Recycled Concrete Aggregates

ET 493

INSTRUCTOR: CRIS KOUTSOUGERAS

ADVISOR: MOHAMED ZEIDAN

BY: CHASE CHARRIER AND GARRETT TREGRE

Introduction Our project will consist of creating, testing, and analyzing concrete mixtures in which recycled concrete aggregates (RCA) and typical aggregates are used

Concrete Basic Components: water, binding material, and aggregates

Concrete’s Structure: will resemble non-load bearing concrete such as pavements and sidewalks

Testing Slump Test Compression Test Tensile Test Durability Test

Analysis Effectiveness of RCA Cost of Typical Aggregate vs. RCA

Background New process

Discovered through finding a process to recycle rather than dispose of old concrete Not yet allowed to be used in load-bearing structures

RCA vs. typical aggregate No significant difference

RCA weakness Existence of impurities

Ex: Soil, loose cement mortar, wood, and oil Most removed through crushing the concrete Hydraulic separation may be necessary for more fine impurities Detailed cleaned creates struggle with cost effectiveness

PurposeResearch 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

1st PhaseThe first phase of this project will include the design of our reference mixture and also the testing of (typical concrete)

Testing will include the slump test, compression test, tensile test, and durability of typical concrete(without RCA) using our reference mix

At the end of all testing, results will be recorded for further analysis

Procedure- Reference Mix Design a reference mix to be used throughout our project

Reference mix- proportion of each material by mass to create structurally sound concrete

We will consider the strength, workability, and durability in the creation of our mix

Experiment with water/cement ratio, aggregate amount and size, air content, and slump

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 ProcedureFresh 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

Compression TestASTM 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

Tensile TestASTM 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

Durability TestASTM 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 measure by filling the abrasion cavities with modeling clay

2nd PhaseAfter initial testing of typical concrete has finished, the 2nd phase will begin, which will include the testing of RCA

RCA will replace the typical aggregate(rock, stone) in this portion of testing

We will use our existing concrete mix (1st phase) and crush it to use as the RCA and also an unknown source of RCA gathered from Tycer Ready Mix, located in Hammond, LA

Design of 2nd MixtureThe design of our 2nd mixture will be the same as the first reference mixture to ensure that comparable results are gathered

2nd TestingExisting RCA

Slump Test Compression Test Tensile Test Durability Test

Tycer Ready Mix RCA Slump Test Compression Test Tensile Test Durability Test

AnalysisTypical Aggregate vs. RCA

Compare performance is cases of: Strength Durability Workability

Perform cost analysis

Timeline/Deliverables Semester 1:

Week 1: October 8-15, 2013: Research typical design and testing Week 2: October 15-22,2013: Design typical concrete mix with typical use Week 3-5: October 22-November 5, 2013: Gather materials needed for first mixture and fresh properties testing; conduct trial

mixtures Week 5: November 5, 2013: Mix first sets of concrete and conduct fresh properties testing Week 9: December 3, 2013: Strength and durability testing for first concrete mixtures

Semester 2: Week 1-2: January 27-February 3, 2014: Recheck mixture design and adjust as needed Week 3: February 10,2014: Mix adjusted sets of concrete and test fresh concrete properties Week 7: March 10, 2014: Strength and durability testing for adjusted concrete mixtures Week 8-9: March 17-24 2014: Results analysis Week 10-11: March 31-April 7, 2014: Cost analysis and comparison Week 12-15: April 14-May 5, 2014: Final Report Preparation

References 1.MacDonald, Kevin. "Crushed Concrete." Concrete Construction. Haney Wood, 30 July 2011. Web. 24 Oct. 2013.

2. "Material Testing." Compression Test on Concrete. Building Research Institute, n.d. Web. 25 Oct. 2013.

3. “Materials: Recycled Aggregates.” Concrete Technology. Portland Cement Association. Cement.org. Web.

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