A common issue on construction sites is deciding whether to pour old concrete trucks or send them back. In the past, concrete contractors attempted to secretly use old trucks for pouring, but today we have a third-party testing company to test concrete batches. So, the problem is..........
When was a concrete truck considered too old to be poured?
Do you need to send it back?
The answer is yes or no.
Yes - According to ASTM C-94, concrete discharge must be completed within 90 minutes after mixing water with cement and aggregates.
No - ASTM C-94 also stipulates that if the slump meets the mix design specifications without adding water, these restrictions can be lifted.
Our suggestion:
In specific construction, planning and communication are crucial for the success of the project. Before conducting any large-scale or unique pouring, contractors, concrete suppliers, and pump operators should hold a pre pouring meeting to ensure successful and timely pouring.
At this meeting, various parties will discuss many issues, but an important scenario is how to handle when the concrete truck reaches 90 minutes. Each project, city, engineer, and general contractor is different. When problems arise, discussing ASTM and ACI standards will bring positive results.
