Recycled Concrete Aggregates ET 494-SPRING 2014 INSTRUCTOR: CRIS KOUTSOUGERAS ADVISOR: MOHAMED ZEIDAN BY: CHASE CHARRIER AND GARRETT TREGRE

Project Overview  Typical Concrete Mixes consist of:  Coarse Aggregate (gravel)  Fine Aggregate (sand)  Water  Cement  Comparing RCA to Typical Aggregate  Performance Analysis for three mixes:  Typical Concrete Mix  RCA Mix with unknown source  RCA Mix with known source  Cost Analysis Typical Coarse Aggregate RCA

Introduction  Concrete industry projected to be a $100 billion dollar industry by 2015  16 Billion tons of concrete produced yearly  2-3 Billion tons of concrete waste produced yearly  Disadvantages of Concrete:  Limited space in landfills caused by concrete waste  Environmental impact on natural aggregate resources  Advantages of RCA:  Solve landfill problems  Help save natural aggregate resources

Purpose  Research and test the effectiveness of RCA’s use in the construction field  Increase RCA’s use in the construction field  Provided an ECO friendly industry through RCA’s

Design and Proportioning  Target Concrete Strength of 5000 psi  Target workability 3”-5”  W/CM Ratio  Durable for sidewalks and pavements

Design Mix – Testing Results

Final proportions Proportions for Standard Mix: 1 YD 3 Proportions for RCA - Unknown Mix: 1 YD 3 Proportions for RCA - Known Mix: 1 YD 3 MaterialLbsMaterialLbsMaterialLbs Coarse Aggregate70.34Coarse Aggregate69.95Coarse Aggregate72.02 Fine Aggregate53.92Fine Aggregate53.92Fine Aggregate53.92 Water10.60Water15.20Water13.15 Cement21.85Cement21.85Cement21.85

Moisture Content Test  Purpose is to determine the amount of moisture residing inside the aggregates  Moisture Content Test helps to insure an accurate concrete mix and desired characteristics  Oven Temperature: 110 – 115 degrees F  A. Weight of empty Container  B. Weight of Container + Wet Sample  C. Weight of Container + Dry Sample (after fixed reading)  M.C. = (B – C / C – A) * 100%

Trial Mixes

Slump Test  ASTM C143 Standard  Measures the mixtures fresh concrete properties  Consistency & Workability- measure of the ease at which the concrete flows  Also measures the consistency between multiple batches of concrete  Different slumps are required for different applications  The slump test measures concrete’s behavior to the force of gravity  More slump = more water and workability  Smaller slump = drier mix with less workability

Slump Test Procedure  Fresh concrete is placed into a metal cone with a diameter of 4” at one end and 8” at the other end being 12” tall  The concrete is placed into the cone in 3 stages and at each stage the concrete is tampered with a 2’ metal rod, 5/8” in diameter  The final stage is to level off the concrete, remove the cone, and measure the slump

Slump Test

Air Content Test  ASTM C231/C231M-10  Determines the amount of air in a fresh concrete mix  Three Methods:  Pressure Method  Volumetric Method  Free Air Method  Pressure applied to fresh sample of concrete to compress air entrained pores  Meter on device measures pressure  Pressure-to-Volume relationship to Boyle’s Law is used to calculate air content

Air Content Test

Compression Test  ASTM C39 standard  Measures concrete’s ability to withstand compression forces  Strength normally relates the overall quality of the concrete  Concrete is molded into cylinders in which the length is twice the diameter and the diameter is three times the maximum aggregate size  After 28 days are given for proper time to cure, the cylinders are tested  Compression test is performed by applying an axial load to the test cylinder at a constant rate until failure occurs

Compression Test

Compression Test Results Average Results of Trials Standard Mix psi RCA Mix (unknown source) psi RCA Mix (known source)4157 psi

Splitting Tensile Test  ASTM C496 standard  Measures concrete’s ability to resist tensile forces  Tensile strength is much smaller than concrete’s compression strength  Test is performed by placing a concrete cylinder horizontally under a compression machine and applying a force until splitting occurs  Concrete Cylinder- common size 150mm by 300 mm

Splitting Tensile Test

Splitting Tensile Test Results Average Results of Trials Standard Mix psi RCA Mix (unknown source) psi RCA Mix (known source) psi

Abrasion Test  ASTM C779 standard for abrasion testing  Measures of concrete’s ability to last over time  We will measure our concrete’s durability through a sandblasting abrasion test  The concrete abrasion test involves spraying our concrete test piece with a sandblaster from a distance of 75 +/- 2.5mm for a length of 1 min.  The volume lost due to abrasion is measured by filling the abrasion cavities with modeling clay

Abrasion Test

Durability Test Results Concrete MixturesAbrasion Coefficient Loss Avg. Volume Loss Standard Mix cm 3 /cm cm 3 RCA Mix (unknown source) cm 3 /cm cm 3 RCA Mix (known source) cm 3 /cm cm 3

Cost Analysis Proportions for Standard Mix: 1 FT 3 Avg. Cost Per TonAvg. Cost per yd 3 MaterialLbs$$ Coarse Aggregate$70.34$13.00$12.34 Fine Aggregate$53.92$12.50$9.10 Water$10.60$1.12$0.16 Cement$21.85$110.00$32.45 Average Cost of Standard Concrete $54.05 Proportions for RCA Mix: 1 FT 3 Avg. Cost Per TonAvg. Cost per yd 3 MaterialLbs$$ RCA$70.98$8.00$7.67 Fine Aggregate$53.92$12.50$9.10 Water$14.18$1.12$0.21 Cement$21.85$110.00$32.45 Average Cost of RCA Concrete $49.43 Total Savings Per yd 3 of Concrete Using RCA8.5%

Conclusion & Recommendations  Reduced Compression, Tensile, and Abrasion Strength  Source of RCA has little affect on overall strength  More Cost Effective  Recommendations:  Reduce W/CM ratio for RCA mix to compensate  Reduce amount of RCA used- 30%, 50%, 75%  Benefits:  8.5% more cost efficient  Saving natural resources  Reduce landfill space

Acknowledgements  Clay Gottschalck, P.E – District 62 Construction Coordinator: Louisiana DOTD Materials Lab  Lab Testing: Compression and Tensile Test  Trey Tycer – Plant Manager/Owner: Tycer Ready Mix  Provided Materials: Coarse Aggregate, Fine Aggregate, Cement  Abita Aggregate Recycling  Provided RCA

References 1. ASTM Standards: C143, C231/C231M-10; C39; C496; C Gee, King W. “Use of Recycled Concrete Pavement as Aggregate in Hydraulic-Cement Concrete Pavement.” U.S. Department of Federal ransportation. Federal Highway Administration. 3 July Fhwa.dot.gov. Web. 3. Kosmatka, Steven H., William C. Panarese, and Beatrix Kerkhoff. "Designing and Proportioning Normal Concrete Mixtures." Design and Control of Concrete Mixtures. Skokie: Portland Cement Association., Print. 4. MacDonald, Kevin. "Crushed Concrete." Concrete Construction. Haney Wood, 30 July Web. 24 Oct “Materials: Recycled Aggregates.” Concrete Technology. Portland Cement Association. Cement.org. Web. 6. "Material Testing." Compression Test on Concrete. Building Research Institute, Web. 25 Oct Osei, Daniel Y. "Compressive Strength of Concrete Using Recycled Concrete Aggregate as Complete Replacement of Natural Aggregate." Journal of Engineering, Computers, and Applied Sciences 2.10 (2013): Web. 2 May Paul, Suvash C., and Gideon V. Zijl. "Mechanical and Durability Properties of Recycled Concrete Aggregate for Normal Strength Structural Concrete." International Journal of Sustainable Construction Engineering and Technology 4.1 (2013): Web. 3 May "Sustainability Report." Canadian Cement Industry. Cement Association of Canada, Web. 3 May 2014.

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