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CN-121974638-A - Nutritional dredging sediment modified carbon-fixing ecological concrete and preparation method thereof

CN121974638ACN 121974638 ACN121974638 ACN 121974638ACN-121974638-A

Abstract

The invention discloses a carbon-fixing ecological concrete modified by nutrient dredging sediment and a preparation method thereof, wherein the carbon-fixing ecological concrete comprises, by weight, 180-200 parts of coarse aggregate, 70-90 parts of cementing material, 10-15 parts of nutrient modified dredging sediment, 28-32 parts of water and 3-6 parts of polycarboxylate water reducer, and the preparation method of the nutrient modified dredging sediment is to soak the dried dredging sediment in a compound modification solution, wherein the compound modification solution consists of 80-100g/L of diammonium phosphate solution and 0.2-0.5% of chitosan solution. According to the invention, the dredging sediment is subjected to nutritional modification treatment by the composite modification solution, and then the carbon-fixing ecological concrete is prepared, so that the compressive strength, the supporting performance and the activation effect on carbon-fixing functional microorganisms are improved, and the high-value recycling of wastes is realized.

Inventors

  • ZENG HUI
  • YANG JIN
  • WEI XIAOXIANG
  • YU FENG
  • GUO GUANGHUI
  • ZHANG CHI
  • CHU HONGQIANG

Assignees

  • 中国长江电力股份有限公司

Dates

Publication Date
20260505
Application Date
20260115

Claims (10)

  1. 1. The carbon-fixing ecological concrete modified by the nutrient dredging sediment is characterized by comprising, by weight, 180-200 parts of coarse aggregate, 70-90 parts of cementing materials, 10-15 parts of nutrient modified dredging sediment, 28-32 parts of water and 3-6 parts of polycarboxylate water reducer.
  2. 2. The nutrient dredging sediment modified carbon-fixing ecological concrete according to claim 1, wherein the nutrient modified dredging sediment is obtained by treating the dredging sediment with a composite modifying solution.
  3. 3. The nutrient dredging substrate sludge modified carbon-fixing ecological concrete as claimed in claim 2, wherein the composite modification solution consists of a diammonium phosphate solution and a chitosan solution.
  4. 4. The carbon-fixing ecological concrete modified by the nutrient dredging sediment according to claim 3, wherein the concentration of the diammonium phosphate solution is 80-100g/L, and the concentration of the chitosan solution is 0.2-0.5%.
  5. 5. The nutrient dredging sediment modified carbon-fixing ecological concrete of claim 2, wherein the dredging sediment is derived from water sediments such as river channels, lakes, reservoirs and the like, and the water content is less than or equal to 20%.
  6. 6. The carbon-fixing ecological concrete modified by the nutrient dredging sediment according to claim 1, wherein the cementing material consists of silica fume and sulphoaluminate cement according to the mass ratio of (1-2) to 20.
  7. 7. The nutrient dredging substrate sludge modified carbon-fixing ecological concrete as claimed in claim 1, wherein the coarse aggregate is gravel and has a particle size of 20-30mm.
  8. 8. A method for preparing the nutritional dredging sediment modified carbon-fixing ecological concrete according to any one of claims 1 to 7, which is characterized by comprising the following steps: (1) Taking dredging sediment, drying, then putting the dredging sediment into a composite modifying solution, soaking for modification, and then washing and drying to obtain nutritionally modified dredging sediment; (2) Uniformly mixing dredging bottom mud with a cementing material, a polycarboxylate water reducer and water to obtain a first mixture; (3) Adding coarse aggregate into the first mixture, and uniformly mixing to obtain a second mixture; (4) And (3) placing the second mixture into a mould for molding, and curing to obtain the carbon-fixing ecological concrete.
  9. 9. The method of claim 8, wherein the soaking modification conditions in the step (1) are soaking reaction at room temperature for 24-36 hours.
  10. 10. The method of claim 8, wherein the curing conditions in the step (4) are curing for 25-30 days at 18-22 ℃ with a relative humidity of 95% or more.

Description

Nutritional dredging sediment modified carbon-fixing ecological concrete and preparation method thereof Technical Field The invention belongs to the technical field of ecological concrete, and in particular relates to carbon-fixing ecological concrete modified by nutrient dredging sediment and a preparation method thereof. Background Ecological concrete is regarded as a potential solution to cope with carbon emissions and ecological degradation as a green building material due to its sustainability and versatility. On one hand, the plant-based carbon-fixation composite material can partially replace the traditional cement component, reduce energy consumption and CO 2 emission, and on the other hand, the plant-based carbon-fixation composite material can absorb CO 2 through photosynthesis to realize a double carbon fixation path of 'source control and sink suction'. However, the existing ecological concrete has the technical bottlenecks that (1) due to higher porosity and insufficient overall mechanical strength of the material, the application of the ecological concrete in bearing engineering is limited, (2) key nutrient elements such as nitrogen and phosphorus required by plant growth are often lacking in a matrix, the effect of planting is limited, and (3) related researches only focus on macroscopic mechanical properties and plant-growing properties, and a functional microbial system with important effect on promoting carbon conversion is omitted. Conventional dredging operations of bodies of water in river, lake, reservoir, etc., produce sediment deposits of over 6 hundred million cubic meters each year worldwide. The traditional bottom mud disposal mode such as stacking, landfill or returning to the field or forests occupies land resources. In addition, the river and lake dredging sediment is enriched with various pollutants such as heavy metals, nitrogen and phosphorus nutrient salts, POPs and the like, and the direct digestion treatment is easy to cause secondary pollution to the ecological environment, so that the dredging sediment is required to be subjected to harmless treatment. The conventional method realizes passivation, degradation and removal of pollutants in the processes of curing treatment, biostabilization treatment, repair treatment and the like, so that Cao Zheng secondary pollution is avoided, and convenience is provided for subsequent safe recycling. For example, wang and the like adopt cement and silicon-rich minerals to carry out solidification treatment on the dredging sediment, so that heavy metals can be effectively sealed and stored, the mechanical strength （WANG L, CHEN L, CHO D W, et al. Novel synergy of Si-rich minerals and reactive MgO for stabilization/solidification of contaminated sediment[J]. Journal of Hazardous Materials, 2019,365:695-706.）, of the sediment is improved, and finally the application requirements of filling materials in engineering can be met. However, the risk of secondary leaching exists, and the recycling application value of the product is low. Lv Zhigang and the like, uniformly mixing river and lake dredging substrate sludge with auxiliary materials such as waste mushroom residues, sawdust, pig manure, rice hulls and the like according to a proper proportion, and piling up for 30 days, wherein the obtained auxiliary products are in a brown-black humus shape, loose in structure, free of odor, naturally reduced in temperature and moisture, and the germination index of seeds is more than 60%, the cost is low, but the treatment period is long, a large area of land is still required, and the application value of the product is not high (Lv Zhigang, yang Yanli, xu Min. The river and lake dredging substrate sludge and solid waste aerobic composting research [ J ]. Environmental science and technology, 2010,23 (2): 12-14.). Chinese patent CN114455903A discloses ecological concrete for river pollution restoration and a preparation method thereof, wherein the ecological concrete is prepared by using river sediment, gel material, water reducing agent, foaming agent and nano manganese dioxide, the compressive strength of the concrete is improved by using the catalytic property of the nano manganese dioxide, the removal efficiency of heavy metals and organic matters is improved, and finally the concrete is strengthenedPlants and methods of making the sameAdsorption properties of microbial systems to contaminants. However, the adopted nano manganese dioxide has high cost, and is easy to generate agglomeration phenomenon, so that the catalytic activity of the nano manganese dioxide can be reduced, and the micro structure in the concrete can be uneven, so that the mechanical property and durability are affected. Therefore, there is a need to develop a method for preparing ecological concrete by using dredging sludge with low cost and high efficiency so as to improve the utilization value of the dredging sludge. Disclosure of Invention Aiming at the technical proble