One of those puzzles involves the downward spiral of concrete quality. I lived on Lansing's near-East side in the late 1980s and we had a sidewalk block stamped "1923". It was in great shape...far better than the blocks poured in the early 1970's. The contractors who were replacing bad blocks must have noticed, too. They jackhammered it out even though it was pristine, if slightly worn. Now the block they replaced it with is crumbling.
My expert used to work for the Michigan Department of Transportation. He told me that the problem was twofold.
The primary problem is that the contractors self-certify the quality of the pour. In itself, self-certification is not a problem. The quality of domestic automobiles has grown by leaps-and-bounds under supplier self-certification. The problem is in the implementation.
The difference between the state contractors and the automotive suppliers is that the State yawns when the contractor falls out of compliance. The automotive companies make the suppliers crawl across five miles of broken glass.
For example: It is mandatory that the automotive supplier
- Perform root cause analysis
- Implement a short term fix
- Identify and quarantine all discrepant material
- Identify and initiate a long term fix
- Certify that all reworked discrepant material exceeds as-new requirements before releasing quarantine
- Pay damages that are determined by a formula: $500/minute to stop the main assembly line, $100/minute to stop a feeder line, $60/hour for every internal person involved in finding and fixing the mess. Plus, the supplier must bear all incidental costs associated with the corrective action.
The automotive system may seem harsh, but it is all about protecting the customer. Further, that pain can lead to some creative solutions.
One example involves interior trim panels. These panels were upholstered in a soft vinyl-like material that was vulnerable to snagging. The other side of the panel has sharp clips that snap into the car body. You guessed it, the sharp clips consistently scarred the upholstery.
The fix that the supplier came up with was to ship the panels in two-by-two (front and rear, actually) with the sharp, pointy sides facing each other. So rather than ship them >>|>>|>>|>> They started shipping them ><|><|>< That solution cost NOTHING but it never would have been found and implemented if the supplier had not been losing hundreds of thousands of dollars to quality issues.
The other problem identified by my expert is the lack of attention paid to the aggregate used in the concrete. Crushed limestone or dolomite is best. Fly ash and crushed concrete is good. Round aggregate is fair. Some aggregate is contaminated with clay clods and organic waste it is is very poor.