Abstract

This work has launched a comprehensive investigation on the macro performance and micro structure of mass concrete produced with alkali‐active sand slate powder (ASSP) for use as the mineral admixture and a thorough analysis on its technical and economic effects is also conducted. Results indicated ternary blend with hybrid of 5–8 wt.% silica fume (SF) and 15–20 wt.% ASSP has the optimal compressive and flexural strength. ASSP particle participates in hydration, accelerates hydration of cement clinker within 8.5 hours, and reduces the autogenous strain of pastes by 164 × 10−6 in case of dosage less than 25% by mass. Improvement in the mechanical and deformation properties of concrete produced with the hybrid of SF and ASSP is attributed to better particles gradation, compactness enhancement, and transformation in products of hydration. On the whole, it provides another new approach for use of alkali‐active rock after second processing as mineral admixture in hydraulic concrete in terms of good performance and economic effects.

Highlights

  • Mineral admixture is of great importance for improving the performance of fresh and hardened hydraulic concrete and saving cost

  • Great success has been achieved in the prevailing use of fly ash (FA), silica fume (SF), and blast furnace slag [1, 2] as mineral admixture, especially when aggregates are alkali-active [3,4,5]. e Danjiangkou hydropower station, which is a Water Source of South-toNorth Water Diversion project, used blast furnace slag as mineral admixture because flint was detected in the aggregates

  • E flexural strength to compressive strength ratios of the ternary blend of sample coded AF1 lie between those of the single FA and active sand slate powder (ASSP) binary blends when the test age is within 7 days; when the test age extends to the 90th day and the 180th day, the binary blend mortar of P·MH 42.5 and ASSP had a higher ratio of flexural strength to compressive strength, indicating that adding the appropriate amount of ASSP has a positive effect on mortar ductility improvement at the latter stage

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Summary

Introduction

Mineral admixture is of great importance for improving the performance of fresh and hardened hydraulic concrete and saving cost. E Danjiangkou hydropower station, which is a Water Source of South-toNorth Water Diversion project, used blast furnace slag as mineral admixture because flint was detected in the aggregates. Great success has been achieved in the prevailing use of fly ash (FA), silica fume (SF), and blast furnace slag [1, 2] as mineral admixture, especially when aggregates are alkali-active [3,4,5]. Both Xiaolangdi and Jinping I hydropower stations [6] used FA and low-alkali cement as admixture to batch concrete to ensure dam safety. Limestone powder was reported to be effective to inhibit AAR [12]; that is, the expansion ratios at 14 days and 28 days of mortar are both less than 0.10% when more than 45 wt.% of limestone powder, 15 wt.% of limestone powder and 30 wt.% of FA or the combination of 25 wt.% of limestone powder and 25 wt.% of FA are added, respectively. e mechanical property and durability of cement-based materials incorporated with limestone powder have been widely investigated

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