Quick Set Concrete Curing - Vehicular Traffic

[CBSE]

I'm specifying a 3-day mix for quick set concrete for a mat foundation in a log handling equipment yard. How soon is too soon to let loaders drive over the concrete after it is poured? I've been trying to find some guidance on this in my concrete manuals and must be looking over it.

Thanks

 

[Gumpmaster]

Try contacting one of the admixture companies for mix and loading recommendations. I talked with one of the BASF reps and they had a CALTRANS paving project that was placed overnight and loaded the next morning. It's a pretty juiced up mix, but they should be able to give you something more sedate that would meet your needs (or at least lead you in the right direction).

 

[SlideRuleEra]

There are lot of variable in concrete placement. The conservative approach is to have a qualified testing lab make concrete cylinders, test them daily, when the concrete reaches the foundation's DESIGN strength it is ready for traffic. Note that the concrete mix design strength could be higher than the foundation design strength.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[CBSE]

Thanks. I will see what I can dig up from the admixture companies. There has to be some pretty good data out there.

 

[Ingenuity]

We recently used a high-early strength concrete that our concrete supplier/batch plant 'designed' with the state DoT for bus stops. 7000 psi, with MIN 3000 psi in 24 hours. It actually achieved about 5,000 psi in less than 24 hours.

Course aggregate 3/4": 1800 lb
Fine aggregate: 1200 lb
Cement (type I/II): 900 lb
Water; 267 lb

Then it was juiced up with Grace Daratard-HC, Sika CNI, and BASF Glenium NS. It also had a few pounds of polypropylene fibres too.

It was a nice workable and pumpable mix. 4"+ slump. No entrained air.

Alternatively, on state highways bridges where deteriorated decks are replaced/repaired it is common for volumetric mixers to produce quick-set concrete using 'Rapid Set' cement from CTS in California. They have a DoT mix too. Open to traffic in less than 4 hours.

 

[cvg]

I would hesitate to "design the mix" myself. Call a local supplier and ask them for a recommended mix design with test results. They will be able to supply the appropriate admixtures. If you want real time data on the curing and strength of the foundation, install maturity meters and monitor the structure.

http://www.fhwa.dot.gov/publications/focus/02oct/01.cfm