Properties of green concrete mixes containing metakaolin, micro silica, steel slag, and recycled mosaic tiles

Abstract EN

Recently, the constructions industry begins to make concrete more sustainable, sideby side, with making its high performance.

This paper aims to investigate the effectof (Metakaolin and Micro Silica) when they replace cement by (8, 12 and 16) % and (6, 9 and 12) % respectively, recycled steel slag when replaces fine aggregateby (10, 20 and 30) % , and recycled mosaic tiles when replaces coarse aggregate by(33.33, 66.67 and 100) % each one another on the slump, density, orption andcompressive strength of concrete.

The experimental results showed that themaximum reduction ratio of cement reach (17% ) (8% of metakaolin and 9% MicroSilica) while the optimum percentage of mosaic tiles and steel slag is (100% ) and(20% ) respectively.

The optimum percentages obtained are combining to producethree basic green mixes: 1) 17% (8% of Metakaolin and 9% of Micro Silica) only, (2) A mix containing 17% of (Metakaolin and of Micro Silica) plus 100% ofrecycled mosaic, (3) 17% of (Metakaolin and Micro Silica), 100% of recycledmosaic and 20% of slag.

Compressive strength at (7, 28, and 60) days, modulus ofrupture at (28) days, orption, fresh and hardened density are investigated.

Thebest improvement in compressive strength compared with reference concrete wasrecorded (20.06, 10.855 and 9.983) % at (7, 28 and 60) days respectively for themix containing (17% of cementitious materials plus 100% of recycled mosaic)while the ultimate flexure strength (24) % appeared in green mix containing (17% of cementitious materials, 100% of recycled mosaic and 20% of slag).

Generally, an inverse relationship between density and orption in all trail mixes which areconducted.