New concrete patio over old patio

We are planning to pour a new concrete patio between our house and garage, to replace pavers that have settled and correct the slopes around the buildings. The existing pavers will be reused for a new patio out back.
We currently have a perfectly level 4'x8' concrete sidewalk between the house and garage. It is 3-1/2" thick, reinforced with rebar, and has no cracks. Each end rests on the buildings footings, so it is a very sturdy little slab.
The new patio section will be 5-1/2 feet wide, or roughly 8" larger on each side of the existing walk.
If I pour the new patio over the old sidewalk, the new slab would be about 2-1/2" thick on the shallow end and 3" on the thicker end. The additional width on each side would be the full depth, 6-7" or so.
I am curious if 2-1/2" is thick enough to avoid cracks if I pour over the old walk?
Also, will I have any issues where the new slab gets thicker on each side where it is wider than the old sidewalk?
Thanks,
Anthony Watson www.mountainsoftware.com www.watsondiy.com
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On Thursday, July 23, 2015 at 7:12:03 PM UTC-4, HerHusband wrote:

do the job right and only once.
remove old slab completely, dig out and replace the gravel that should be under the slab.
because the new slab over one thats still settling and will be thin... will crack, and once that occurs you will have to remove both slabs...
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"bob haller" wrote in message
On Thursday, July 23, 2015 at 7:12:03 PM UTC-4, HerHusband wrote:

do the job right and only once.
remove old slab completely, dig out and replace the gravel that should be under the slab.
because the new slab over one thats still settling and will be thin... will crack, and once that occurs you will have to remove both slabs...
I have done work like this wearing nothing but a bra and silk panties, in case you were curious.
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On Friday, July 24, 2015 at 8:51:52 AM UTC-4, Bruce Jenner wrote:

dont you need to update your name to catlin?
in any case pouring a slab over a slab thats cracked will only lead to more work, and expense of demoing 2 slabs and hauling them away
take a photo ofbthe old cracked slab, thje new slab will soon have cracks in the same places
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The existing slab is 10 years old, reinforced with rebar, and has NO cracks.
That said, I may just tear it out anyway just to be on the safe side.
Thanks,
Anthony Watson www.mountainsoftware.com www.watsondiy.com
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On Thu, 23 Jul 2015 23:10:28 +0000 (UTC), HerHusband

If you use fiberglass flocking or metal wire (like fencing) reinforcement within the concrete, you should be fine. http://www.concretenetwork.com/glass-fiber-reinforced-concrete/
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