Investigating the effect of adding bacillus bacteria and nano-clay on cement mortar properties. (December 2022)

• Record Type: Journal Article
• Authors: Amiri, Yasser; Hassaninasab, Shahab; Chehri, Khosrow; Zahedi, Mohsen
• Is Part Of: Case studies in construction materials. Volume 17(2022)
• Publication Date: 2022-12
• Subjects: ACC Accelerated Carbonation Curing -- ASTM American Society for Testing and Materials -- AW Agricultural Waste -- CCA Corn Cob Ash -- CRCA Coarse recycled concrete aggregate -- EDX Energy-Dispersive X-ray spectroscopy -- FA Fly Ash -- FNA Fine natural aggregate -- FRCA Fine recycled concrete aggregate -- GGBFS Ground Granulated Blast Furnace Slag -- Gs specific gravity -- IB Industrial By-products -- LMRC Concrete containing Lime & Mechanically treated Recycled Concrete aggregate -- LMRCA Lime & Mechanically treated Recycled Concrete Aggregate -- MS Microsilica -- OPC Ordinary Portland cement -- POFA Palm Oil Fuel Ash -- PP Polypropylene -- PQC Pavement Quality Concrete -- RAC Recycled Aggregate Concrete -- RCA Recycled Concrete Aggregate -- RHA Rice Husk Ash -- RSA Rice Straw Ash -- SAP Superabsorbent Polymer -- SBA Sugarcane Bagasse Ash -- SEM Scanning Electron microscope -- TS Tensile Strengths -- UCS Uniaxial Compressive Strength -- XR X-ray Diffraction; Biological healing -- Bacillus bacteria -- Nano-clay -- Self-healing concrete; Building materials -- Case studies -- Periodicals; 691.05
• DOI: 10.1016/j.cscm.2022.e01167
• Languages: English
• ISSNs: 2214-5095

Abstract

Abstract: Bacterial deposition is one of the techniques recently used to repair and improve concrete properties. Biological mortar is a mixture of bacteria, aggregates, cement, and a nutrient medium containing calcium salt. These bacteria created bounds in the concrete materials by producing microbiological calcium carbonate. In this study, the effect of biological healing was investigated on the properties of concrete mortars containing nano-clay. For this purpose, the effect of healing by bacillus bacteria on untreated mortar specimens was compared with those containing nano-clay. The specimens were then examined through scanning electron microscopy (SEM), weight gain, permeability, sulfate attack, carbonation, and compressive strength (UCS) tests. The results showed that the bacterial deposition rate increased in specimens containing nano-clay compared to untreated specimens. Also, the permeability rate in the nano-clay-treated specimens in the short term was higher than in untreated specimens; however, in the long term, it was lower than that of the untreated specimens. After coating, specimens containing nano-clay and untreated specimens had better performance against sulfate attack than non-coated untreated specimens. Also, the resistance of mortar in these specimens to this damage increased by 15.2 % and 9.2 %, respectively. Additionally, like sulfate attack, resistance to carbonation in the coated nano-clay treated and untreated specimens increased compared to non-coated untreated specimens by 34 % and 15.9 %, respectively. The UCS of the specimens was investigated in four cases: untreated (control) specimens experienced a 4.3 % reduction in resistance compared to the specimens created by adding nano-clay to the mortar specimen. The strength was increased by 6.7 % in untreated specimens after coating. Finally, the strength increased by 13.5 % in the coasted specimen containing nano-clay.