Concrete Mix Design: Advanced-Q & A from Live Webinar (PDF)

Q & A from Live Webinar (PDF)

Pdf Summary

The advanced webinar on concrete mix design focused on questions from the audience regarding various techniques and principles in concrete technology. Attendees raised several pertinent queries, which were addressed by the experts. <br /><br />One question addressed the use of internally cured concrete mixes that substitute sand with specialized absorbent aggregates to enhance pavement durability. The response was positive, recommending a demonstration project for practical insights, with support available from lightweight aggregate providers.<br /><br />Another query revolved around the Tarantula curve aggregate grading technique. Although not personally used by the speaker, it's suggested that it may be suitable for low slump paving with angular intermediate materials and is worth further investigation.<br /><br />A question about the minimum cement requirement for interior floors with a steel trowel finish referred attendees to specific tables in ACI documentation. The tables suggest cement amounts based on aggregate sizes, emphasizing a minimum Portland cement weight for these finishes.<br /><br />The relationship between aggregate and cement ratios for varying MPa design strengths was discussed, suggesting that increasing the paste content necessitates a slight reduction in coarse aggregate.<br /><br />Durability as a quantifiable parameter in concrete mix design remains challenging due to the lack of fully reliable tests, a challenge recognized by industry committees over the years.<br /><br />The necessity of capping water content, alongside water-cement ratios in performance specifications, was argued to be beneficial, though it would require a shift in industry norms.<br /><br />For further reading, resources were recommended, including specific articles and books on aggregate packing techniques and concrete mix design.<br /><br />Lastly, recommendations on specifying a coarseness factor in concrete specification highlighted the importance of considering maximum aggregate size, with a suggested coarseness factor range provided for different nominal aggregate sizes.

Keywords

concrete mix design

internally cured concrete

pavement durability

Tarantula curve

aggregate grading

minimum cement requirement

ACI documentation

MPa design strength

water-cement ratio

aggregate packing techniques