Abstract
The incorporation of bio-aggregates such as miscanthus in mineral binder matrices can produce lightweight insulation materials. Bio-aggregate lightweight concretes show peculiar microstructure compared to standard mineral aggregate concretes. This paper evaluates the chemical and mineralogical interactions between miscanthus particles and blends of mineral binders that include hydrated lime (CL90s), natural hydraulic lime (NHL3.5), formulated lime (FLA3.5) and mineral additions such as ground granulated blast furnace slag (GGBS), fly ash (FA) and Portland cement (Ce). The properties and the influence of ternary binder blends made of 75%CL90s, 15%NHL3.5 and 10% mineral additions (GGBS/FA/Ce) on the morphology of the interfacial zone were investigated. It was observed that carbonation of samples proceeds from the outer shell to the inner core of samples leaving a physically identifiable hardened shell (external 1–2 cm) and a softer inner core. In all samples, the X-ray diffraction results show that there is a reduction in peak intensities and broadening of Ca(OH)2 peaks whereas peaks of CaCO3 sharpen and increase in intensity. The mineralogical changes in the binding matrix depend on the type of mineral addition. Thermogravimetric analysis shows that the addition of 10% Portland cement results in the highest levels of carbonation (1.1–1.4%) and hydration (8.6–17.1%). However, also fly ash incorporation was found to be beneficial in terms of reaction processes, and its use can have positive environmental impacts due to its low embodied carbon. FTIR results show that the chemical composition of miscanthus surface changes in contact with all binders, with effects on the structures of both hemicellulose and lignin.
| Original language | English |
|---|---|
| Article number | 100053 |
| Journal | Cleaner Materials |
| Volume | 3 |
| Early online date | 7 Feb 2022 |
| DOIs | |
| Publication status | Published - 31 Mar 2022 |
Bibliographical note
Funding Information:This paper is part of an ongoing research at the University of Exeter, College of Engineering Mathematics and Physical Sciences, supported by a NERC GW4 + Doctoral Training Partnership studentship from the Natural Environment Research Council (NERC) and the National Productivity Investment Fund (NPIF) [NE/R011621/1]. Additional support and funding from CASE partners, Miscanthus Nursery and Agrikinetics Limited are also acknowledged. The authors wish to thank Prof. Oana Ghita of the Exeter Technology Group. The support from Dr Hong Chang with data acquisition on XRD and SEM is gratefully acknowledged. Dr Tommy Shyng is thanked for his assistance with TGA and FTIR measurements.
Funding
This paper is part of an ongoing research at the University of Exeter, College of Engineering Mathematics and Physical Sciences, supported by a NERC GW4 + Doctoral Training Partnership studentship from the Natural Environment Research Council (NERC) and the National Productivity Investment Fund (NPIF) [NE/R011621/1]. Additional support and funding from CASE partners, Miscanthus Nursery and Agrikinetics Limited are also acknowledged. The authors wish to thank Prof. Oana Ghita of the Exeter Technology Group. The support from Dr Hong Chang with data acquisition on XRD and SEM is gratefully acknowledged. Dr Tommy Shyng is thanked for his assistance with TGA and FTIR measurements.
Keywords
- Bio-based building materials
- Chemical interaction
- Interface morphology
- Lime
- Mineralogical transformation
- Miscanthus
ASJC Scopus subject areas
- Environmental Engineering
- Mechanics of Materials
- Waste Management and Disposal
- Polymers and Plastics