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Partial replacement of copper slag with treated crumb rubber aggregates in alkali-activated slag mortar

Ameri, F ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.conbuildmat.2020.119468
  3. Publisher: Elsevier Ltd , 2020
  4. Abstract:
  5. Copper slag (CS) is an industrial waste, which is generally disposed of in landfills, posing threats to the environment. Alternatively, it can be used as natural aggregate replacement in concrete/mortar, however, it results in a significant increase in material density, production and handling cost. The use of crumb rubber in combination with CS can overcome these problems, but there was no prior study on effect of such combination on the properties of alkali activated mortars (AAMs). The primary aim of this study is to address the problem stated above by replacing CS with 5, 10, 15% (by volume) crumb rubber in alkali-activated slag mortars. Furthermore, the effect of pre-treatment of crumb rubber aggregates with sodium hydroxide (NaOH) solution for 1 h and 24 h on workability, compressive strength, flexural strength, water absorption, thermal conductivity, and microstructural properties of mortar mixes was investigated. Based on the test results, the use of crumb rubber resulted in inferior workability and mechanical strength, but better thermal insulating capability as compared to the control mix. Alkali treatment promoted the rubber-binder bond and effectively enhanced the strength of mixes, especially at an early-age (up to 59%), however, alkali treatment for 24 h drastically reduced the workability of fresh mix. Thus, it is recommended to use 10% crumb rubber pre-soaked in NaOH solution for 1 h to achieve acceptable performance. Finally, the economic and ecological analysis results revealed that the produced mortar is beneficial to the environment. © 2020 Elsevier Ltd
  6. Keywords:
  7. Alkali treatment ; Alkali-activated slag mortar ; Copper slag ; Cost analysis ; Crumb rubber ; Aggregates ; Compressive strength ; Concrete aggregates ; Concrete industry ; Copper ; Materials handling ; Mortar ; Slags ; Sodium hydroxide ; Thermal conductivity ; Water absorption ; Acceptable performance ; Alkali activated slags ; Alkali-activated mortars ; Ecological analysis ; Micro-structural properties ; Natural aggregate ; Partial replacement ; Thermal-insulating ; Rubber
  8. Source: Construction and Building Materials ; Volume 256 , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0950061820314732