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CONCRETE TECHNOLOGYwww.cpi-worldwide.com CPI %u2013 Concrete Plant International %u2013 3 | 2025%u2022 Replacement of all fine aggregate with MP sand in the 40 MPa concrete produced 25% higher compressive strengthSeveral further concrete trials using modern processed sand have been undertaken and these have consistently shown improved cementitious efficiency of 10-15%. Research is ongoing to assess these technical benefits with three contributing factors most likely:%u2022 More consistent grading and particle shape results in lower water contents for the same workability/consistence level of concrete%u2022 Improved particle shape results in better packing of particles that produces higher density and lower porosity of concrete%u2022 Replacement of dredged fine sand results in higher longer-term concrete strengths since these marine deposits can contain significant salt contaminationConclusionsThe development of chemical admixtures for concrete has to some degree allowed concrete producers to compensate for poorer quality manufactured sands used in concrete. This has in some cases meant that control of quality parameters of these sands has relaxed with grading of the material sometimes being the only measured parameter. When shape and cleanness of manufactured sand are not well controlled there is likely to be a negative effect on concrete properties, which even the best chemical admixtures cannot always resolve.This article shows the technical and economic advantages of investing in modern processing of fine aggregate for concrete. Modern processed sands are now available that not only reduce the amount of natural, fine sand required for blending but can also help lower the cementitious content of concrete. Given the economic and environmental pressures facing concrete production around the world, modern processing technology of sand is starting to have a significant impact. nBibliography1. Mackechnie, James, (2024), PAP7, particle packing and pareto principle in concrete technology, Concrete NZ Conference, Christchurch, New Zealand, November 2024.2. Bayezid, Baten and Garg, Nishant, (2024), Introducing particle shape metric (PSM): A fundamental parameter that encapsulates role of aggregate shape in enhancing packing and performance, Cement and Concrete Research, 182.3. Pilegis, Martins et al, (2016), An investigation into the use of manufactured sand as a 100% replacement for fine aggregate in concrete, Materials, 440.4. Standards New Zealand, AS/NZS 3583.6 (2018) Methods of test for supplementary cementitious materials: Determination of relative water requirement and strength index, Weliington.5. Standards New Zealand, (1986), NZS 3111: Method of test for water and aggregate for concrete: Section 19 %u2013 Method for determining voids content, flow time and percentage oversize material in sand, Wellington.YOUR WET CAST EXPERTSAUTOMACAD.COM 1 450.632.6323CULTIVATE YOUR DIFFERENCE AUTOMATIONTHAT GROWSWITH YOUWITHInnovative solutionsfor forward-thinkers