Delivery Delay Mid-Pour Response

Purpose

The cold joint prevention HowTo in this library explains why a truck running more than 15 minutes behind its slot is the trigger point: past that, the leading edge is losing working time faster than dispatch can usually recover it. This procedure is what the crew leader actually does once that call comes in, not the mix-design margin that HowTo covers, but the real-time decision standing at an edge that is aging by the minute. Guess wrong here in either direction, hold too long hoping the truck shows up and the edge sets past consolidation, or declare a joint too early and throw away workable concrete and a clean bond, and the shop owns the outcome either way.

Scope

Covers the field response from the moment a scheduled truck is reported late through resumption or a planned stand-down, for flatwork, footings, and walls on residential and light commercial work.

It does not cover mix-design margin, retarder dosing, or the supply-rate math that prevents a delay in the first place, owned by the cold joint prevention HowTo; ticket acceptance or rejecting a load once it arrives, owned by the ready mix delivery SOP; or post-installed anchor sizing and embedment, owned by the post-installed adhesive anchor reference, which this procedure calls on rather than restates.

Roles and responsibilities

Procedure

1. Get the delay as a number, against the clock already running. The moment dispatch or a driver reports a truck behind schedule, get minutes late against the planned interval, not a general assurance, and record it against the elapsed time since the leading edge was placed. Acceptance: a specific delay figure logged with the current age of the placed edge. Wrong looks like acting on "should be here soon" with no number attached, which leaves the crew guessing at exactly the moment a guess is most expensive; stop rule, call dispatch back for a number before doing anything else. Hazard: none, a phone call.

2. Test the leading edge's actual condition, not just the delay figure. Probe the placed edge with a trowel or re-run the internal vibrator briefly at the very edge and read how it responds, since initial set is temperature-dependent and the same delay behaves differently on a cool morning than a hot afternoon. Acceptance: a stated result, the vibrator still reconsolidates the material and a trowel still penetrates it, or it does not. Wrong looks like judging purely off elapsed minutes without testing, which misses a hot-day edge that has already gone past workability well inside what felt like a safe window; stop rule, no decision on the delay until the edge itself is tested. Hazard: none directly, though the vibrator stays lifted by its shaft, never the cord, per the slab pour and finishing standard.

3. If the edge still passes, buy time without closing it off. Keep the edge lightly worked, protect it from evaporation per the hot weather pour standard's fogging and wind-screen technique without adding water, and hold every finisher off floating or troweling that edge, since a closed, finished surface has nothing plastic left for the next load to bond into. Acceptance: the edge still passes the step 2 test on any re-check, no crust visible, no finishing tools used on it yet. Wrong looks like a crew starting to float the edge to "get ahead" while still hoping the truck shows up soon, which finishes the exact surface the next load needs to still be open; stop rule, floating or troweling the leading edge does not start until either the next load is discharging against it or the joint call in step 4 has been made. Hazard: fogging equipment runs near powered tools, so cords stay clear of the wetted area on a GFCI-protected circuit.

4. Once the edge fails the test, declare the joint rather than keep waiting. The moment step 2's re-check fails, or the delay passes the 15 minute trigger the cold joint HowTo names and the edge is trending toward failing, stop hoping the next truck beats the clock and commit to a construction joint at the current edge. Acceptance: a stated joint decision with the time and the step 2 result that triggered it. Wrong looks like a crew holding out for "just a few more minutes" past a failed workability test, which is exactly how an unplanned cold joint gets poured over rather than prepared for; stop rule, a failed edge test ends the hold-and-wait path immediately, no exceptions for how close the truck sounds. Hazard: none at the decision itself, the next step carries it.

5. Prepare the edge as a real construction joint, sized for whichever state you caught it in. Where the edge is still plastic, insert dowels by hand while it will still accept them, spaced per the joint layout SOP's dowel schedule for this slab thickness; where it has already crusted or set, chip back to sound material and drill and epoxy-set dowels per the post-installed adhesive anchor reference, sized to the same schedule. Acceptance: dowels placed and, where drilled, embedded per the reference's stated values for that bar size and this thickness, with the face roughened. Wrong looks like butting the delayed load against an unprepared edge once it finally arrives, which produces exactly the disguised cold joint this whole procedure exists to avoid; stop rule, no discharge against the edge until the dowels are in and the face is roughened. Hazard: drilling into hardened concrete generates respirable crystalline silica, so it runs under the silica dust control SOP's water-fed control, and epoxy anchor adhesive carries its own skin and inhalation hazards per its SDS, so gloves and ventilation match the product before mixing it.

6. Resume against the joint, or stand the pour down. Once the delayed or replacement truck arrives, resume placement directly against the prepared joint; where the delay has grown long enough to threaten the rest of the day's schedule, weather, or crew hours, the PM calls a stand-down at the joint, barricades the completed work, and reschedules the remainder with written customer notice. Acceptance: either a logged resumption against the prepared joint, or a logged stand-down with a reschedule date and notice sent. Wrong looks like a crew deciding on its own to push through a shrinking daylight window rather than getting the PM's call; stop rule, the stand-down decision is the PM's, not the crew leader's, once the delay crosses that threshold. Hazard: an unfinished, barricaded slab overnight carries the same exposed-edge and impalement hazards named in step 5, so caps and barricades stay through any stand-down.

The record this produces

One delay-response record per occurrence. Fields: job and pour identifier, the reported delay in minutes, the leading edge's age at the time, each step 2 test result and its time, the joint declaration time, dowel type and embedment method with the reference values used, resumption or stand-down time, and any customer notice sent.

It sits with the delivery log for that pour. The PM reads it if a bond line shows up later exactly where a delay was logged, and the estimator reads delay records across a season, since a shop whose delays cluster around one plant or one time of day has a scheduling fix available that a single crew cannot supply on its own.

One pass, with a step that failed

An 18 by 32 foot driveway apron, 4 inch slab, ordered as two trucks of 4 cubic yards each off a planned rate that put the interval at 24 minutes. Truck 1 arrived on schedule and placement of the first half finished at the interval mark. Step 1 logged the call from dispatch: truck 2 running 35 minutes behind its scheduled slot, well past the 15 minute trigger.

Step 2 ran twice. At 15 minutes past the edge's placement, a vibrator check still showed the material reconsolidating cleanly, so step 3 held: the edge stayed lightly worked, fogged per the hot weather standard with no water added, and no finisher touched it with a float. At 35 minutes, when dispatch's call came in, the re-check failed: the vibrator no longer pulled the material back together and a trowel met refusal rather than penetration.

Step 4 declared the joint at that point, 35 minutes after the edge was placed. Step 5 found the edge had only a thin skin, about 1/8 inch, so the crew chipped that skin back to sound material along the joint line and drilled and epoxy-set dowels per the post-installed adhesive anchor reference for the bar size and slab thickness the joint layout SOP's dowel schedule calls for, roughening the face before capping the last hole.

Truck 2 arrived at the 52 minute mark. Step 6 resumed placement directly against the prepared joint, and finishing proceeded on the second half on its own schedule from there. Had the crew instead kept working the edge on hope through the full 52 minutes without the step 2 re-check, the joint decision would have been made by the concrete itself rather than by the crew, against a face nobody had chipped, roughened, or doweled, and indistinguishable at handover from a slab poured in one continuous placement.

When the delay does not resolve cleanly

The replacement truck is also going to blow the 90 minute discharge clock by the time it arrives: reject it per the ready mix delivery SOP rather than accepting a load that is itself now a supply problem layered on the first one. The delay is caused by a plant-side batching problem rather than traffic, and a second truck is likely to run late too: tell the PM before committing to a same-day resumption, since chasing one delayed load with another compounds the risk this procedure exists to manage. The site loses daylight or the weather turns before the joint is even prepared: get the exclusion zone and any exposed steel protected first, per the flash set and early stiffening response's step 5 pattern, then finish the joint prep once conditions allow. A customer or GC pushes to keep pouring past a failed step 2 test: the answer is the test result, not the schedule, and the shop does not place fresh concrete against an edge it has already confirmed cannot bond it.

References

• The cold joint prevention HowTo, in this library, for the supply-rate math and the 15 minute trigger this procedure operationalizes in the field.
• ASTM C403/C403M, time of setting of concrete mixtures by penetration resistance, for the underlying initial-set concept behind the step 2 workability test.
• The post-installed adhesive anchor reference, in this library, for dowel sizing and embedment when the edge has already hardened.
• 29 CFR 1926.1153, respirable crystalline silica in construction, for drilling into a hardened edge.
• See related: the ready mix delivery SOP, the hot weather pour standard, the joint layout and sawcut timing SOP, and the flash set or early stiffening mid-pour response.