It sounds as if the saw joints were performed too late. Saw
joints and jointer tracks are control joints. Tar joints are
expansion joints. Cold joints are construction joints.

The best dollars spent are on the preparation of the sub grade.
Good compaction, uniform slab thickness, do not allow concrete
trucks on compacted grade are all good practices. I pour most
concrete without rebar or remesh.

Rebar should not continue through joints. I would limit the
distance between saw joints to 12 feet or less. Saw joints should
be performed on the same day as the pour as soon as the slab can
be cut without raveling.

The slab should be cured. GOOD:Cure with curing compound applied
by the contractor immediately after pouring. BETTER: visqueen
cover with water trapped on the slab (this often leaves a mottled
appearance and /or visqueen printing) BEST: total immersion
accomplished by building an appropriate dam around the pour -
usually not possible on sloped drives, etc. The water cure should
be applied for +/- 7 days. Keep heavy objects (cars, trucks, etc)
off the concrete for a minimum of 3 days, preferred 7 days to
allow the concrete to make enough initial strength to deal with
the loads.

These are all givens about concrete. Here is another: Concrete
will crack. The trick is to get it to crack where you want it to,
preferably in a neat straight line. Sometimes there is just no
simple answer to why concrete cracks where it does. Heat
shrinkage, hot rebar, design mix, finishing techniques, wind, hot
sun all have profound effects on concrete.

I hope that you and your contractor can arrive at a solution that
is equitable to both of you. Remember he has a lot of time and
material in this job already. I do not guarantee concrete not to
crack, in fact, I make owners aware of the potential before hand.
I am also aware that you have money and quality expectations that
should be part of the overall resolution.

(top posted for your convenience)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"JJ" wrote in message
. ..
Almost two weeks ago I had 3,100 sq ft of concrete poured for a
driveway and apron in front of the garage. I was told to let it
cure for 7-10 days before driving on it. We gave it 9 days
before pulling one car into the garage.

13 days after pouring, I've noticed I have 3 major cracks in 3
separate sections. The cracks run right through the expansion
joints, from one side to the other of the drive and are spaced
about 20ft apart. They are about 100ft from the garage and
apron sections.

The contractor is coming over this week to check it out and I'm
wondering what demands I can make to cure this? He has not been
paid yet!

What are my reasonable options to fix this?

Thanks,