Sustainable Wall Solutions Using Foam Concrete and Hemp Composites

Abstract

This work is devoted to developing an energy-efficient solution for the external wall and evaluating its environmental impact. Several types of innovative single-layer and sandwich-type wall solutions were analysed and compared. Different constructive and thermal insulation materials were used, including traditional wall materials such as AAC (autoclaved aerated concrete) and normal concrete. Advanced materials, such as high-performance foamed concrete (HPFC) and natural biofibre composites, have been evaluated as an alternative solution. Ultra-light foam concrete was applied as an alternative for polymer-based insulation. The next development was sandwich three-layer wall constructions consisting of foam concrete and natural biofibre composites. A prototype of a wall panel was elaborated with outer layers of high-density bio-composite and a middle layer of high porosity hemp composite. Basic properties of sandwich blocks, such as density and thermal conductivity, were evaluated and compared. The environmental impact of the studied wall systems was analysed using a life-cycle assessment (LCA) to assess carbon dioxide emissions during the production phase of the material. The results show that replacing traditional insulation with bio-based materials has greatly reduced the negative environmental impact of the wall elements. A combination of natural fibre bio-composite and mineral insulating foam makes it possible to obtain an eco-friendly and sustainable sandwich-type wall system.

Production Technology of Ecological High Performance Fibre Composite Construction Materials

“…The most CO2-neutral material is hemp concrete, composed of hemp shives, as a filler and lime binder. Following previous analysis [1,2], such compositions have a negative balance of carbon dioxide emission. The disadvantage of hemp-lime concrete is its low mechanical strength (< 0.5 MPa compressive strength) [3].…”

“…Regarding the context of GWP (global warming potential), it was emphasized that the bio-based 3layer panel has the largest advantage, as hemp shives absorb CO2 in the growing process and low amounts of the binder are used for the board, thus having 6 times lower emissions than traditional materials -only 12.7 kg/CO2 eq. per 1 m 2 of panel [2].…”

Hempcrete – CO2 Neutral Wall Solutions for 3D Printing

“…Impact for 1 m 2 of the wall with the defined U-value is calculated using 'cradle-to-gate' system boundaries. For comparison with the traditionally used materials, previous studies have been used, where walls with brick blocks and polystyrene layer [20], aerated concrete and insulated reinforced concrete [13], various insulated masonry block constructions [21] have been used.…”

“…Similarly, high values of 107.88 kg of CO2 eq. are obtained in a study comparing several hempcrete construction types and a traditionally built wall of a 300 mm brick block and a 120 mm polystyrene insulation layer [20]. Using hemp blocks, a wall with the same thermal transmittance produces 44 kg of CO2 eq., which is explained in the study by the high negative impact of the used binder -hydraulic lime [19].…”

Experimental investigation of heat transfer in bio-based building block with microencapsulated PCM

“…The use of such materials is really important in the building industry to reduce the impact of this market on the environment in different fields. Bio-based materials to be applied in the building industry can contain various fillers, e.g., bamboo [1], coconut [2], cellulose [3], cassava starch [4], and hemp shives [5][6][7]. The application of hemp shives appears potently attractive concerning the use of waste from fiber-using industries like textile one [8].…”