Effectiveness of Polycarboxylate Superplasticizers in Ultra-High Strength Concrete: The Importance of PCE Compatibility with Silica Fume

Plank, Johann; Schroefl, Christof; Gruber, Mirko; Lesti, Matthias; Sieber, R.

doi:10.3151/jact.7.5

Cited by 187 publications

(89 citation statements)

References 8 publications

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“…Therefore, the metal inventory had not been dispersed effectively or incorporated homogeneously into the cement. Whether the presence of ADVA Cast itself is inhibiting metal encapsulation is unclear, although it is noted that bleed water that does not contain superplasticiser is also not The effectiveness of superplasticisers in dispersing colloidal cement phases has been ascribed to early attachment of the polymer to calcium aluminate (C 3 A), which hinders attachment of sulfate ions to form ettringite (Plank et al, 2009). Over time, the superplasticiser is replaced by sulfate (SO 4 2À ) and the cement gains in strength.…”

Section: Discussionmentioning

confidence: 99%

Behaviour of radionuclides in the presence of superplasticiser

Young

Warwick

Milodowski

et al. 2013

Advances in Cement Research

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Superplasticisers improve the flow properties of fresh cement and offer undoubted benefits to the construction sector. There is concern in the nuclear industry, however, that the presence of a superplasticiser in grout or backfill cement may increase the solubility of radionuclides in the cementitious pore water and/or reduce their adsorption from solution. This paper describes the effect of a commercial, polycarboxylated, polyether comb type superplasticiser on the behaviour of selected metals in blended cements through a series of batch and monolith leach experiments.Results of batch experiments show that the presence of free superplasticiser in solution reduces uptake of nickel ( 63 Ni) and europium ( 152 Eu) by both blast-furnace-slag-and pulverised-fly-ash-modified ordinary Portland cement.Further, metal bound in the presence of free superplasticiser is readily remobilised on exposure to fresh cement solution. Conversely, metal uptake is almost complete and appears irreversible when exposed to hardened cements prepared with superplasticiser as part of the original mix. Monolithic slag cement samples prepared with superplasticiser suffer from bleed, with the surplus water containing a significant proportion of the metals added, including uranium and thorium. Digital autoradiography reveals heterogeneous distribution of radioactivity in the monoliths and demonstrates that the dissolved metals have not been effectively immobilised throughout the specimen. The mobility of thorium may indicate similar behaviour by other tetravalent actinide species, notably Pu(IV) and Np(IV).

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Section: Discussionmentioning

confidence: 99%

Behaviour of radionuclides in the presence of superplasticiser

Young

Warwick

Milodowski

et al. 2013

Advances in Cement Research

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“…This shows that in the present case the required amount of SP can be calculated if the composed surface area of all solid ingredients is known. Nevertheless, the SP dosage depends also on the mineralogy and the surface charge of the fines used (Spiratos et al 2003;Plank et al 2009). Another implication of this result is that the SP requirement is rather related to changes in the specific surface area of the mix than to the concentration (by mass) of the nano-silica addition, as it was previously reported by (Sobolev et al 2006).…”

Section: Fresh Concrete Propertiesmentioning

confidence: 99%

Effects of Nano-silica (NS) Additions on Durability of SCC Mixtures

Quercia¹,

Spiesz

Brouwers

2014

Durability of Reinforced Concrete From Composition to Protection

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In this study, three different types of nano-silica were applied in self-compacting concrete (SCC), one produced by the controlled dissolution of the olivine mineral and two having similar particle size distributions (PSD), but produced through two different processes: fumed powder nano-silica and precipitated silica in colloidal suspension. The influence of the nano-silica on SCC was investigated with respect to the properties of the concrete in fresh (workability) and hardened state (durability properties). Additionally, the densification of the microstructure of the hardened concrete was analyzed by SEM and EDS techniques. The obtained results demonstrate that an efficient use of nano-silica in SCC can improve its durability properties. Considering the reactivity of the different nano-silica studied, the colloidal type showed a higher reactivity at early age, which influenced the final SCC properties.

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“…Park et al (2005) showed that fly ash, finely ground slag and CSF could fill into the voids between cement grains and thus increase the packing density. Plank et al (2009) postulated that the addition of particles finer than cement to fill voids would improve packing and reduce water demand. Sakai et al (2009) revealed that the filling and ball bearing effects of CSF would improve the packing and fluidity of cement paste.…”

Section: Introductionmentioning

confidence: 99%

Roles of Packing Density and Water Film Thickness in Rheology and Strength of Cement Paste

Kwan

Chen

2012

ACT

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Lowering the water/cementitious materials (W/CM) ratio is the key for the production of high-strength concrete and high-performance concrete, but there is a limit to lowering the W/CM ratio because the water added must be enough to fill the voids between solid particles and form water films coating the solid particles. Hence, an increase in packing density of the cementitious materials would allow a lower W/CM ratio to be adopted. This research aims to evaluate the effects of adding superfine cement (SFC) and condensed silica fume (CSF) on the packing density of cementitious materials, and study the roles of packing density and water film thickness in the rheological properties and compressive strength of cement paste. The results showed that the addition of SFC and/or CSF can significantly increase the packing density and water film thickness, and thereby greatly improve the rheological and strength performances of cement paste.

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Effectiveness of Polycarboxylate Superplasticizers in Ultra-High Strength Concrete: The Importance of PCE Compatibility with Silica Fume

Cited by 187 publications

References 8 publications

Behaviour of radionuclides in the presence of superplasticiser

Behaviour of radionuclides in the presence of superplasticiser

Effects of Nano-silica (NS) Additions on Durability of SCC Mixtures

Roles of Packing Density and Water Film Thickness in Rheology and Strength of Cement Paste

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