As I've stated before here Concrete can be a little temperamental. I grew up in the Industry as several Family members we're contractor's and several Hustled on the Side. There are so many variables that go into the Work, weather, material and there are several different opinions! As a Contractor of over 30 years I never once had to tear out a job the went bad and due to so many problems that other Contractors we're having in our area yrs. ago. Several jobs are 30 years or older and still look good and are servicing the customer well. I leaned more to the Structural side of Construction in Foundations and the Excavating side of the work that grew beyond my wildest expectations! We we're good and Successful,(another story).
The Cement to water ratio and clean Sand and Stone is very important as much as how long the load was Batched before your contractor installed it in a timely fashion. It's important that the material, Concrete, didn't get over worked. On State dedicated projects here inspectors will not let workers use a Rake as the Tines separate the material by over working it and spreading it too much. A solid bladed tool, Square shovel, come along, are preferred and acceptable. Placing the Material one time and not moving it around is another. Today's material is slammed with chemical's as everything is about the $$$! Substituting Cement,(Concrete's main ingredient), with Chemicals has been an ongoing practice for several years now and it never was a good Idea IMO! When I would contract a job for a friend or relative as a so called favor I would place the order with the Material Specs. I wanted!!! My Name was on the Project and no one else's! I had a great team I would put together as was needed and paid everyone well! I'm sure that you paid well for your work as Concrete work is hard work and the material isn't cheap. Too many contractors spray water on top of the laid Cement as it's the worst thing you can do as it weakens the Top hence promotes peeling and scalding concrete. Bleed water from an over saturated base will help to cause these problems too. Like I said in the beginning there are many Variables to Concrete Work. Contact your contractor and try to work with them!!! The squeaky wheel gets the Grease, so to speak. Unfortunately the only way to fix it properly is to replace it! There are many a suggested Band Aid fixes that are just that! BAND-AID FIX!!! It will never be Right and it may be confined to a small area now but it can spread and get worse over time and Grow! A contractor never knows what comes in that Truck and he only knows what he ordered. The Mix design on a printed ticket will show exactly what was ordered and what's in the load or loads and the time it was dispatched to the times of installation! Most modern day tickets are Computer time Stamped!!! We've all heard so many Concrete horor stories where everyone is an expert today because Uncle Louis was the Best and or Joe did me a solid as he did a side job for cash. Those deals work out sometimes and I get it but if and when there might be a problem you don't have a lot of recourse with no permits being drawn and the installer not being licensed and Bonded with no Insurance! Most inspectors don't know what their looking at any ways as each one has their own story to tell. That's where a good Contractor comes in and there's a lot of good Hard working Honest Contractor's out there! This topic can go on and on and I'm trying to condense it as much as possible. Good Luck and keep us posted!
LtF