Limestone filler implementation in geotechnical concrete mixes-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes the use of limestone filler to reduce the cement content and carbon footprint of geotechnical concrete. The UK project involved 929 diaphragm walls, 18,845 piles, and 85,000 rigid inclusions, with approximately 700,000 m³ of concrete supplied by three suppliers across 13 plants.<br /><br />Three tremie concrete mixes were trialled with limestone filler. The filler additions ranged from 30 to 40 kg/m³, allowing cement content to be reduced while keeping water content unchanged. Lab and plant trials found that the mixes maintained the same strength classes and fresh-concrete properties as the original mixes. Compressive-strength results showed only a low impact, despite the filler mixes having slightly higher water-to-cement ratios and lower cement contents. The presentation notes that results should be compared as trends because the trials used different material batches and took place at different times of year.<br /><br />Updated carbon calculations estimated savings of 5.2–7.4% per cubic metre across the three mixes. Based on the volumes supplied, the total reduction was approximately 863 tonnes of CO₂ equivalent.<br /><br />Limestone filler can provide the fine particles needed to control bleeding and segregation without relying as heavily on cement. The presenter concludes that prescriptive standards can constrain this kind of decarbonization, and advocates performance-based concrete specifications to enable lower-carbon mix designs.

Keywords

limestone filler

geotechnical concrete

cement reduction

carbon footprint

tremie concrete

diaphragm walls

rigid inclusions

compressive strength

CO2 savings

performance-based specifications