Grouting Training Q&A

Grouting Questions Received from Webinars

 

About time limit for grouting. When does this time begin? When you finish placing the tendons inside the element? or is it taken after tensioning? 

 

ACI Report 222.2 raised a concern over the use of water-soluble oil related to bond for corrosion protection of strand. What is the most common application of temporary corrosion protection of strand currently used?

 

At what point is the tendon tested with air? It seems it needs to be before the ‘concrete’ is placed correct?

 

Can you give a situation where it might actually be warranted to flush the grout out with water-e.g., when the density test at outlet shows there was significant water in the duct or other scenarios?

 

Confirm, the "grout pressure bleed" test is a field/site completed test? Or is this a laboratory test?

 

Could you please send me more information, details about grouting vertical tendons?

 

Do the grout discharge points always have to be above the duct level?  

 

Does it take longer time to install PL3 than the others?

 

Does the Contractor need to demonstrate they can kick in the backup grout plant up and pumping without exceeding 30 minutes?

 

Experience verification.  Would it be advisable for a worker to maintain a log detailing:

 

For an extreme climate grouting operation, if you must grout months after stressing, can you use vacuum in an effort to remove air (and possible moisture) from the tendons to minimize corrosion development?

 

How fast do you need to be mixing when you have grout in the second container ready to grout?

 

How is documentation handled when rust is observed on strands prior to installation? Shouldn't photos be taken of the degree of rust observed and the degree of cleaning made, documenting the coil number associated with the observed rust? And is the Contractor ultimately responsible for the removal of observed rust?  Who is responsible to ensure rust is removed prior installation?

 

I guess filter condition and changing should be covered in the ASTM Spec?

 

If during post grouting inspection, some vents are slightly low in grout, is it ok to add more grout?

 

IF ice is utilized during grouting, wouldn't it be important to make sure that the weight of ice needs to be subtracted from the amount of water that initially is removed so that the total weight of water comes out the same as needed for mixing?

 

If you have a tendon blockage what can you do to troubleshoot?

 

Is the pressure increased in flat horizontal ducts?

 

Is there a minimum length required for trumpets or is that determined by the design engineer during the design phase? Or are all trumpet lengths determined by the diameter of the anchor head diameter?

 

Is there a standard degree of pitting that would disqualify a tendon for use? What would you use to identify the level of pitting found in the field?

 

Is there a test owners can specify to check chloride content in pre-packaged grout?

 

Some anti-corrosion oils absolutely do affect bond strength.

 

To avoid excessive grouting pressure: What diameter of grout hoses is suitable? 

 

What action to be taken if grout leaks happen from a minor crack during grouting? Should grouting continue?

 

What can we do if we noticed air leak before grouting?

 

What if the duct separated during concrete placement?

 

What is meant by "Soft Grout"?

 

What is the average grout strength?

 

What is the best way to test the water temp during prod. grouting? What are acceptable sample points for sampling for water temp? 

 

What mitigation is recommended for the "cold joint" between lifts of grout, if any?

 

When do you perform the pressure bleed test?

 

When do you recommend doing the air testing of the ducts? 

 

When locking off the air flow for the air test, are you sealing the inlet valve on the duct side or just the input from the air compressor? If you are sealing the air flow input, where is the gauge placed to really check the air pressure change to identify leaks?

 

When running bleed test during production, what is the point if the results are not available until multiple tendons have been grouted?

 

When you tap in a new inlet, is it tapped when the grout is still liquid or after it's hardened? Put another way, are you tapping into flowable grout and continuing to pump from there, or are you tapping ahead of the hardened grout? (What happens to trapped air behind - between the tap and the hardened grout?)

 

When you try to fix a blockage duct and drill to install a new vent to re-establish one-way grouting, how do you make sure you don't damage the tendon? 

 

Where is the best place to satisfy the 90F as the discharge temp is typically hotter than at the mixer where the friction passing through the duct has not taken place, especially on long tendons?

 

Who do you report these data to?

 

Who/why would one go about rejecting a grouting team?

 

Will the strand supplier typically recommend the 'approved oil'?

 

Would you recommend me a document in which I can read more about thixotropic grout, its general composition, characteristics, etc.?