Durability characteristics of slag based geopolymer concrete modified with crumb rubber

• Published in: Construction & building materials 2023-11, Vol.404, p.132851, Article 132851
• Main Authors: Orhan, Taha Yusuf, Karakoç, Mehmet Burhan, Özcan, Ahmet
• Format: Article
• Language: English
• Subjects: Crumb rubber; Durability; Geopolymer concrete; Potassium hydroxide; Slag
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.132851

•The mechanical properties of the geopolymer concretes decreased somewhat with CR.•As the CR increased, the permeability of the geopolymer concrete decreased.•CR improved the F-T resistance of geopolymer concrete.•The strength of geopolymer concretes under the influence of sulfates increased. Today, due to the increasing demand in the building sector, the interest of researchers in sustainable building materials is increasing. Geopolymer concretes especially come to the forefront due to energy saving and recycling of waste materials. In this paper, slag based geopolymer concretes were produced by substituting crumb rubber (CR) in different proportions instead of fine aggregate. In the samples using 12 M potassium hydroxide (KOH) as alkali activator, river aggregate was used as aggregate. The 28-day compressive strengths of the samples were between 25.95 MPa and 38.17 MPa, between 9.8 MPa and 11.95 MPa at the end of 300F-T cycles, and between 40.65 MPa and 35.70 MPa in sulfate solutions at the end of 12 weeks. Sulfate (5% Na2SO4 and 5% MgSO4) and freeze–thaw (F-T) (100, 200 and 300 cycles) resistances of the samples cured in the laboratory were determined. As a result of durability tests, the compressive strength, weight changes, sorptivity, water absorption, visual and microstructure analysis of the samples were examined. While the compressive strength of the samples kept in sulfate solutions increased, the compressive strength of the samples exposed to F-T cycles decreased. Sodium sulfate solution caused more strength increase in the samples compared to magnesium sulfate solution. After 300F-T, the strength losses in the samples were over 60%. In general, although the CR slightly reduced the mechanical properties of the control samples, it reduced the permeability of the samples, which increased their durability.