Concrete Quality

AZ PowerWash Pros

AZ PowerWash Pros

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I have noticed that concrete that was laid in the 1970-90's is much better quality and more durable than concrete laid in late 90's and 2000's. Could this be contractors cutting back on expenses? Buying worse quality cement? Or cutting back on labor expenses rushing workers?

Has anyone else noticed this trend? Maybe its just coincidence on some of my properties. Would like some feedback...

Thought I would ask since I have dedicated a new website strictly to concrete cleaning in Phoenix.
 
Its not the concrete, they have to pass a test when the truck leaves the yard. Everyload is tested and recorded, its the finishing that is the problem.

They just simply ad more water when the truck gets there so they can work faster. This makes the concrete weak.

Residential is 4000 psi and commercial is 6000 psi

You never find residential up to par ever. Maybe if its the finishers family or if the people are picky and mention this before.

Commercial is usally inspected better and kept to a higher standard.
 
Ron is correct. Or if you try to work it too soon before the water can surface and evaporate. What usually happens is they are trying to work it with too little help and it starts to get away from them and they add water. Ether way it mixes too much water on the surface then dries resulting in a very weak surface.

Up north here it shows up after the first hard winter. Or if someone uses salt to melt ice.
 
There is a 45 minute "load time" from the time the batch leaves the plant to when it needs to be poured. Quality control is done both at the plant and on site. Quality measures onsite are required for all structural pours, but are rarely done for sidewalks, driveways, etc.

The problems with the building boom of the past 15 years evolved several changes to "craftsmanship". The cheap, inexperienced labor force, many illegal, was chosen over journeyman craft workers, and their supervisors were chosen for their bilingual abilities rather than proven Journeyman skills.
As an excavation contractor since 1989, I witnessed the decline in quality workmanship, especially noticeable was the concrete crews, since I primarily excavated foundations and structural footings. Occasionally I would do dry and wet utility digs in housing tracks, would witness 4 to 5 mixer trucks lined up, waiting to pour driveways, sidewalks, etc. Many loads went way past their 45 minute critical period, so the contractors would add more and more water to the mix, which destroys the intended density and, as related to PWing, ruins the "cream" consistency.
Hence when spinning and popping gum on large commercial projects and some residential projects, you may notice some slabs react differently than others.
I've also heard it take concrete 50+ years to completely cure, don't know if that is true or not, but concrete that's dexterity was compromised by adding too much water will never repair itself over time.
 
I read they did a core test in 1995 on the Hoover dam built in 1935 and it was still gaining strength. Don't know it as a fact. I too was in the construction business for many years and it all went to crap with cheap labor and production homes.
 
Yes that's correct, core samples have increased strength.

Remember that because concrete is substandard it doesn't mean your not responsible for damaging.

Concrete can be clean safely in most cases.
 
Grime Busters said:
There is a 45 minute "load time" from the time the batch leaves the plant to when it needs to be poured. Quality control is done both at the plant and on site. Quality measures onsite are required for all structural pours, but are rarely done for sidewalks, driveways, etc.

The problems with the building boom of the past 15 years evolved several changes to "craftsmanship". The cheap, inexperienced labor force, many illegal, was chosen over journeyman craft workers, and their supervisors were chosen for their bilingual abilities rather than proven Journeyman skills.
As an excavation contractor since 1989, I witnessed the decline in quality workmanship, especially noticeable was the concrete crews, since I primarily excavated foundations and structural footings. Occasionally I would do dry and wet utility digs in housing tracks, would witness 4 to 5 mixer trucks lined up, waiting to pour driveways, sidewalks, etc. Many loads went way past their 45 minute critical period, so the contractors would add more and more water to the mix, which destroys the intended density and, as related to PWing, ruins the "cream" consistency.
Hence when spinning and popping gum on large commercial projects and some residential projects, you may notice some slabs react differently than others.
I've also heard it take concrete 50+ years to completely cure, don't know if that is true or not, but concrete that's dexterity was compromised by adding too much water will never repair itself over time.
Click to expand...


+10 Too many stops along the way, people not knowing that adding water will weaken the mix or just don't care and very greedy companies trying to pour all they can as fast as they can instead of doing quality work.
 
A few months ago a freeway contractor here had to rip out about 5 miles of a brand new concrete retaining wall seperating the eastbound and westboaund lanes near where I live because it didn't pass a 30 day test. I don't know for sure who ate it on the job but from what I heard it was the contractor.

If you want to hear something scary over 90% of the freeway bridges here in California have failed federal inspections for earthquakes.
 
Vince Wood said:
A few months ago a freeway contractor here had to rip out about 5 miles of a brand new concrete retaining wall seperating the eastbound and westboaund lanes near where I live because it didn't pass a 30 day test. I don't know for sure who ate it on the job but from what I heard it was the contractor.

If you want to hear something scary over 90% of the freeway bridges here in California have failed federal inspections for earthquakes.
Click to expand...

Structual concrete is held to higher standards. Inspection pre, post and weeks after are manditory.

Slump test at the plant and while concrete arrives and while being poured are mandatory by law. Plus it reduces liabilty of the supplier.
 
Like Ron and others have stated, commercial and freeway to secondary road quality standards are much more stringent and followed by regulation. Many are post tension slabs using 6000 to 8000 PSI spec. These projects quality standards are not compromised, as a rule, and tend to have a professional chain of command and accountability.

Look at how many residential slabs are failing, especially in the valley over the past 10+ year building boom. Sub grades where not properly prepared, using native soil high in sand and silt, which will never retain it's required moisture content and density (compaction) load testing requirements. The quality constructed foundations where built using post tension slabs, which are the industry standard for all commercial and industrial projects.
 
Grime Busters said:
Like Ron and others have stated, commercial and freeway to secondary road quality standards are much more stringent and followed by regulation. Many are post tension slabs using 6000 to 8000 PSI spec. These projects quality standards are not compromised, as a rule, and tend to have a professional chain of command and accountability.

Look at how many residential slabs are failing, especially in the valley over the past 10+ year building boom. Sub grades where not properly prepared, using native soil high in sand and silt, which will never retain it's required moisture content and density (compaction) load testing requirements. The quality constructed foundations where built using post tension slabs, which are the industry standard for all commercial and industrial projects.
Click to expand...

In the last ten I have rarely seen the standards held, its a shame
 
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