Energy-Efficient Natural Fiber Biocomposites with Reduced Environmental Impact and Their Applications
Māris Šinka

02.11.2018. 14:00, RTU BIF, Ķīpsalas iela 6A, RĪga

Genādijs Šahmenko

Juris Smirnovs, Sigitas Vejelis, Paulien Strandberg-De Bruijn

Within the framework of the doctoral thesis, solutions for reducing the environmental impact of the construction materials industry were sought, in particular how to reduce the amount of greenhouse gases in the atmosphere. One of the solutions would be using energy-efficient natural fiber biocomposites, due to their low thermal conductivity and environmental impact, but their low strength and longevity properties prevent them from being widely used. Therefore, the objective of the doctoral thesis was to develop an energy-efficient natural fiber biocomposites with improved mechanical, physical and durability properties, as well as reduced environmental impact. In order to achieve this objective, lime and magnesium binders for biocomposites using waste products as active additives to minimize the environmental impact of the binder have been developed. Three types of binders have been chosen for the further research - formulated lime binder with a metakaolin additive reaching at least 10 MPa strength and two types of magnesium binders - magnesium oxychloride cement and magnesium phosphate cement with a strength over 50 MPa. Using selected binders and natural fiber aggreagates - hemp shives - biocomposites were developed and the influence of various factors on their mechanical, physical properties of biodegradability and reaction to fire has been studied. Using fast curing magnesium binders, biocomposites can reach the necessary strength at low density and thermal conductivity conditions - around 200 kg/m3 and 0.062 W/m·K. Compared to the conventional building materials containing bio-based aggregates, biocomposites have a low fire reaction - class B according to LVS EN 13501 – and equally high biodegradability. Within the framework of the doctoral thesis, natural fiber biocomposites have been studied under field conditions using a specially designed measuring system consisting of temperature, relative humidity and heat flow sensors, simultaneously measuring the distribution of moisture and temperature in the wall thickness, as well as the heat resistance of the wall. A specially developed method for calculating U values for dynamic heat flows had been used. The developed method for the life cycle allows the use of experimental results of the thermal conductivity and strength of biocomposites to create a model for assessing the environmental impact of natural fiber biocomposite functional units and compare them with conventional building materials. By comparing the environmental effects of lime-based binder, it can be concluded that the hydrated lime binder with metakaolin (FHL) for all factors have 12 % -55 % lower effect than a commercial hydraulic lime binder. Magnesium binder biocomposites, such as MOC, give a significantly lower environmental impact than MPC, despite the high strength and density ratio of MPC associated with its hardener - potassium phosphate, which is highly energy and resource-intensive. Compared to other materials, natural fiber biocomposites show 2-4 times lower emissions and are the only CO2 neutral materials that demonstrate their reduced environmental impact.

Biokompozīti, CO2, Dzīves cikla analīze, DCA, LCA, kaņepju betons

Šinka, Māris. Energy-Efficient Natural Fiber Biocomposites with Reduced Environmental Impact and Their Applications. PhD Thesis. Rīga: [RTU], 2018. 121 p.

Publication language
Latvian (lv)
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