Performance Test And Comprehensive Benefit Analysis Of 3D Printing Concrete For Marine Prefabricated Components

Compared to traditional construction techniques,3D printed concrete technology has freed itself from the constraints of traditional construction templates,achieving the goals of complex and variable shapes,high production efficiency,significantly reducing construction costs,and saving resources and labor.Marine prefabricated components are an important component of marine engineering construction,but the construction process of marine prefabricated components has problems such as low technological content and excessive resource consumption,which are easily constrained by construction conditions and social resources.It is urgent to transform and upgrade to meet the growing demand.The development of 3D printed concrete technology has provided an opportunity for the transformation of prefabricated components in marine engineering to digital intelligence,but so far,the application of3 D printed concrete technology in marine engineering is relatively limited.This article explores the comprehensive benefits of 3D printed concrete technology in the field of marine prefabrication by studying its technical feasibility,economic feasibility,and low-carbon environmental friendliness.The main work is as follows:(1)Through physical experiments,a comparative analysis was conducted on the mechanical anisotropy of 3D printed concrete specimens under three different printing paths.The results showed that under different printing paths,the compressive strength varied,but all met the design requirement of 35 MPa,and the compressive strength in three directions was the highest under concentric circular paths;A comparative analysis was conducted on the compressive strength of printed test blocks using staggered paths under different curing conditions.The results showed that the compressive strength of the test blocks increased with the increase of curing age.When the curing age was the same,the maximum difference in compressive strength between seawater curing and freshwater curing in three directions was 3.9%,indicating that there was no significant difference between seawater curing and freshwater curing;Numerical simulation was conducted using PFC discrete element software on test blocks with parallel and concentric printing paths.From a microscopic perspective,the failure morphology and crack distribution of 3D printed concrete test blocks in the X and Y directions were analyzed.Compared with physical experiments,the fit was good,confirming that the expansion of cracks in 3D printed concrete specimens is directly related to interlayer weak surfaces,and the development of cracks is related to the extension direction of weak surfaces;(2)The 3D printed concrete specimens with the same mix ratio were subjected to freeze-thaw cycle tests,sulfate resistance tests,and p H change tests after soaking in seawater under different curing conditions.The results showed that the mass loss rate of the 3D printed concrete specimens was 0.1%,much lower than the design requirement of 5%,and the frost resistance performance met the requirements;The ability to resist sulfate attack needs to be improved;After the completion of two curing methods for 3D printed concrete specimens,the p H value of the specimens soaked in seawater showed a trend of first increasing and then decreasing with the growth of the specimens,and tended towards the control group.The change in p H value of the specimens cured with seawater was smaller than that cured with fresh water;(3)Taking the 3D printing concrete technology for prefabricating abalone reefs and wave dissipation blocks as an example,a specific construction plan for 3D printing prefabrication blocks was developed,and the engineering cost was calculated.The results show that compared with traditional construction methods,the 3D printing concrete construction method has undergone changes in labor,cost structure,and construction period.Among them,the 3D printing prefabrication technology has saved 12.21% and 7.6% in construction costs,and the project progress has been shortened by 26% and 22.4%,respectively;(4)Taking the prefabricated abalone reef of marine ranch as an example,based on the physical and chemical stage,the physical and chemical stage Carbon footprint is divided into three aspects: materials,construction and transportation,and the carbon emissions from conventional prefabricated abalone reef and 3D printed concrete technology prefabricated abalone reef are quantitatively compared and analyzed.The results show that the carbon emissions from 3D printed concrete prefabrication technology reduce 4566083.267 kg CO2eq compared with conventional prefabricated abalone reef,Only 71.08% of traditional prefabrication methods.