Filler effect of inert mineral powder in concrete: Dissertation

Anna Kronlöf

Research output: ThesisDissertationMonograph

3 Citations (Scopus)

Abstract

Use of fine inert material powders to minimise water requirement in concrete was studied experimentally and theoretically based on particle packing. Superplasticiser was used through the experiments to allow small particles to fill spaces of their own size class. In lean mixes (cement content 140 - 200 kg/m3) with crushed aggregate use of inert mineral powder lowered water requirement up to 40 l/m3 compared to present technology. With more rounded gravel aggregate the reduction was clearly smaller. The experimental results were investigated with the Linear Packing Density Model (LPDM). Theoretically in densely packed mixes aggregates fill space as dense as possible and cement particles fill the remaining aggregate interspace leaving only minimum space for water. Such a mix has optimal composition, but in practice such mixes are not workable. The true water requirement is far greater than expected based solely on the particle system and more so the closer the particle composition is to the optimum composition. This is because in such mixes the interspaces between aggregate particles are not wide enough to allow cement paste movement. On the contrary, in lean mixes water is free to move in-between aggregate interspaces and in very rich ones the paste content is large enough for paste movement. Therefore in lean and rich mixes water requirement can be understood and calculated by the LPDM. To do this, both cement and aggregate packing must be taken into account by finding the proper value of monosize packing density for each component. The aggregate value was found to depend on mix consistency being approximately 0.50 for gravel and 0.42 for crushed aggregate while the value of cement, 0.36, did not appear to depend on consistency within the frame of the experiments. An empirical method is proposed for predicting water requirement near the optimal composition. Mechanical properties and long term behaviour of concretes with large amounts of inert quartz powder were experimentally studied.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Helsinki University of Technology
Supervisors/Advisors
  • Penttala, Vesa, Advisor, External person
  • Matala, Seppo, Advisor, External person
Award date27 Oct 1997
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5075-7
Publication statusPublished - 1997
MoE publication typeG4 Doctoral dissertation (monograph)

Fingerprint

Fillers
Minerals
Concretes
Powders
Cements
Water
Gravel
Chemical analysis
Quartz
Experiments
Mechanical properties

Keywords

  • concrete
  • aggregates
  • particle packing
  • plasticizers (additives)
  • filling materials
  • fillers

Cite this

Kronlöf, A. (1997). Filler effect of inert mineral powder in concrete: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Kronlöf, Anna. / Filler effect of inert mineral powder in concrete : Dissertation. Espoo : VTT Technical Research Centre of Finland, 1997. 202 p.
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Kronlöf, A 1997, 'Filler effect of inert mineral powder in concrete: Dissertation', Doctor Degree, Helsinki University of Technology, Espoo.

Filler effect of inert mineral powder in concrete : Dissertation. / Kronlöf, Anna.

Espoo : VTT Technical Research Centre of Finland, 1997. 202 p.

Research output: ThesisDissertationMonograph

TY - THES

T1 - Filler effect of inert mineral powder in concrete

T2 - Dissertation

AU - Kronlöf, Anna

PY - 1997

Y1 - 1997

N2 - Use of fine inert material powders to minimise water requirement in concrete was studied experimentally and theoretically based on particle packing. Superplasticiser was used through the experiments to allow small particles to fill spaces of their own size class. In lean mixes (cement content 140 - 200 kg/m3) with crushed aggregate use of inert mineral powder lowered water requirement up to 40 l/m3 compared to present technology. With more rounded gravel aggregate the reduction was clearly smaller. The experimental results were investigated with the Linear Packing Density Model (LPDM). Theoretically in densely packed mixes aggregates fill space as dense as possible and cement particles fill the remaining aggregate interspace leaving only minimum space for water. Such a mix has optimal composition, but in practice such mixes are not workable. The true water requirement is far greater than expected based solely on the particle system and more so the closer the particle composition is to the optimum composition. This is because in such mixes the interspaces between aggregate particles are not wide enough to allow cement paste movement. On the contrary, in lean mixes water is free to move in-between aggregate interspaces and in very rich ones the paste content is large enough for paste movement. Therefore in lean and rich mixes water requirement can be understood and calculated by the LPDM. To do this, both cement and aggregate packing must be taken into account by finding the proper value of monosize packing density for each component. The aggregate value was found to depend on mix consistency being approximately 0.50 for gravel and 0.42 for crushed aggregate while the value of cement, 0.36, did not appear to depend on consistency within the frame of the experiments. An empirical method is proposed for predicting water requirement near the optimal composition. Mechanical properties and long term behaviour of concretes with large amounts of inert quartz powder were experimentally studied.

AB - Use of fine inert material powders to minimise water requirement in concrete was studied experimentally and theoretically based on particle packing. Superplasticiser was used through the experiments to allow small particles to fill spaces of their own size class. In lean mixes (cement content 140 - 200 kg/m3) with crushed aggregate use of inert mineral powder lowered water requirement up to 40 l/m3 compared to present technology. With more rounded gravel aggregate the reduction was clearly smaller. The experimental results were investigated with the Linear Packing Density Model (LPDM). Theoretically in densely packed mixes aggregates fill space as dense as possible and cement particles fill the remaining aggregate interspace leaving only minimum space for water. Such a mix has optimal composition, but in practice such mixes are not workable. The true water requirement is far greater than expected based solely on the particle system and more so the closer the particle composition is to the optimum composition. This is because in such mixes the interspaces between aggregate particles are not wide enough to allow cement paste movement. On the contrary, in lean mixes water is free to move in-between aggregate interspaces and in very rich ones the paste content is large enough for paste movement. Therefore in lean and rich mixes water requirement can be understood and calculated by the LPDM. To do this, both cement and aggregate packing must be taken into account by finding the proper value of monosize packing density for each component. The aggregate value was found to depend on mix consistency being approximately 0.50 for gravel and 0.42 for crushed aggregate while the value of cement, 0.36, did not appear to depend on consistency within the frame of the experiments. An empirical method is proposed for predicting water requirement near the optimal composition. Mechanical properties and long term behaviour of concretes with large amounts of inert quartz powder were experimentally studied.

KW - concrete

KW - aggregates

KW - particle packing

KW - plasticizers (additives)

KW - filling materials

KW - fillers

M3 - Dissertation

SN - 951-38-5075-7

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kronlöf A. Filler effect of inert mineral powder in concrete: Dissertation. Espoo: VTT Technical Research Centre of Finland, 1997. 202 p.