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 MyMason's Case Studies

 Chimneys and Brickwork Case Studies

    Chimney Repair

    Chimney Repair, Articulated Boom

    Custom Scaffold, Chimney Repair

    Lower-Chimney's Removal, Wall Restructuring

    Chimney Flue Replacement

    Concrete Chimney Cap as per Building Code

    Chimney - Sloped Side, Repair

    Chimney - Wobbly Chimney

    Brick Pillar

    Brick Garage Pillar Repair

    Window's Lintel Installation

    Brick Sill Creates Wall Damage

    Brick-to-Stone Window Sill Replacement

    Brick Retaining Wall Rebuild

 
 Concrete Case Studies

    Broken Concrete Step

    Basement Window, Concrete Cut

    Basement Window, Concrete cut-out

    Concrete Walkway, Landing

    Concrete Stairs and Landing

    Concrete Stairs and Landing

    Concrete Countertop

 
 Stone Work Case Studies

    Stone Wall Rebuild

    Granite Resurfacing of Concrete Stairs

    Stone Step Rebuild

    Stone Stair Rebuild - in Winter

    Stone replaces Brick Door Sill

    Stone Retaining Wall Rebuild

    Dry-Stack Retaining Wall Rebuild

    Dry-Stack Stone Retaining Wall

    Flagstone Patio Rebuild, Expansion

    FlagStone Step Repair

    Stone Replacement

    New Interlocking Stone Walkway

    Re-setting Interlocking Walkway

    Tile Installation

 
 Algonquin College/MyMason Case Studies

    Cold Weather Masonry Rules

    Salt and Concrete Testing

    Concrete Curing Stress Tests

    Concrete and Rebar Stress Tests

 
 Parging Case Studies

    Parging, Cement Board

    Parging Examples & Techniques

 
 Fireplace Case Studies

    Fireplace Surround - Old Wood to New Wood Insert

    Fireplace Fire Brick Replacement

    Fireplace Surround - Natural Stone

    Electric, Natural Stone Fireplace

    Fireplace Hearth Replacement

    Stone Fireplace

    Cultured Stone Fireplace & New Framing

    Cultured Stone Fireplace Surround

    TV Mounted on Stone Fireplace

    Restructuring Fireplace: Wood to Gas

    Drywall to Stone Fireplace

    3-sided fireplace: Cultured Stone

    Fireplace Removal, Damper Removal
 

 

    Case Study: Concrete and Rebar Stress Tests

 
        Before and After

   

 
 
 
    The Assignment:
        Make Sidewalk Strength Concrete, 32 MPA.
        Use rusted, non-rusted and epoxy coated rebar.
        Position rebar centered and not centered in concrete.
        Measure results, write a report.

 
    The Prep:
        Some of the samples were cracked after curing to allow moisture in.
        Control samples were made as well.


 
MyMason
John of MyMason ready to mix concrete in the Lab.
The Lab is in the ALgonquin College School of Construction Excellence.

 
Measuring the Mix
The Sifter Machine is the first step.
We can then know the nature of our mix's aggregate, very precisely.

 
Measuring
The team puts the concrete mix through a sifter, and then these measures.
They can then accurately measure the aggregate's granular sizes.

 

The Rebar
The key element of our study, the Rebar.
We are comparing how placement and the state of the rebar affects the resulting concrete.

Rusted rebar, unrusted rebar, epoxy coated rebar.
The rebar will be placed in the centre of the form in some samples, and near the edge in others.

The Forms
We built forms to fit the stress testing machine:
6" high and wide, 24" long.

Mixing the Concrete
Here the Portland cement is measured into the mix.
Sand, aggregate, an air-entraining additive, and water are added.

The Aggregate in the Mixer
the aggregate is precisely measured into the mixing machine.

Concrete Slump Test
The wetness of the concrete is measured and recorded.
This metal cone was inverted, filled with concrete, tamped,
and then the cone was removed, and we measure the amount it slumps.
Rebar Set
This epoxy coated rebar is set into the form.

The Form Finished
The rebar is in, the sample coded and marked.
Now a team member smoothes the surface.

 

 

Calculating the Mix
Mixing separate but equal batches requires math skills.

 

 

 

 

 

 

Cleaning our Tools
Keeping the Lab's tools clean is important too.

 

 

Ready for Cutting, Testing
We're taking the concrete outdoors to cut open.

 

 

 

 

 

 

Testing the Control Pieces.
All of the slabs were cracked in this manner.
Most were cracked after a 30 day cure to let moisture in.
Water and salt were then applied to the slabs for a month.
A few were held back to use as controls.

 

 

Ready for Cutting, Testing
We're taking the concrete outdoors to cut open.

 

 

 

 

 

 

Cutting the Concrete
Following the cracks we've previously created,
the pieces are cut open so we can see the rebar.
Has the rust had an effect in less than 2 months?

 

 

The Epoxied Rebar is Great
It doesn't rust, of course.
This affects the way the concrete breaks too
as the concrete isn't further stressed by rust.

 

 

 

 

 

 

Non-Rusted Rebar.
This piece was set near the edge of the concrete.
Despite the induced crack and moisture added, no rust.
But you can see how stress causes it to break easiest where the rebar is close to the surface.

 

 

Rusted Rebar
In less than a month since curing, rust is spreading.
This rebar piece was also set near the surface.
Imagine the results of years of moisture penetration.

 

 

 

 

 

 


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This page last modified: July 30 2011