Berodier

Scrivener

2015

Cement and Concrete Research

253

View full text Add to dashboard Cite

show abstract

“…For quantitative XRD analysis, hydrated paste samples were crushed to a fine powder by manual 74 grinding in a pestle and mortar without any prior hydration stopping, so as to minimise any damage 75 to phases present 15,16 . The powders were backloaded into 16 mm diameter sample holders and 76 diffraction patterns P P X P MPD 77 C K X-ray source, an X C ator detector and operated at 40kV and 40mA.…”

Section: Methodsmentioning

confidence: 99%

The role of the alumina content of slag, plus the presence of additional sulfate on the hydration and microstructure of Portland cement-slag blends

Whittaker

Zając

Haha

et al. 2014

Cement and Concrete Research

150

View full text Add to dashboard Cite

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract: The effects on composite cements of the aluminium content of slag plus that of additional sulphate, has been investigated. Samples containing cement or composites with 40% replacement by one of 2 different slags, differing in aluminium contents, were prepared. A further blended sample was prepared with additional anhydrite replacing 3%w/w of binder. Slag blended mortars showed comparable strengths to the neat cement system at later ages. Adding slag changed the hydration kinetics of the clinker phases. The addition of sulphate had no effect on slag reactivity but increased that of alite. Slags richer in aluminium resulted in greater incorporation of aluminium into C-S-H and encouraged the presence of hemicarbonate over monocarbonate. The Ca/Si ratios of the C-S-H formed were comparable between the two blends, being marginally lower than that of the neat system. The addition of anhydrite resulted in the adsorption of sulphate onto the C-S-H, plus stabilisation of ettringite. Corresponding Author 8 9 The Role of the Alumina Content of Slag, plus the Presence of AdditionalAbstract 10 The effects on composite cements of the aluminium content of slag plus that of additional sulphate, 11 has been investigated. Samples containing cement or composites with 40% replacement by one of 2 12 different slags, differing in aluminium contents, were prepared. A further blended sample was 13 prepared with additional anhydrite replacing 3%w/w of binder. Slag blended mortars showed 14 comparable strengths to the neat cement system at later ages. Adding slag changed the hydration 15 kinetics of the clinker phases. The addition of sulphate had no effect on slag reactivity but increased 16 that of alite. Slags richer in aluminium resulted in greater incorporation of aluminium into C-S-H and 17 encouraged the presence of hemicarbonate over monocarbonate.

show abstract

“…The early-age hardened grout composition was investigated by casting samples of the control grout and grouts containing either 2% (by weight of cement) sodium phosphate or sodium borate, and hydrothermally curing them at 120°C for 7, 14 and 28 d. After each time interval, hydration was arrested using acetone as a solvent replacement technique (Collier et al, 2008) and the composition was determined by means of X-ray diffraction (XRD) and thermogravimetric analysis/derivative thermogravimetric analysis (TGA/DTG). A Bruker D2 Phaser X-ray diffractometer was operated between 5 and 90°2θ at 2°/min and a Perkin Elmer Pyris 1 thermogravimetric analyser was operated using a heating profile of 30-1000°C at 10°C/min in flowing nitrogen.…”

Section: Sample Analysismentioning

confidence: 99%

Inorganic anions as retarders for deep borehole disposal grouts

Collier

Balboa

Milestone

et al. 2017

Advances in Cement Research

View full text Add to dashboard Cite

Deep borehole disposal (DBD) provides an alternative to comparatively shallow mined repository concepts for many high-level radioactive wastes. Filling the annular space around the waste containers with cement grout will support them during placement and seal against ingress of groundwater. The elevated temperature and pressure ($120°C and 50 MPa) will cause acceleration of grout thickening and setting, so retardation is required. The DBD Research Group at The University of Sheffield has developed grouts based on class G oil well cement that use organic retarders, but their presence may increase the solubility of any radionuclides released from the waste packages. New DBD grout formulations using sodium phosphate and sodium borate as inorganic retarders are reported in this paper. To place the wet grout, the onset of thickening needs to be delayed for at least 4 h. Sodium borate was found to provide this retardation at 90°C (0·75% addition) and nearly retarded sufficiently at 120°C (1% addition). Sodium phosphate did not provide sufficient retardation at either temperature. Neither compounds influenced the phases formed, but may suppress the crystallisation of calcium silicate hydrates. This work demonstrates that the performance of these inorganic materials in this application is inferior to that of organic retarders.

show abstract

The influence of water removal techniques on the composition and microstructure of hardened cement pastes

Cited by 174 publications

References 12 publications

Evolution of pore structure in blended systems

Evolution of pore structure in blended systems

The role of the alumina content of slag, plus the presence of additional sulfate on the hydration and microstructure of Portland cement-slag blends

Inorganic anions as retarders for deep borehole disposal grouts

Contact Info

Product

Resources

About