| Vegetation concrete ecological slope protection technology plays an important role in the ecological restoration of rock slopes.This technology achieves slope ecological restoration by spraying matrix,and the Super Absorbent Resin(SAR)is an important part of ecological matrix.In this paper,corn straw was used as raw material to prepare a new type of water-retaining agent by microwave polymerization,and then the new Super Absorbent Resin was applied to the ecological slope protection technology of vegetation concrete.The applicability of the new Super Absorbent Resin in the technology and the optimal ratio of spray sowing matrix were discussed.The main contents and results are as follows:(1)Development of new water retaining agent.Using corn straw as raw material,SAR was prepared by microwave polymerization.The L8(2~7)orthogonal experiment table was designed to analyze the influence of seven factors with the water absorbency of the Super Absorbent Resin in tap water as the objective.Four factors with greater influence were selected for the single factor optimization experiment.The infrared spectrum analysis was used to confirm that the graft copolymerization of straw cellulose and acrylic acid monomer was successful,and the polymerization became cellulose-based SAR.Finally,the optimal preparation conditions for microwave-assisted preparation of SAR were determined as follows:straw powder 100 mesh,neutralization degree 80%,graft monomer acrylic acid mass 8 g,the mass ratio of initiator to acrylic acid was 1.4%,the initiation time was 1.5min,the mass ratio of crosslinking agent to acrylic acid was 0.07%,the crosslinking time was 2.5 min.(2)Determination of basic properties of new Super Absorbent Resin.The basic properties of the new Super Absorbent Resin were determined.The results showed that the absorption capacity of distilled water was 785.8 g/g-1023.60 g/g,the absorption rate of tap water was 172.67 g/g-532.00 g/g,the absorption capacity of saline was 63.60 g/g,and the p H value was about 7.22.The experiment showed that the new Super Absorbent Resin had a rapid water absorption rate and could reach the liquid absorption equilibrium within 25 min.The repeated water absorption capacity,gel water retention performance and water retention performance after adding soil were good.(3)Discussion on the applicability of new water retaining agent in the greening technology of bare rock slope.The effects of the proportion of Super Absorbent Resin content,the water absorption rate of Super Absorbent Resin,and the cement content and p H regulator on the greening matrix of vegetation concrete were compared.The pot experiment was carried out by using the L9(3~4)orthogonal experiment table.The physical properties and plant growth status of the experimental sample and the control sample were measured and analyzed,indicating that the prepared new water retaining agent was suitable for the greening of bare rock slope.(4)Range analysis was carried out on the physical properties and plant growth data measured in the application experiment of new water retaining agent in bare rock slope.The proportion of water retaining agent and cement content had significant effects on the physical properties and plant growth in the matrix,while the water absorbency of water retaining agent had little effect on it.p H regulator could improve the alkaline environment in the matrix and indirectly affect the plant growth.Comprehensive analysis showed that the optimum range of matrix ratio-water retention agent was:the Super Absorbent Resin accounted for 0.15%,water absorption rate was medium,cement accounted for 5%,p H regulator accounted for 15%,matrix ratio was better. |
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