Latest.1280x720.jpg

Concrete trucks pouring


QUESTION: Recently we delivered a special mix to a foundation pour. The contractor had anticipated a fast placement and had ordered that all the trucks be on the job at the project's start. Just prior to starting the pour, the general contractor's safety officer shut the site down due to lightning concerns.

We had six trucks waiting on the jobsite. The storm lasted 90 minutes. Since the mix design was a special order, we couldn't redeploy the trucks to another job. Other than the thunderstorm, it was a perfect day for a pour. The ambient temperature was about 70º F and cloudy. The loads dried up a little, but the slump test result on the first load was within project specifications without retempering.

We were all set to start when the testing lab's field tech stopped the pour. He said the concrete was too old and he had no option but to reject all of the loads.

Was the testing lab's field rep correct in rejecting the loads? Was there an alternative?

ANSWER: The testing representative was correct regarding the time limit. But he was incorrect in suggesting there was no other way to address the issue.

ASTM C-94, Specification for Ready-Mixed Concrete, does place a time requirement on delivered concrete. The document states that discharge of the concrete shall be completed within 1 ½ hours after the introduction of the mixing water to the cement and aggregates, or the introduction of the cement to the aggregates. But the document clearly states these limitations can be waived by the purchaser if the concrete slump is such that the material can be placed without adding water.

To help prevent these types of disputes, the American Society of Concrete Contractors recently issued Position Statement #2, “Concrete Discharge Time Requirements.” This one-page document succinctly outlines the problem and possible solutions. Producers and contractors can use the statement in preconstruction meetings as a reference.



Share this article





Related Posts


Wheel Loader Wiki
Wheel Loader Wiki
Cone Crusher Supplier
Cone Crusher Supplier

Latest Posts
Asphalt manufacturing Process
Asphalt manufacturing…
Background Roofing shingles are made…
Used Snow Plows Maine
Used Snow Plows…
Snow just won’t fall exactly where we…
How to operate a Reach Truck?
How to operate…
The RTITB Reach Truck Operator training…
Wheel Loader Wiki
Wheel Loader…
DD-40 Heavy Duty Class Wheel Loader Machine…
Asphalt Paving Training
Asphalt Paving…
Caterpillar Paving Products is dedicated…
Search
Featured posts
  • How to operate a Reach Truck?
  • Wheel Loader Wiki
  • Cone Crusher Supplier
  • Walk behind Pallet Stacker
  • Truck mounted Jib cranes
  • Cat milling machine
  • Bruder Mack Granite Liebherr Crane Truck
  • Snow Removal supplies
  • Ford F150 Plow
Copyright © 2017 l www.mtnvalleyequip.com. All rights reserved.