Published date: Apr 13 2020

Journal Title: KnE Engineering

Issue title: REMINE International Conference on Valorization of Mining and Industrial Wastes into Construction Materials By Alkali-activation

Pages: 101–110

DOI: 10.18502/keg.v5i4.6801

Abdelhakim Benhamouda benhamouda.abdelhakim@gmail.comCentre of Materials and Building Technologies (C–MADE/UBI), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201–001 Covilhã, Portugal

João Castro-GomesCentre of Materials and Building Technologies (C–MADE/UBI), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201–001 Covilhã, Portugal

The rheological properties of Portland cement (PC) concrete have been extensively studied and compared with those of alkali-activated concrete (AAC). This study discusses the effect of the liquid to solid ratio on the rheological and mechanical properties of AAM concrete, based on mining waste mud as the binder phase, and compares them with those of Portland cement concrete (PCC). The AAM concrete studied is a mix of coarse aggregate 6/15, two types of sand (finer and coarse sand), and a precursor. The precursor is a mix of 70% tungsten mining waste mud, 15% waste glass and 15% metakaolin. This mix was activated by a combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) and the PCC was a mix of the same aggregate but with cement as binder and water as a liquid. The activator/precursor ratio was studied 0.5, 0.52, 0.54, 0.56 and 0.58. The results obtained show a similar rheological behaviour between AAC and PCC, the workability affected by L/S increases with the increasing ratio L/S in AAC and for L/S=0.5 slump was 6 cm and was 16 cm for L/S =0.58. Regarding the mechanical properties, the results obtained in 7 days showed similar performance in AAC and PCC. The compressive strength also decreases with the increasing of L/S, in AAC with L/S=0.5 the compressive strength was 15.9 MPa and for L/S =0.58 was 10.5.

Keywords: Tungsten mining waste, Rheology, Mechanical properties, Portland cement, alkali-activated concrete

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