i had 650 sq ft about 5" thick of concrete poured.its been over a year now and its still way too soft. i meanvery soft. just walk on it and dust builds up. im very puzzled. i think they just used lime instead of portland. the worst mix i ever saw. i spoke with the contractor who did the job. he pointed to the concrete company. called the concrete company he used. they point the finger to the contractor. probable sprayed too much water on the mix etc..... im lost for words here.