How the Pour Schedule Is Built
A pour runs on two clocks: how fast your crew places concrete, and how long each truck's load stays good. The calculator tracks both for every truck.
1
Split Into Loads
Divide the order by the truck load size. 12 cubic yards on 10 yard trucks is one full load and one 2 yard load.
2
Time Each Load
Multiply load size by minutes per cubic yard. At 20 yd³ per hour, that is 3 minutes per yard, so 30 minutes for 10 yards.
3
Place Trucks
Each truck starts when it arrives or when the crew finishes the previous truck, whichever is later. The gap is waiting time.
4
Check the Limits
Add haul, wait, and unloading minutes for each load and compare with the discharge limit. Minutes past the unloading allowance are standby.
Discharge Time Rules Compared
The old 90-minute rule changed in 2021, but many job specifications still use it. Read your delivery ticket and your project specs for the limit that applies.
| Source |
Time Limit |
Drum Revolutions |
Notes |
| ASTM C94, older editions | 1-1/2 hours | 300 | Whichever comes first, after water meets cement and aggregate |
| ASTM C94, 2021 and later | Set by purchaser or producer | Set by purchaser or producer | Stated on the delivery ticket |
| State healthcare facilities policy (Oct 2025) | 1-1/2 hours | 300 (no more than 100 mixing) | Concrete under 90°F; cannot be waived by producer or purchaser |
| County construction spec example | 90 minutes | 300 | Water may be added once to reach slump, within the specified water-cement ratio |
Sources: ASTM C94 text, an ACI abstract on the 2021 change, a California HCAI policy notice, and an Elbert County, Colorado specification. Specifiers set the limit that applies to your job.
Use the concrete slump chart to check workability, and do not add water after discharge begins.
Why a Pour Is a Race Against the Clock
Concrete starts to set from the moment water meets cement. Every minute in the truck and on the ground uses up time you need for placing and finishing.
That makes crew speed the main variable. If the crew places concrete slower than trucks arrive, trucks queue, loads age, and standby charges start.
If trucks arrive more slowly than the crew works, the crew idles and the fresh edge of the pour can start to set before the next load arrives. This is how cold joints form.
Start from the volume. The concrete cubic yard calculator and concrete slab calculator give the order size, and the ready-mix truck calculator plans the loads.
Truck sizes differ by configuration and weight law. See the ready-mix concrete truck load chart for typical capacities, and the guide to pouring a concrete slab for the full sequence.
Minutes to Place One Truck Load
Find your crew's rate to see how long one 10 cubic yard load takes and whether it fits a 90 minute limit after a 30 minute haul.
| Placing Rate |
Minutes per yd³ |
Minutes to Place 10 yd³ |
Total With 30 min Haul |
Within 90 min? |
| 8 yd³/hr | 7.5 | 75 | 105 | No |
| 10 yd³/hr | 6.0 | 60 | 90 | Exactly at the limit |
| 15 yd³/hr | 4.0 | 40 | 70 | Yes |
| 20 yd³/hr | 3.0 | 30 | 60 | Yes |
| 30 yd³/hr | 2.0 | 20 | 50 | Yes |
Calculated as 60 ÷ rate × 10 yd³. Assumes the truck starts unloading on arrival with no wait. Your delivery ticket sets the actual limit.
If your rate is near the top of this table, order smaller loads or add placing capacity before the day of the pour.
Troubleshooting Sample Pours
These sample calculations show what goes wrong in a pour and how the schedule exposes it. They are illustrations, not documented projects.
✅ A Pour That Runs Smoothly
Order: 12 yd³ on 10 yd³ trucks
Crew rate: 20 yd³/hr (3 min per yd³)
Timing: 15 min setup, 30 min haul, 120 min finishing
Loads: 10 yd³ and 2 yd³
Truck 1: arrives at 15 min, unloads 30 min, ends at 45
Truck 2: arrives at 45, unloads 6 min, ends at 51
Pour: 36 min; total with setup and finishing 171 min
Truck age at end: 60 and 36 min, within 90
Starting at 7:00 AM, the crew is done at 9:51 AM. No standby: 30 min unloading is under the 50 min allowance at 5 min per yard.
⚠️ Trucks Arrive Faster Than the Crew
Order: 30 yd³ on 10 yd³ trucks
Crew rate: 8 yd³/hr (7.5 min per yd³)
Spacing: supplier sends a truck every 30 min
Per load: 75 min to place 10 yd³
Truck 2: arrives at 45, waits until 90 (45 min)
Truck 3: arrives at 75, waits until 165 (90 min)
Age at end: 105, 150, and 195 min against a 90 min limit
Standby: on-site minutes over the 50 min allowance add up
Even with perfect spacing, a 75 min unload plus 30 min haul is 105 min. The fix is smaller loads, more crew, or a pump.
🔧 Fixing It With Smaller Loads
Order: 30 yd³ in 6 yd³ loads
Crew rate: 8 yd³/hr (7.5 min per yd³)
Spacing: 45 min, matching the crew
Loads: 5 loads of 6 yd³
Per load: 6 × 7.5 = 45 min to place
Age at end: 30 haul + 45 unload = 75 min, within 90
Standby: 45 min unloading is over the 30 min allowance at 5 min per yard
Each truck now clears the time limit, but a slow crew still runs past the unloading allowance on every load. A pump or a bigger crew fixes the root cause.
Trucks, Standby, and the Finishing Window
🚛
Truck Spacing
Space trucks about as far apart as the crew needs to place one load. The ready-mix truck calculator and load chart show typical sizes of 9 to 11 cubic yards.
⏳
Standby Charges
Suppliers commonly allow about 5 to 7 minutes per cubic yard, then bill by the minute. Rates and rules vary, so get them in writing. See the concrete pour cost calculator.
🧽
Finishing Window
Per ACI, finishing begins when bleeding has stopped and the surface has stiffened, which typically coincides with initial set. Finish before final set.
After the pour, curing runs for days, not hours. See the concrete curing and drying time guide for the schedule that follows.
For a multi-day job, fit this pour into the plan with the project duration calculator.
Sources and Method
- ACI, "90-Minute Rule" for Ready Mixed Concrete (ASTM C94 replaced the default 90-minute rule in the 2021 edition with a time limit set between purchaser and producer): concrete.org
- California HCAI PIN 82, Ready Mix Concrete Placement Times (1-1/2 hours and 300 drum revolutions, 90°F, ASTM C94/C94M-24d sections 6.1.9 and 6.1.10): hcai.ca.gov
- Elbert County, Colorado, Section 800 Concrete Mix Design and Construction (discharge within 90 minutes or 300 revolutions; ASTM C94 water addition): elbertcounty-co.gov
- ASTM C94/C94M, Standard Specification for Ready-Mixed Concrete (earlier text on 1-1/2 hours and 300 revolutions): C94 copy
- ACI, When can the finishing procedure be started? (ACI 302.1R-15, finishing after bleeding stops and before final set): concrete.org
- Reported on-site unloading allowance of 5 to 7 minutes per cubic yard and standby rates, from supplier-based summaries (secondary): calculatingconcrete.com, and 5 to 10 minutes per yard: allconcretecalculator.com
- Typical truck sizes of 9 to 11 cubic yards, from this site's own chart: ready-mix concrete truck load chart
Placing minutes = cubic yards × minutes per cubic yard. Truck age at the end of discharge = haul minutes + waiting minutes + unloading minutes. Standby minutes = on-site minutes minus the unloading allowance. Setup, haul, and finishing defaults are planning values you can change.
Last reviewed: November 2026. Reviewed by site author.
⚠️ Disclaimer
This calculator provides estimates for planning purposes. For permitted structural work, foundations, multi-story construction, retaining walls over 4 feet, and commercial projects, calculations must be verified by a licensed structural engineer per IBC 2024 §1604. ConcreteCalculate.com is not liable for structural decisions made from these estimates.
Time limits, unloading allowances, and standby rates depend on your supplier, delivery ticket, and project specifications. Confirm them before the pour.
Calculations run entirely in your browser. No project data is stored or transmitted to any server beyond the calculation request itself.
