controlled release of chemical admixtures in cement based materials
Skip this Video
Download Presentation
Controlled Release of Chemical Admixtures in Cement-Based Materials

Loading in 2 Seconds...

play fullscreen
1 / 33

Controlled Release of Chemical Admixtures in Cement-Based Materials - PowerPoint PPT Presentation

  • Uploaded on

Princeton University April 14, 2008. Controlled Release of Chemical Admixtures in Cement-Based Materials. L. Raki and J. J. Beaudoin. Outline. Our challenge Portland cement and its major phases Basic reactions of cement phases Controlled release-relevant literature

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Controlled Release of Chemical Admixtures in Cement-Based Materials' - ostinmannual

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
  • Our challenge
  • Portland cement and its major phases
  • Basic reactions of cement phases
  • Controlled release-relevant literature
  • Chemical admixtures in concrete
  • CR- a multidisciplinary concept
  • Layered Double Hydroxides
  • Approach
  • Synthesis and analysis of LDHs
  • Admixture delivery – de-intercalation
  • Selected properties of cement paste and mortar containing CR additives
  • Work in progress
  • Concluding remarks
our challenge
Our Challenge

Develop new technologies and innovative solutions for delivery of admixtures in cement systems


Use of nanotechnology approach

Synthesis of novel smart cement-based materials - CR of chemicals

portland cement
Portland Cement
  • Typical Clinker Composition

CaO (67%); SiO2 (22%); Al2O3 (5%); Fe2O3 (3%)

  • Major Phases

- Alite (50-70%): C3S (incorporating Mg2+, Al3+, Fe3+)

- Belite (15-30%): bC2S (incorporating foreign ions)

- Aluminate phases (5-10%): C3A (Si4+, Fe3+, Na+, K+)

- Ferrite phases (5-15%): C4AF (variation in Al/Fe ratio, incorporation of foreign ions)

C=CaO, S=SiO2, A=Al2O3, F=Fe2O3


Interaction of admixtures with the major phases and their hydrates influence the rationale for use of controlled release technology

major cement phases reactions with water
Major Cement Phases – Reactions with Water
  • 2[3CaO.SiO2]+7H2O  3CaO.2SiO2.4H2O+3Ca(OH)2 (C-S-H)
  • 2[2CaO.SiO2]+5H2O  3CaO.2SiO2.4H2O+Ca(OH)2 (C-S-H)
  • 2[C3A]+21H  C4AH13+C2AH8

C4AH13+C2AH8  2C3AH6+9H

  • [C4AF]+16H  C4(A,F)H8

[C4AF] + 16H  C4(A,F)H13 + (A,F)H3



Factors affecting the formation of C-S-H contribute to the rationale for controlled release technology

controlled release of admixtures in cement systems relevant literature
Controlled Release of Admixtures in Cement Systems – Relevant Literature
  • ‘Encapsulation’

C. M. Dry: coated hollow polypropylene fibers used to disperse a corrosion inhibitor (calcium nitrate); Cem. Concr. Res. 28(8),1133, 1998

: Porous aggregate containing antifreeze; Ceram. Trans. v16, 729, 1991

B. R. Reddy et al. : Oil well treating fluids encapsulated in porous solid materials eg. Metal oxides containing accelerators, retarders, dispersants. US. Patent 6, 209, 646, 2001

controlled release of admixtures in cement systems relevant literature8
Controlled Release of Admixtures in Cement Systems – Relevant Literature
  • ‘Intercalation - De-Intercalation’

H. Tatematsu et al.: inorganic and organic cation and anion exchangers eg. Calcium substituted zeolite and hydrocalumite. Exchange of alkali and chloride ion inhibit alkali-aggregate reaction and corrosion of rebar. US. Patent 5,435, 848, 1995.

L. Raki et al.: de-intercalation of layered double hydroxides to control loss of workability in cement-based materials US. Patent Applic. 0022916 A1, 2007

  • ‘In situ chemical reactions’

K. Hambae et al.: addition of substances which hydrolyze under alkaline conditions (pH=12.5) to form cement dispersing agents. EU Patent EP0402319, 1994. US. Patent 5350450, 1994.

chemical admixtures in concrete
Chemical Admixtures in Concrete
  • Water reducers and retarders

(eg. Ca, Na or NH4 salts of lignosulfonic acids)

  • Accelerators

(eg. Alkali hydroxides, silicates, calcium formate, calcium nitrate, sodium chloride)

  • Superplasticizers

- reduce water content

- maintain workability at low water-cement ratio


- poly-b-naphthalene sulfonate

- poly-melamine sulfonates

- carboxylated polymers (polyacrylates or polycarboxylates)

  • The focus of this presentation will be on controlled release (CR) of superplasticizers (SP)
  • CR can mitigate the effects of preferential adsorption of SP by aluminate phases
  • CR can minimize workability loss and extend the practical range of on-site delivery
controlled release of chemicals in various media a multidisciplinary concept
Controlled release of chemicals in various media – a multidisciplinary concept
  • Anion exchange by modifying LDH-type structures:
    • Cement-additive for time controlled delivery of superplasticizers, corrosion inhibitors and other functional admixtures

Other disciplines utilizing LDH’s

    • Delivery carrier for drugs
    • Gene reservoirs
    • CR of plant growth regulators

Layered (L) Double (D) Hydroxides(Hs)

[ M(II)1-x M(III)x (OH)2 ] [ An-x/n , mH2O ] 2 < 1-x/x < 5

Hydroxide Ion

Metal Cation


Layer Thickness0.48nm

M2+, M3+



Gallery Height

structure layered double hydroxide and hydrocalumite
Structure Layered Double Hydroxide and Hydrocalumite

[ M(II)1-x M(III)x (OH)2 ] [ An-x/n , mH2O ] 2 < 1-x/x < 5



Portlandite-type sheets

Brucite-type sheets

V. Rives. Materials Chemistry and Physics 75 (2002), 19

Rousselot et al. Journal of Solid State Chemistry, 167 (2002), 137







CO32- and NO3-


C= 0.82nm






H2O Molecules have been omitted

synthesis of a caal ldh co precipitation technique
Synthesis of a CaAl-LDHCo-precipitation Technique
  • Co-precipitation of corresponding metal nitrate salts at room temperature:
    • Prepare soln.: 0.28 moles Ca(NO3)2.4H2O

0.12 moles Al(NO3)3.9H2O

320 ml distilled water

    • Add dropwise to soln.: 0.6 moles NaOH

0.4 moles NaNO3

 pH 9.6

    • Heat: 16h, 65 °C, Stirring
    • Collect and filter precipitate, washdry 16h at 100 °C in vacuum
synthesis of a caal ldh intercalation of organic molecules
Synthesis of a CaAl-LDHIntercalation of Organic Molecules
  • 2.5g CaAl-LDH dispersed in 250ml of 0.1M aqueous soln of organic salts.
  • Interact under nitrogen with stirring at 65-70 °C
  • Filter, wash with distilled water and acetone, dry 4h at 100 °C

Intercalates include Disal (SNF) superplasticizer

synthesis of a caal ldh organic intercalates cement science
Synthesis of a CaAl-LDHOrganic Intercalates – Cement Science
  • The following organic intercalates were used to form the nanocomposites:
    • 2,6-naphthalene disulfonic acid
    • Naphtalene-2-sulfonic acid
    • Nitrobenzoic acid
    • Disal (SNF superplasticizer)
analysis of ldh s sem
Analysis of LDH’sSEM

Inorganic Host


analysis of ldh s sem22
Analysis of LDH’sSEM



admixture delivery de intercalation nitrobenzoic acid
Admixture Delivery – De-intercalationNitrobenzoic Acid


De-intercalation (0.1M NaOH)

+ (A)


admixture delivery de intercalation nitrobenzoic acid26
Admixture Delivery – De-intercalationNitrobenzoic Acid




Inorganic host

work in progress
Work in Progress
  • Development of new friendly inexpensive method for large scale production of CR composites
  • Development of CR composites containing various types of superplasticizer, citric acid and salicylic acid.
  • Physical/mechanical tests on mortar and concrete
  • Effect of CR nanocomposites on hydration characteristics of cement systems

Concluding Remarks

  • Nano LDH composites have the potential to provide improved controlled release delivery of chemical admixtures in cement-based materials
  • LDH-based technologies are versatile with the potential to utilize through the intercalation mechanism process numerous different admixtures in the same host matrix
  • Controlled-release delivery of all types of superplasticizers in concrete is a promising developing technology