Data Mining And Database Development Of Concrete Strength Evolution Under Marine Environment

In fierce circumstances,especially the marine environment,the degradation of concrete materials is becoming an increasing serious issue.And it is the coupling effects between various factors that contributes to this problem.Currently,large amounts of research,either in the laboratory or at the sea,has been carried out on this topic.And the laboratory experiments are usually completed through simulating the actual marine environment.It could be found that the influencing factors are complex and various.Simultaneous,concrete materials itself is complicated.This research are mainly focused on the compressive strength of concrete served in marine environment.Firstly,an overall review of the current research works was carried out.Influencing factors to compressive strength of marine environment concrete were extracted from literatures.The data of compressive strength of concrete and influencing factors were obtained.While those data were raw data,which need to be further dealt with.Clustering analysis,regression analysis and some other mathematic methods were used to handle those harsh data.Besides,knowledge on concrete were also been used.On the basis of those processed data,correlation analysis between the compressive strength and influencing factors had been done,including Pearson correlation analysis,Grey Relational Analysis(GRA)and Principle Component Analysis(PCA).And principle influencing factors were concluded from those analysis.Finally,a data base of compressive strength of concrete served in marine environment was established through SQL Server 2012.Comprehensive literatures collected is the basis and prerequisite of data collection.In this research,literatures are based on authoritative data base and Scirus at home and aboard.CKNI and WangFang Database were used to search for Chinese literatures while Web of Science and Elsevier were used to look through foreign literatures.Simultaneously,Google Scholar and Baidu Scholar were used to replenish the database.Finally,the material factors involved in the study were determined as follows: water cement ratio,cement type,cement strength,sand rate,specimen size,initial strength at 28 d,mineral admixture content;environmental factors: ion concentration,Circulation system and exposure age.The mineral admixtures include fly ash,slag and silica fume.The wet-dry circulation system includes the drying time,wetting time,drying temperature,wetting temperature and the cycle of the wet-dry cycle.Ion concentrations include sodium,magnesium,chloride and sulfate ions.Correct and validated data processing methods are a necessary condition for the rational and effective analysis of data and for the complete establishment of a database.In this study:(1)Cluster analysis method divided 37 types of cement in different cement standards into five types of cement varieties,which effectively solved the problems of complexity and numerous cement varieties;(2)Summarized the existing research,the equivalent conversion between the cement comressive value tested in the ISO and the ASTM test system are carried out,so that realize the comparability between the data;(3)Similarly,the 150 mm cubic specimen are selected as a reference.And the experimental results of the existing standardized size of the specimen strength values are referred.the strength values of the different sizes of cylinders and cubes specimen are equivalently conversed and a comparability is reached;(4)mol / L is selected as the unit of the ions concentration to realize the unification of different experimental solution ion concentration and the ocean(5)Under the actual marine environment,there is a big difference between the wetting and drying system of tide zone and spatter zone and the laboratory wet and dry cycle system.In this study,a cosine function fitting tidal curve method was used innovatively.Through the BLM-Shipping software,tide height in different sea areas are recorded and being used to fit the cosine curve,and finally the drying and wetting time can be calculated.Thus the wet-dry cycle system in the marine environment can be obtained;(6)Through Regression analysis,ExpectationMaximization method,K-means complement method,missing data in the rough data can be complete supplemented.Data mining is an effective way to further analyze the data base.In this study,descriptive statistics were used to calculate the commonly used statistical characteristics of the data to describe the central tendency,discrete attributes and distribution of the data of concrete strength and influencing factors in the marine environment.In addition,the correlation coefficient between strength and influencing factors was calculated through correlation analysis.The Gray Relational Analysis method(GRA)was used to calculate the gray relational value between strength and influencing factors.The main influential factors were analyzed by Principal Component Analysis(PCA).According to the results of three kinds of mathematical statistics method,the impact of the main influencing factors were summarized and explained.The results showed that initial strength,sulfate ion concentration and silica fume were the most influential factors,while the influence of sodium ion,cement type and sand rate on strength was lower than other influencing factors.The establishment of a database of concrete strength and its influencing factors under the marine environment is the ultimate goal of this study.As a result,a secure,convenient and efficient data management system,SQL Server,is used as a data storage and retrieval tool.This study mainly through the creation of Transact-SQL statement to complete the establishment of databases and data tables.This research innovatively applies the multiple statistical and probability theory method to the data mining of concrete strength under the marine environment.Based on the results of the existing experimental studies,this study realizes the whole process of data collection,data processing,data mining analysis and knowledge representation.A final completion of the marine environment,concrete strength and its influencing factors database was successfully established.