Study On Marine Concrete By Response Surface Methodology And Mathematical Statistics Method

Based on the actual condition of a port in Dandong,the paper makes an optimization study on mix proportion of marine concrete.Firstly,the response surface method is used to analyze the characteristics of marine concrete mixture by using Design-Expert8.0 software,such as slump,slump flow and loses through time.Then,hundreds of test groups of marine concrete with different strength grades were provided by construction units,and the relationship between strength and rebound values are statistically analyzed by MATLAB software to establish the strength curve of marine concrete for different projects.Finally,the frost resistance test is carried out on some specimens.The main research results show that:(1)The model of the loss through time of marine concrete mixture is established through the 18 groups of concrete mixture consistency test,and the influence order of the three main parameters on concrete mixtures and the interactive relationship of the three parameters is determined(water-binder ratio> Sand ratio>replacement rate of fly ash and mineral powder).Finally,the range of concrete parameters about the loss through time within 10% is given;(2)Using the curve fitting toolbox in MATLAB to established the special strength curve about the compressive strength and the rebound value of the marine concrete,which is suitable for the engineering condition,is established considering carbonization depth or not,and analyzed the effect of carbonization on measurement curve,and it is recommended to use the surface function to establish a special strength curve;(3)300 times rapid freeze-thaw cycle test shows that,the mass loss and dynamic modulus loss of the nine specimens,and the durability coefficient can reach the design requirements of 100 years.After the freeze-thaw cycles,the specimens meet the design requirements that both compressive strength and bending strength;(4)But much loss in compressive strength beyond mass loss and dynamic modulus loss,and it is recommended in the marine concrete design to add the requirements of strength loss after freeze-thaw cycles.Finally,the influence degree of three factors on the durability of marine concrete is given: water-binder ratio>sand ratio>proportion of fly ash and mineral powder.