COMPUTER DATABASE FOR CONCRETE ...

COMPUTER DATABASE FOR CONCRETE SPECIMENS AT A MARINE EXPOSURE SITE Irina L. Kondratova, University of New Brunswick, Canada Ilia A. Goldfarb, New Brunswick College of Craft & Design, Canada Theodore W. Bremner, University of New Brunswick, Canada Mohan V. Malhotra, Canadian Center for Mineral and Energy Technology, Canada

Abstract In 1978 CANMET recognized the need to evaluate various types of concrete for their performance in cold marine exposure conditions. In the following years, series of concrete prisms, dimensions 305x305x915 mm, were cast. They incorporated mixture proportions and constituents that were likely to be used to construct public and private facilities in the future. These prisms were placed at a mid-tide wharf at Treat Island, Maine, in the Bay of Fundy near the Canadian border. The annual concrete testing, sponsored by CANMET, involves over 300 specimens of various ages and types. Each specimen is photographed, visually rated and tested for pulse velocity and resonant frequency. The study generated over 10,000 units of data and more than 3000 color photographs. In 1995 the Department of Supply and Services awarded a contract to the University of New Brunswick, for the development of a computer database for the concrete specimens exposed in the marine environment at Treat Island, Maine. This paper discusses some issues associated with the design and maintenance of the database.

Keywords: concrete, database, long-term exposure, supplementary cementing materials

Paper presented and published in the Proceedings of the First International Conference on New Information Technologies for Decision Making in Civil Engineering, Montreal, October 11-13, 1998, Vol.2,pp.803-811

1. Introduction The Canadian Centre for Mineral and Energy Technology (CANMET) has an ongoing program dealing with the long-term performance of supplementary cementing materials in concrete (Malhotra and Bremner, 1996). This program focuses on the use of fly ash, pelletized and granulated blast-furnace slag and silica fume as a replacement for the high energy content portland cement (6570MJ/tonne) which representing 42% of the total concrete production energy cost (Malhotra, Berry et al, 1980). An added benefit from using these supplementary replacement materials is that with each tonne of cement conserved, a saving of one tonne of CO2 is achieved, thereby reducing the construction industry contribution to global warming. So that these supplementary materials (industrial by-products) can be used in marine concrete in a way that they will not adversely affect the long-term durability of the concrete, CANMET in 1978 started a comprehensive testing program that is still continuing. On the past two decades, series of concrete prisms were cast, with and without various amounts of supplementary cementing materials, to identify, to what extent these supplementary cementing materials can be incorporated in concrete to produce durable marine facilities. To evaluate the concrete specimens (prisms 305x305x915 mm) were placed at an outdoor marine exposure facility operated by the US Army Corps of Engineers, Vicksburg, Mississippi. The site, located at Treat Island in Cobscook Bay near Eastport, Maine, is near the Canadian border, and is at the entrance to the Bay of Fundy. At the site, the test prisms are positioned on a rack at midtide level, so that they are exposed alternatively to a marine atmosphere, and immersion in seawater twice daily. The alternating cycles of immersion and exposure to air provides over 100 cycles of freezing and thawing per year. Based on experience, acquired at the site over the past six decades, has shown that specimens that successfully resist these exposure conditions will normally provide good long-term performance in marine facilities. All specimens are inspected each year. Inspection includes photographing, visual examination, visual rating, and measurement of pulse velocity and resonant frequency of each specimen. The voluminous data generated was normally handled manually, however the size of the files and the need to examine the visual appearance (from the photographs) and consolidate that with the measurements has became unwieldy, and as a result a computer database has been proposed. 2. Database design 2.1. Database management software In order to access and compare the accumulated data easily and efficiently, a database management system was utilized, and a database with the potential to store all records, hold photographic images and graphs, and perform search and query operations, was created. Microsoft® Access for Windows® 95 software, a part of the Microsoft® Office Professional Software package for Windows®95, was chosen as the database management system for this project. This system includes a graphical design environment for creating and modifying tables, forms, reports, queries and macros and enables the user to place graphics in forms and reports. Thus records on a singular datasheet can contain a word-processing document, spreadsheet, or a graphic image. In 1998 the database was updated to Microsoft® Office Professional 97 version.

2.2. Interface design 2.2.1 Menu design The database interface includes three menus. The Main menu allows the user to choose among three different formats of data presentation, as well as, to go to two other menus - Reports menu and Forms menu.

Fig.1. Main and Reports Menu

2.2.2 Format A In the database design, three data representation formats are available. Format A allows the selection of specific specimens from a table, so that the photographs of the specimens can be displayed on the computer screen. This enables different specimens of similar age to be compared. Data in Format A is presented as a table with all the essential information about the concrete specimens, including phase of the project, year when specimens were placed at the exposure site, age of the specimen when the photographs were taken (5, 10, 15, 20 etc.) and details of the mixture proportions. The user can choose which specimens to review by checking the checkbox.

Fig.2. Format A screen design After choosing the specimens to review and closing Format A window, the user returns to the Main menu. Now, the user can choose the option of generating a query on the data format A, in the Reports menu. The query is displayed in a report form (up to four specimens on one page) with an unlimited number of pages to be displayed. The report can be viewed on a computer screen, and a copy of the generated report can be printed. This format gives the concrete specialist a unique opportunity to view and compare, side-by-side, the visual history of different concrete mixtures, evaluate the performance of concrete specimens with supplementary cementing materials in severe marine exposure conditions, and to make informed decisions about the choice of materials for a particular project.

Fig.3. Format A generated report 2.2.3 Format B Format B enables selection of a specific specimen from a table and displays photographs of it taken at 5, 10, 15 and 20 years of exposure, along with individual specimen descriptions. Data in Format B is presented as a table, with all the essential information about concrete specimens including phase of the project, year when the specimens were placed at the exposure site, and details of the mixture proportions. The user can choose specific specimens to review by checking the checkbox. After choosing the specimens to review and closing the Format B window, the user returns to the Main menu, and once again has the option of generating a query on the data format B, by enabling it in the Reports Menu. This query is displayed in a report form with an unlimited number of displayed pages. The report can be viewed on a computer screen and a copy of the report can be printed. This format enables the specialist to generate reports easily on the performance of a particular type of concrete at the Treat Island long-term marine exposure site.

Fig.4. Format B screen design

Fig.5. Format B generated report

2.2.4 Format C Format C enables selection of a specific specimen from a table, with a display of the visual rating, pulse velocity and resonant frequency testing data for all years, as a graph of performance vs. years of exposure, along with a detailed description of the specimen and its most recent photograph.

Fig. 6. Table Format C

Fig. 7. Report Format C

2.2.5 Forms format Forms menu allows the user to choose among three different form formats. Forms are used as index cards for every specimen with all the data entered in the form in a convenient visual format. Below is an example of the Format A form design.

Fig.8. Form Format A design Pulse velocity and resonant frequency testing is being done every year on-site at Treat Island during the annual inspection of the specimens. Each year the graphs in the database are updated with current numbers right inside the database on the form format C. All the graphs are in MS Excell format and are inserted into the page. They are editable inside the database, or they could be linked to the spreadsheet files and updated automatically when the corresponding spreadsheet files for resonant frequency, pulse velocity testing data, and visual rating data are being updated. 2.2.6 Photographic records The photographs of the specimens exposed at Treat Island site are taken annually. Up to 1996 photographs and slides of all of the individual specimens were taken with a 35-mm film camera and then stored for a future reference. In order to enter these records into the database, photographs or slides of the individual specimens needed to be digitised. Starting with the summer of 1997, a digital camera is being used for taking photographs of the specimens at the exposure site. This enables convenient storage of the photographs and easy incorporation of new photographs into the database.

3. Conclusion The computer database provides an informative and flexible means of accessing the data from the study on the performance of concrete in the marine environment, and should be of a particular use in selecting constituents for durable concrete mixtures that reduce both, energy consumption and CO2 emissions. 4. Acknowledgements This project was carried out under contract with funding from the Canadian Centre for Mineral and Energy Technology (CANMET).

5. References MALHOTRA, V.M. and BREMNER, T.W., (1996), " Performance of Concrete at Treat Island, U.S.A.: CANMET Investigations", Proceedings Third CANMET/ACI International Conference St. Andrews by-the- Sea, Canada, 1996, ACI SP-163, pp.1-52. MALHOTRA, V.M., BERRY, E.E, and WHEAT, T.A., (1976), Proceedings, "Seminar on Energy and Resource Conservation in the Cement and Concrete Industry", CANMET, Canada Energy, Mines and Resources, Ottawa, Canada.

Full addresses of the authors: Irina L. Kondratova, Department of Civil Engineering, University of New Brunswick, P.O. Box 4400, Fredericton, N.B., E3B 5A3, Canada Ilia A. Goldfarb, New Brunswick College of Craft and Design, P.O. Box 6000, 15 Carleton Street, Fredericton, N.B., E3B 5H1, Canada Theodore W. Bremner, Department of Civil Engineering, University of New Brunswick, P.O. Box 4400, Fredericton, N.B., E3B 5A3, Canada Mohan V. Malhotra, CANMET, Energy, Mines and Resources Canada, 405 Rochester Street, Ottawa, Ontario, K1A 0G1, Canada