Recycled Concrete Aggregates

ET 493-FALL 2013

INSTRUCTOR: CRIS KOUTSOUGERAS

ADVISOR: MOHAMED ZEIDAN

BY: CHASE CHARRIER AND GARRETT TREGRE

Introduction Comparing RCA to Typical Aggregate

1. Performance Analysis

2. Cost Analysis

RCA Typical Aggregate

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

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 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

Slump Test

Air Content TestASTM 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

Design Mix

Design Mix – Testing Results

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 measured by filling the abrasion cavities with modeling clay

AnalysisTypical Aggregate vs. RCA

Compare performance is cases of: Strength Durability Workability

Perform cost analysis

Timeline Researched typical concrete mixtures: Fall 2013

Created concrete design mix: Fall 2013

Ordered materials: Fall 2013

Conduct trial mixtures/Fresh properties testing: Jan – Feb 6, 2014

Strength and Durability Testing: Feb – Mar 2014

Cost and Performance Analysis: April 2014

Final Report Preparation: Apr-May 2014

References 1. ASTM Standards: C143, C231/C231M-10; C39; C496; C779

2. “Concrete Air Entrainment Tests.” Durham Geo Slope Indicator. Durham Geo-Enterprises, Inc. durhamgeo.com. Web. 4 Dec. 2013.

3. Gee, King W. “Use of Recycled Concrete Pavement as Aggregate in Hydraulic-Cement Concrete Pavement.” U.S. Department of Federal Transportation. Federal Highway Administration. 3 July 2007. Fhwa.dot.gov. Web.

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

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

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

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