I was helping a neighbor last weekend pour a 7.5 yard concrete patio as a grunt. He had a couple of other people their that seemed to at least sound like they knew what they were doing. I'm not claiming any real knowledge of concrete.

Problem was that the driver shorted them or my neighbor mis calculated his concrete needs.

The decision was made to run to lowes "quickly" to get bagged concrete to supplement the lack of pre mixed concrete from the truck.

They mixed and added 8 bags of quickrete to the already poured concrete and finished the job.

It was a pretty cool day....low 60's and over cast so the poured concrete didn't set to quickly which allowed them to get back with the sacks before the other stuff set.

Wondering what kinds of issues this could create in the future for my neighboor.

It's clearly a different color from having to different materials but he plans to stain it to take care of that issue.

 

I don't see a problem other than the mismatch in color. If he had used Portland & sand, it might have matched.

 

Unless they mixed the new with the old REALLY well, it's possible that a crack (or cracks) will develop along and around the area where the new mix was added. This usually occurs as the cement cures, different mixes will contract at a slightly different rate. Same thing can happen where one cement truck ends and another begins.

 

I'm confused about the driver "shorting" the customer. The few times that I've ordered the delivery was metered as it came off the truck. Concrete was delivered according to what was needed for the project, not according to my estimate.

 

Think I would have ordered 8 yards if buying a specified amount.

 

Yeah, I agree with Wayne, that unless they are dishonest or have unexpectedly run short from delivering too much to the last guy, (some trucks will make 2 deliveries from the same batch) cement trucks don't short people. If anything they are usually a little long. The additives are measured by a computer as they are added to the truck, so I would doubt there is a mistake there. We can order in any amount to the closest 1/4 yd.

It's more likely that the patio wasn't screeded to an exact depth, or if it was backfilled and screeded, it wasn't tamped and so it compacted under the weight of the cement which means there is more volume in the patio than what was measured. But most guys ego's won't allow them to admit they made a mistake so they shift the blame. LOL

But if he ordered 7.5 and got billed for 7.25 then he obviously did get shorted.

 

Around here trucks carry only one delivery. There is no metering or measuring device. How can a truck measure out 2 yards in the field?

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You would have to laugh if you ever saw them pour a driveway in Central America. Usually there is no ready mix truck. Just a flat bed with pallet loads of bagged cement or concrete mix. Bags get poured out into a pile, a crater is made in the center and water added. The concrete is mixed right there on the ground inside the forms. They keep repeating the process until the job is done.

 

There are trucks that carry everything dry and mix it as needed on site.

 

The trucks around Indy (and I assume Columbus, Ohio too) carry one person's load at a time and bring the amount you tell them to bring. Batch plants are computerized and it would be a rarity that they "short someone". It's almost always contractor error.
An example: Monday I poured a stamped patio for another contractor. He did all the forming and prep, and ordered and paid for the concrete. He told me it was going to be about 600 sq ft. He planned on ordering 8 yards of colored concrete. When I got to the job I saw it was nowhere near that large. After measuring, I came up with 282 sq ft. (3.45 cubic yards). He didn't believe me when I told him the actual square footage two days before the pour. He went ahead and ordered based on his measurements. His mistake and bullheadedness cost him over $525 in unused concrete (4.5 yards) which was sent back to the plant and dumped out.
As to your question, there will probably be no bad effects other than the color difference. However, since bagged concrete mix is not air-entrained and the ready mix presumably was, he may have problems with scaling on the hand-mixed section next winter.

 

we KNOW those guys - they left so america & are here in atl tried to place a d/w addn for a friend of mine w/180b of apron store conc mix & a garden hose,,, owner/contractor came by & almost had a stroke

usually if you're short conc, its your fault for not prepping the site correctly OR you can't use a calculator right short loads from plants ? - not here,,, the fun's when you're 50' short of the 16" bulkhead & trying to order the last loads from the plant

some folks have trouble w/calculators even if they're contractors

 

You guys are correct in saying that it was only our concrete on the truck. As it was, all the deliveries that day canceled because of the threat of rain. My stubborn friend threw a fit when they concrete company tried to cancel on him being that he was the only delivery that saturday that didn't cancel on their own. They ended up coming but there was no chance in the world that you we were going to be able to get that driver to go back to the plant and mix more concrete.


My guess is that the calculations was way off. Knowing my friend, he is way to bullheaded to say that he miscalculated.

Mostly I was just interested in knowing if there would be any ill effects by mixing the two different materials on-site in a hurried fashion.

Another issue that day was that the concreate had been finished for about 10 min when a strong but short storm came through. 15 min at the most but a lot of hard rain. they were able to "smooth" over the rain dimples but I have to believe that the rain will have an ill effect on the concrete as well as the mixing of quickrete in with the delivered load.

thanks again for all of your thoughts.