Study On The Preparation Of Portland Cement Plant-foamed Concrete And Its Plant-growth Properties

In recent years,with the vigorous promotion of the national sponge city construction policy,the construction of sponge city based on the concept of ecological architecture is gradually known to people.In people’s continuous exploration of the goal of harmonious coexistence of city and nature,roof greening is rapidly popular with its innate advantages,and has achieved the ecological needs of many cities in practice.In order to further promote the application of three-dimensional greening in roofing engineering,this thesis studies a planting raw foamed concrete material.With "greening+storage and drainage" as the main function under the new low impact development(LID)model,the existing planting module technology is improved to make it widely used in the society.Therefore,this thesis focuses on studying the influence of the composition and mixing amount of foamed concrete on its performance,and gives full play to its good planting ability to prepare foamed concrete roof greening planting module with stable performance.In this thesis,the mix ratio of plant-grown foamed concrete was designed,and the variation rule of fly ash,water-binder ratio,foaming agent and SAP particles on the performance of plant-grown foamed concrete was studied in the test.With orthogonal experiment research of various factors on the pH,bulk density,porosity,water absorption and the influence of flux,by Z value of comprehensive evaluation method and comprehensive balance method,determines the optimization of preparation of vegetation type of foam concrete mixture ratio,namely the water-binder ratio 0.35,40%dosage of fly ash,dosage of foaming agent was 8.0%,the dosage of SAP particles was 0.35%.On the basis of the above experimental data,the author discusses the negative correlation between the water permeability and water storage of the plant-foamed concrete to a certain extent,that is,when the water absorption of the plant-foamed concrete increases,the water permeability tends to decrease,showing a negative correlation between the two.In this thesis,the reasonable technology of preparing surface substrate and planting foamed concrete is put forward.Sap particles with pre-absorbed alkali-reducing solution were mixed into the foamed concrete as water and fertilizer preserving material,and plant-growing foamed concrete was prepared by adjusting the internal supporting environment.The plant growth experiment of plant growth foam concrete showed that the germination rate reached 60%after curing with reducing-alkali nutrient solution,and the plant growth height reached 14.66cm after 27 days,which was higher than the germination rate and plant height after curing with tap water,and the growth state was good.The plant was in the plant foamed concrete with alkali reducing nutrient solution,and the root system could extend into the concrete in two weeks.The root system had good ductility to the plant foamed concrete.It can be seen that planting foamed concrete prepared by optimal mix ratio has stable planting energy.Plant foamed concrete planting module is divided into three parts in this thesis:plant layer,structure beam layer and side plate.The water layer of the structure beam provides load support for the plant layer.Calcium stearate is added for hydrophobic modification treatment to reduce the water permeability of the foamed concrete.At the same time,a diversion groove is added at the bottom of the side plate to ensure that excess water is discharged along the design path under the condition of heavy precipitation.The freezing and thawing cycle tests were carried out on the foamed concrete in the plant layer and the structure water bundle layer of the planting module.The results show that the frost resistance of the plant foam concrete can be improved by introducing appropriate amount of SAP particles into the plant layer and hydrophobic agent into the structure water bundle layer.