Microstructural Characterization of Prefabricated Hempcrete Blocks

Author(s):  
Chiara Moletti ◽  
Valeria Arosio ◽  
Giovanni Dotelli

Sustainable building materials have been developed to reduce the polluting emissions and the exploitation of natural resources of the building sector. Among these materials, an outstanding category is that of nature-based solutions which are produced recovering waste or by-products of agricultural cultivations and using them as vegetal aggregates to replace the traditional ones. This paper focusses on hempcrete which is produced mixing the by-product of industrial hemp cultivation (i.e., shives) and lime to obtain a sustainable, breathable and insulating material. The strength of hempcrete develops through carbonation of the binder that, leading to the formation of calcium or magnesium carbonates and mineralization of shives, determines the microstructure and hence most of the characteristic properties of the material. The aim of this research is to investigate how carbonation influences the microstructure of hempcrete when different recipes are used for blocks production. This study consists in the characterization of the material through techniques such as XRD (X-ray Diffractometry), SEM (Scanning Electron Microscopy) and TG-DTG (thermogravimetric analyses). Moreover, the evolution of carbonation is studied analyzing samples at different maturation times. The investigation of the carbonation reaction degree is also crucial to evaluate the environmental performances of the material because it allows the quantification of the carbon dioxide uptake. Also, periodic characterization allows to assess the durability of hempcrete and to select the best formulation according to the designed application and the corresponding service conditions.

2020 ◽  
Vol 10 (11) ◽  
pp. 4032
Author(s):  
Anna-Marie Lauermannová ◽  
Michal Lojka ◽  
Filip Antončík ◽  
David Sedmidubský ◽  
Milena Pavlíková ◽  
...  

The search for environmentally sustainable building materials is currently experiencing significant expansion. It is increasingly important to find new materials or reintroduce those that have been set aside to find a good replacement for Portland cement, which is widely used despite being environmentally insufficient and energy-intensive. Magnesium oxybromides, analogues to well-known magnesium oxychloride cements, fit both categories of new and reintroduced materials. In this contribution, two magnesium oxybromide phases were prepared and thoroughly analyzed. The stoichiometries of the prepared phases were 5Mg(OH)2∙MgBr2∙8H2O and 3Mg(OH)2∙MgBr2∙8H2O. The phase analysis was determined using X-ray diffraction. The morphology was analyzed with scanning and transmission electron microscopy. The chemical composition was studied using X-ray fluorescence and energy dispersive spectroscopy. Fourier transform infrared spectroscopy was also used. The thermal stability and the mechanism of the release of gasses linked to the heating process, such as water and hydrobromic acid evaporation, were analyzed using simultaneous thermal analysis combined with mass spectroscopy. The obtained results were compared with the data available for magnesium oxychlorides.


2018 ◽  
Author(s):  
Neeti Garg ◽  
Ashwani Kumar ◽  
Satish Pipralia ◽  
Parveen Kumar

Buildings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 64 ◽  
Author(s):  
Hanaa Dahy

Choosing building materials is usually the stage that follows design in the architectural design process, and is rarely used as a main input and driver for the design of the whole building’s geometries or structures. As an approach to have control over the environmental impact of the applied building materials and their after-use scenarios, an approach has been initiated by the author through a series of research studies, architectural built prototypes, and green material developments. This paper illustrates how sustainable building materials can be a main input in the design process, and how digital fabrication technologies can enable variable controlling strategies over the green materials’ properties, enabling adjustable innovative building spaces with new architectural typologies, aesthetic values, and controlled martial life cycles. Through this, a new type of design philosophy by means of applying sustainable building materials with closed life cycles is created. In this paper, three case studies of research pavilions are illustrated. The pavilions were prefabricated and constructed from newly developed sustainable building materials. The applied materials varied between structural and non-structural building materials, where each had a controlled end-of-life scenario. The application of the bio-based building materials was set as an initial design phase, and the architects here participated within two disciplines: once as designers, and additionally as green building material developers. In all three case studies, Design for Deconstruction (DfD) strategies were applied in different manners, encouraging architects to further follow such suggested approaches.


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