Planting And Electrothermal Properties Of Carbon Fiber-Graphite Electrothermal Ecological Substrate

The concept of electrothermal ecological substrate is proposed on the basis of traditional ecological substrate.By adding conductive phase materials,the traditional ecological substrate can be conductive and heating.In order to obtain the plant property,electric heating property and mechanical property,so as to estimate the practical application of electrothermal ecological substrate.This thesis mainly includes pot planting experiment,electrothermal experiment and unconfined compressive strength-resistivity test.The specific work is as follows:(1)Through the orthogonal experiment method,16 groups of different proportions of electrothermal ecological substrate are designed to carry out pot experiment.The data of germination rate,growth height and area coverage rate are monitored during planting process,and the effects of cement,polystyrene(EPS),carbon fiber and graphite powder on plant growth are compared.The optimal ratio for zoysia grass growth is 4% EPS,2.5% cement,1% carbon fiber and 10% graphite powder.(2)Through the electrothermal test,the resistivity of the electrothermal ecological substrate specimens at different ages are measured and the heating efficiency in unit time is studied.The variation of the thermal sensitivity during heating is revealed.The results show that the electrical conductivity of the substrate is stable after long curing.Rootless substrate resistance increases first and then decreases due to electron transfer and moisture evaporation.However,due to the absorption of water by the root system,the resistance of the substrate with root continues to increase,resulting in a decrease in the peak temperature.But below 40?,the heating rate is nearly the same.(3)The unconfined compressive strength-resistivity test is carried out to detect the resistivity variation of electrothermal ecological substrate under external load deformation.As a result,the compressive strength and resistivity of the substrate decrease with the increase of water content.With the development of the dry-wet cycles,the compressive strength of the substrate decreases,and the resistivity of the substrate increases,which means the electrical conductivity decreases.After the first wet-dry cycle,the specimens begin to crack,the compressive strength of the substrate decreased significantly,and the resistivity of the substrate increased.However,with the further development of the wet-dry cycles,more and more cracks are found in the specimens,resulting in higher resistivity and stable compressive strength.The invention of electrothermal substrates has broken through the concepts of ordinary ecological substrates,and makes up for the shortcomings of ordinary ecological substrates in the face of severe cold conditions.This will be one of the future development trends of ecological substrates.