Part Of The Degradation Of Spraying On The Consolidation Of Composite Materials

The harm to environment from yellow river originates from sediment.The key to soil and water conservation is sediment regulation of its coming area.Radical reform must be performed to form good vegetation in the sediment coming area based of keeping water,soil and fertilizer.Sediment regulation and vegetation of the sediment coming area in the middle yellow river has a great importance for water and soil loss comprehensive harness of yellow river.Under the support of National Natural Science Foundation,this paper aims at batching new type partial degradable spraying cementitious material which can consolidate sediment and promote plant growth.The final purpose is to forming mutual alternation between bonding layer and vegetation systems for soil water conservation.From the research of experiment,some original conclusions are as follows:(1) Three sets network system had been designed which lay a foundation of design and preparation of partial degradable spraying eementitious material. Three sets network system are composed of cenmentious materials,organic function component and plant fiber system.A Cenmentious material which is high w/c ratio Micro-expanding Cement can supply the main strength structure.Organic function component which is water soluble Biodegradable Material can improve toughness, water absorption,water conserving function and provide water and fertilizer by means of later slow degradation.Plant fiber can arrest crack and provide water and fertilizer by means of later slow degradation too.Three sets network system have different strength,toughness and durability and interact to form partial degradable spraying cementitious material.(2) This paper optimized the material of three sets network,determined the mix ratio of partial degradable spraying cementitious material.Moreover,the mechanical properties influence of component materials is discussed.The results show that:In order to meet the requirements of strength and slight expansion,the optimal proportion of inorganic gelling material is 20%cement,10%aluminate cement,40%fly ash,13%red mud,10%dihydrate gypsum,6%lime,1%Activator. Polyacrylamide increase workability and toughness.Corn starch as water absorbent material can improve water absorption and conservation properties and improve water condition because it can prevent water from evaporating.Plant fiber can improve toughness and crack resistance of cement-based material.By above research,the optimal proportion is 94.5%cement,0.5%Polyacrylamide,4.0%Corn starch,1.0% plant fiber.(3) Microstructure and mechanism of partial degradable spraying cementitious material had been deeply researched.The results show that:Under natural conditions,polyacrylamide can form the net in the cement hydration,because they can form special chemical bond with cement hydrate which can improve the physical structure of the material,and increase toughness and decrease the brittleness of cement-based material.Plant fiber can form three-dimensional network,and it can improve toughness and crack resistance of cement-based material.Because of plant fiber elastic modulus is higher than plastic cement hydration and fiber diameter is fine, although larger gas content of paste leads to the strength decreases leading because of large specific surface area.(4) Strength-degradation regularity of partial degradable spraying cementitious material was studied in order to research Degradation Mechanism. It shows that:Mechanical properties begin to decrease after 28-days treatment under natural conditions.Mass and strength loss is obvious under accelerated aging treatment.After six times dry-wet Cycles,mass loss is up to 6%,strength loss is up to 52.5%,and residual strength is 3.8MPa.After six times freeze-thaw cycles,mass loss is up to 4.3%,strength loss is up to 46%,residual strength is 2.9MPa.It can be meet the requirements of soil Consolidation on prophase and degradation on anaphase.(5) The study on partial degradable spraying cementitious material shows that:Designated structure,controllable strength development and partial degradable spraying cementitious material in-depth study will come ture by there sets network system interaction.Partial degradable spraying cementitious material has high theoretical research value and good application fore ground and will be widely used in sediment regulation and vegetation restoration.