COMPARING DIFFERENT COMPOSITIONS OF RECYCLED GLASS IN CONCRETE

Transcription

1 COMPARING DIFFERENT COMPOSITIONS OF RECYCLED GLASS IN CONCRETE COLTON MOORE DR. MARY CHRISTIANSEN DEPARTMENT OF CIVIL ENGINEERING UNIVERSITY OF MINNESOTA DULUTH

2 TERMINOLOGY Cement Powder substance that is finer than sand An ingredient in mortar and concrete Mortar Ingredients can contain: cement, fine aggregate, and water Concrete Ingredients can contain: Cement, course aggregate, fine aggregate, and water

3 TERMINOLOGY CONTINUED Supplementary Cementitious Materials (SCM) Used as a replacement for portland cement Materials used are either recycled or natural Two types of reactions: Hydraulic reaction Pozzolanic reaction Hydraulic Reaction A material high in calcium (CaO) Reacts with water to form a cementitious bond Pozzolanic Reaction A material low in CaO, but high in silica (SiO 2 ) or alumina (Al 2 O 3 ) Must be mixed with a material high in CaO to form a cementitious bond

4 CEMENT ON THE ENVIRONMENT One of concrete s main ingredient is cement In 2015, portland cement production produced about 4% of the total global CO 2 emission Replacing cement has been under research for a long time The only way to replace cement is to find a material that can form a strong bond when mixed with water A new material being looked at is recycled glass

5 GLASS Most common type of glass is soda-lime glass Two types of soda-lime glass Container Glass Bottles and jars Plate Glass Windows Recycled glass goes through a process so that it can be turned back into new glass containers Not all glass is made into new containers due to impurities, cost, or mixed colors and this glass ends up in landfills In 2014, Americans generated 11.5 million tons of glass with about 26 percent recovered for recycling To help combat the amount of glass ending up in the landfills, other research is being done to utilize this glass like using it in concrete

6 WHY USE GLASS AS A POZZOLAN? Glass is a recycled material that does not belong in landfills Geographically available The composition of glass consists of high silica and low calcium ensuring a pozzolanic reaction Glass has an amorphous structure meaning that it will be reactive with cement and water Glass can be ground to a fine particle size Large surface area ensuring that the glass will be reactive Composition Soda-Lime (Container) Soda-Lime (Plate) SiO 2 (% by weight) Al 2 O 3 (% by weight) B 2 O 3 (% by weight) CaO (% by weight) Na 2 O (% by weight) K 2 O (% by weight) MgO (% by weight) Fe 2 O3 (% by weight) Borosilicate (Labware)

7 GRADATIONS OF RECYCLED GLASS The finer glass is, the better it will react but it costs more For performance and cost, glass needs to have a size under 45 micrometers

8 ASTM C311 Standard test method for sampling and testing fly ash or natural pozzolans for use in portland cement concrete Contains many different chemical analysis tests and physical tests to prove the effectiveness of a pozzolan Strength activity index tests the compressive strength and flow of a test mixture and compares it to a control mix

9 COMMON SUPPLEMENTARY CEMENTITIOUS MATERIALS SiO 2 Silica Fume Common materials used as SCMs Fly Ash (Class F and Class C) Slag Silica Fume Metakaolin Glass??? Composition is key PC Container Glass Class C Fly Ash Slag Class F Fly Ash Metakaolin CaO Al 2 O 3

10 GLASS COMPOSITION

11 SCOPE Making mixtures of different types of glass Two different replacement rates Run compressive strength Examine the flow Look at the structure of an odd ones in Scanning Electron Microscope (SEM) Possibly do freeze-thaw and air-void tests on the best few glasses

12 PRELIMINARY DATA Testing was done to ensure the flow was in range and predictions were close Five different container glasses were tested Testing following strength activity index (ASTM C311) Control mix consists of portland cement, sand, and water Test mix consists of portland cement, sand, water, and glass powder (glass powder replaced 20% of portland cement) Tests were conducted on 7 days and 28 days Total of 36 mortar cubes (6 cubes of each mix, 3 cubes for each break day) Material Portland cement 480 Mass (g) Sand 1650 Water (w/c ratio 0.484) 285 Glass powder 120

13 RESULTS To be a good glass to use in concrete, ASTM C618 states that the strength gain of the test mixture should be within 75% of the control mixture Strength Gain by 28 days C: 93.6% D: 89.7% P: 93.7% Q: 101.4% R: 90.5% These five glasses have a strength gain higher than 75%

14 CONCLUSIONS Portland cement Produces high amount of CO 2 SCMs are needed to replace cement Recycled Glass Geographically accessible Composition and cell structure is good to replace a portion of cement From preliminary tests, recycled glass looks promising to use in concrete as a pozzolan Global Impact If recycled glass is successful as a pozzolan in concrete then there could be a market for the recycled glass to help lower the amount put into landfills Less glass in landfills and less cement being used will help lower CO 2 emissions and other pollutants

15 THANK YOU Dr. Mary Christiansen, research advisor Dr. Andrea Schokker, committee member Glass donations

16 REFERENCES Concrete Percentage Picture (Slide 2): SCM Picture (Slide 3): Kosmatka, Steven H., and Michelle L. Wilson. Design and Control of Concrete Mixtures. 16th ed. Skokie, IL: Portland Cement Association, Print. Recycling Picture (Slide 4): Glass Trash Picture (Slide 5): Glass Bottle Picture (Slide 5): ASTM Symbol (Slide 8): Thank You Picture (Slide 13): Olivier, Jos G.J., Greet Janssens-Maenhout, Marilena Muntean, and Jeroen A.H.W. Peters. "Trends in Global CO2 Emissions: 2016 Report." PBL Netherlands Environmental Assessment Agency, Nov Web. 21 May Shelby, J.E. (2005). Introduction to glass science and technology (2 nd ed.). Cambridge, UK: The Royal Society of Chemistry. Doi: /

17 QUESTIONS?