I work for a ready mix and had an air requirement on top of the mountain. 4000ft gain in the hour it took to drive up to it. We would loose 2-4% air from 7ish down to 3 or 4 and then if it sat in the mixer for 10-15min slowly turning it would come back up to 7%. Confused the heck out of me. This is probably why. I'd love to see more about vacuum stuff. Great info. Thank you.

A project I was apart of in 2018-2019 with CDOT submitted samples for this study, but we never really heard a follow-up to it all. Colorado revised the point of sampling from after pumping to before the pump a couple of years after though, so we assumed something significant was the result. It's awesome to finally know more about the research and the conclusion! Great video too!

I had a DOT job the spec’d 6% +/- 1.5 %. Got 7% before the pump, but after the pump it went down to 3.5%. They had me spike the air to a 12% so at the end of pump it would hit spec. I fought and fought until the threatened to reject the truck. Needless to say I had them sign off and make cylinders on both ends so they could see the weight difference. I actually sent them a video Tyler made a few years back on this topic.

Love ALL your videos man!!!!! I do QC in Colorado and your entertaining and informative videos help me so much!! Thank you

Fantastic work, I love the experimental and science-driven approach to presenting the information. I wish this was the norm. But of course, there is a considerable amount of work and knowledge that goes into making a video like that. Thanks to Tyler and the students for their hard work.

Amazing! We are having a panel discussion at our next local ACI chapter luncheon. Thank you!

No disrespect by saying bro, sorry Tyler, but yeah I'd love to discuss a few topics like this ,rebar , wire fiber ect

I have a diy that even you may not have heard of. Underground roof slab for storage room. One way design. 4x9 plywood form base. Set up to pour one 8 inch wide section at a time sleeves for distribution bars on the movable side. The idea is to pour and cover. Wait three days ,then install the next side form. Remove the side form from the poured section. Drop in the rebar cage for the next section and pour . Continue for 20 linear feet. All poured concrete remains covered with visqueen for 28 days. Am I right, or have you seen this before ?

Thank you, Dr. Ley, for this presentation.

Always use retarder and plasticizer in pump mix. Especially in hot weather . Always add 1-2 yards extra to prime pump lines . Then ensure pump has a place to clean out thoroughly. We had a Putzmeister 43 meter on NYC.

Bravo! This is valuable information! Thank you for the excellent content!

Interesting presentation. Thank you!

Hope you're doin' well professor! Can we have a two way slab design video?

Your presentation indicates that the spacing factor of normal temperature concrete recovers about 45 minutes after pumping. This suggests that while concrete sampled at the pump discharge may have a non-compliant air content/SAM number, cylinders cast from this sample of concrete should experience a recovery of dissolved air and have about the same spacing factor as cylinders cast from concrete sampled before pumping. When the concrete was sampled at various time intervals after pumping to check the SAM numbers, were cylinders cast and the spacing factor of the hardened concrete determined? If your premise is correct, the timing of casting the cylinders should not have a big influence on the results. If so, is the data available in one of your papers? My studies of annual LT results for a municipal QC program comprising dozens of samples indicate that there is often a characteristic relationship between hardened air content, spacing factor and specific surface, often unique to the concrete admixture package. I wonder if there may be something similar happening after pumping

This is AWESOME!!! Great info. Yes should always be at the truck. With this info, why is everyone wanting more air in the concrete if 4% is great. This would mean less cement( like everyone is wanting, green world) better breaks with less air. Easier to control then the 7% or 6% required.

Will you be publishing this? It would be amazing to have this as a simple reference when specifiers require sampling from the pump.

I want to experiment with making Roman Concrete. I am suprised there are so few videos that even talk about it. I only found one video where a guy made it but that was before the discovery of hot mixing. I would think the concrete industry and people like yourself would be all over the subject of concrete that has lasted over 2,000 years.

Hey bro I'm a concrete youtuber, I have some questions I'd like to ask u about on a stream! I been a fan for years and even shouted u out b4

It has been an argument for a very long time. POP is the pump!! We have no control over the concrete when it goes thru the pump!! What happens when the pump has a leak? Or the pump operator doesn't do a good job cleaning his pipe? So many factors involved.

Hello tyler, can you talk about concrete repairing techniques, cracks repairing and touch on the life time expectancy of a building?

So, if I wanted to make concrete with even better air entrainment and especially lots of tiny bubbles, could I compress air into the water at high pressure, then heat exchange the water down to about 40 degrees before I release the pressure and use that water to mix up the concrete? I'm thinking air dissolved into the water would tend to make really uniformly spaced tiny bubbles as it is released by the water. Is there any chemical that I could mix with the water that wouldn't mess with the performance of the concrete, but would make this technique work even better?

Use Sika Aer Solid for instance. What you put in you measure every where in the process and therefore you only need to measure once on the batching plant. It’s like really tiny ping-pong balls. The are specified for roadworks in Europe.

So how do we control this on site for the pour?