Performance Analysis And Benefit Evaluation Of New Materials Artificial Reef

Artificial reefs are a basic project for the construction of marine ranching,with functions such as marine ecological regulation,marine habitat restoration and proliferation of fishery resources.Since the 1950s,The global coastal countries have successively used artificial reefs as an important measure for the conservation of fishery resources.Construction of artificial reefs has begun,and a series of studies have been carried out on the materials,structure and layout of artificial reefs.In recent years,Chinese scholars'research on artificial reefs has begun to extend toward the addition of reef concrete materials.The main research content of this paper has three aspects:1).On the basis of the ordinary concrete mix ratio of compressive strength C25,the coarse and fine scallop shells were used to replace the natural aggregate in the concrete,and the scallop shell concrete mix ratio test was carried out to compare the coarse and fine scallop shells to replace the natural ones,working properties and basic mechanical properties of aggregate concrete.2).Based on the ordinary concrete mix ratio of compressive strength C25,the effects of different blending ratios of wheat straw powder on the work performance and basic mechanical properties of concrete were studied.3).Based on the ordinary concrete mix ratio of compressive strength C25,the effects of different replacement ratios of cement ash on concrete performance and compressive strength of concrete were studied.4).According to the reef plan of Shandong Province from 2016 to 2020,it is possible to estimate the carbon sequestration potential of natural aggregates in the artificial reef concrete by using bay scallop shells,the land area of cleanable abandoned bay scallop shells and the cost of building reef materials;It is possible to estimate the carbon sequestration potential of artificial reef concrete mixed with wheat straw powder;It can be estimated that replacing cement in artificial reef concrete with fly ash can save the cost of reef-building materials.The main findings are as follows:(1).The compressive strength of concrete with Argopecten irradias shells to replace part of the aggregate can reach the artificial reef construction standard and can be used for artificial reef construction.As the proportion of scallop shells replacing natural aggregates increases,the workability of concrete decreases,and the compressive strength first increases and then decreases.The best replacement rate for scallop shells as a substitute for natural stone is 40%,and the best replacement rate for fine sand as a substitute for natural sand is 60%.Comparing the experimental results,it can be seen that the concrete performance of the scallop shell as a substitute for fine aggregate is better than that of the scallop shell as a coarse aggregate.The replacement rate of concrete natural fine aggregates with fine scallop shells is estimated to be 50%to 70%.For example,the planned new construction of 20.43 million square artificial reefs in Shandong Province from 2016 to 2020 is made of this concrete,which can realize the carbon sequestration of the reef from 275400 to 385,600 tons,which can reduce the land area of abandoned shells by 5.89 to 8.2 km~2,and the construction unit of the artificial artificial reef can save 10.36 to 14.50 yuan,which can save the cost of building reef concrete materials.2.3×10~4~3×10.~4 million.Has a high ecological potential and economic potential.(2).Through the study on the properties of concrete with a small amount of wheat straw powder,it is found that with the increase of the proportion of wheat straw powder,the slump of fresh concrete and the compressive strength of concrete at different ages are decreasing.When the wheat straw powder blending ratio is less than 6%of the cement quality,the fresh concrete can ensure good working performance,and after the standard curing period,the compressive strength can reach above C20,and the strength requirements for the preparation of artificial reefs have been met.In the actual production process,the water consumption can be appropriately increased to improve work performance and pressure resistance.Estimated by the ratio of wheat straw powder to 2%,4%,and 6%.If the planned new construction of 20.43 million square artificial reefs in Shandong Province from 2016 to 2020 is made of this concrete,which can realize the carbon fixation of the reef from 27.54 to 385,600 tons.(3).The replacement of some cement concrete with fly ash has improved the workability of fresh concrete.As the proportion of fly ash replacing cement increases,the early compressive strength of concrete shows a decreasing trend compared with the reference concrete.However,after curing to 60 days,the compressive strength of concrete is higher than that of the reference concrete.That is to say,the early compressive strength loss caused by the replacement of fly ash can be compensated back later with the increase of the number of curing days.When the replacement rate of fly ash is 10%to 40%,the compressive strength of concrete 28d reaches above C20,which meets the strength requirements of artificial reef construction..Taking the reef-building plan of Shandong Province from 2016 to 2020 as an example,if the artificial reef is constructed by using fly ash instead of some concrete,the construction of the artificial artificial reef can save about 2.97~11.89 yuan,which can save the total reef.The cost is about 7×10~3~2.8×1.0~4 million.