| EPSRC Reference: |
GR/J52440/01 |
| Title: |
INFLUENCE OF AGGREGATE/CEMENT PASTE INTERFACIAL ZONE ON MOLECULAR TRANSPORT IN CONCRETE |
| Principal Investigator: |
Buenfeld, Professor NR |
| Other Investigators: |
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| Project Partners: |
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| Department: |
Civil & Environmental Engineering |
| Organisation: |
Imperial College London |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
13 March 1994 |
Ends: |
12 September 1996 |
Value (£): |
45,757
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| EPSRC Research Topic Classifications: |
| Civil Engineering Materials |
Materials Characterisation |
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| EPSRC Industrial Sector Classifications: |
| Construction |
Transport Systems and Vehicles |
| Water |
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Summary on Grant Application Form |
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Cement paste within approximately 20mm of aggregate particles in OPC concrete is of higher porosity than bulk cement paste. At low cement paste contents these interfacial zones percolate and this is predicted to result in a dramatic reduction in resistance to molecular transport. This is significant as several authorities are currently considering specifying cement contents below the minimum values in the structural concrete codes. The project objective is to identify the influence of the interfacial zone with respect to water absorption, pressure-induced flow of water and ion diffusion and to determine the optimum cement content for a particular water/cement ratio (w/c) and aggregate grading, to minimise transport. IC would identify and characterise appropriate aggregates allowing NIST (self-funded collaborators) to apply a continuum computer model to predict the aggregate fraction required for percolation. IC would measure the resistance to ion diffusion and water permeation of OPC concretes with aggregate fractions around the predicted percolation values. Interfacial zone thicknesses would be measured in the SEM. NIST would use these results to calibrate the model and would predict minimum cement contents for various aggregate grading and w/c combinations. IC would then subject low, optimum and high cement content concretes to water absorption, pressure-induced flow of water and ion diffusion, with a tracer (possibly caesium chloride) dissolved in the water. SEM would then be used to identify the distribution of the tracer and hence the flow paths dominating for each of the transport processes.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.imperial.ac.uk |