Concrete Evaporation Rate Calc

Enter air temp, concrete temp, humidity, and wind — get the evaporation rate against the plastic-shrinkage limit and a countdown for every finishing gate.

PourClock is a concrete evaporation rate calculator and finish-window timer that runs entirely on the phone. The supplier's web calculator is dead in a no-signal building shell; this one never asks for a connection.

AT THE TRUCK
Punch in four field readings on a keypad sized for a gloved thumb: air temperature, concrete temperature, relative humidity, and wind speed. The app computes the evaporation rate using the nomograph method published in ACI 305R (the Menzel/NRMCA formula) and calls the verdict against the active limit — 0.20 lb/ft²/hr conventional, 0.13 for low-bleed SCM mixes. Over the limit, the dashboard says FOG NOW in numbers you can read from ten feet.

ON THE GANGBOX
Set the phone down and let the clock run the morning. Temperature drives the timeline — at 50°F you may wait two hours to trowel; at 90°F you may have 20 minutes. Low humidity plus wind plus heat is the worst combination: you can lose your finishing window before you realize it. PourClock arms audio and haptic alarms for placement, bleed watch, bull-float, wait-for-set, and trowel, plus a cold-joint cover countdown per lift. The alarms are backup to the finisher, never a replacement — bleed water is the gatekeeper, never finish over it, and the sheen and footprint checks on the surface always overrule the clock.

AFTER THE POUR
Export the pour record — field readings, computed rate, active limit, the call, and every gate time — as a PDF or CSV through Android share, ready for the GC's file when a hot-weather spec question or a plastic shrinkage cracking claim comes back months later.

PRICING, UP FRONT
Your first 3 full pours are free — full engine, alarms, presets, and export. After the trial, the fog call stays free and a license through Google Play Billing unlocks the full clock for unlimited pours. One avoided crazed-slab regrind pays for any plan.

WHAT IT NEVER DOES
- It never guesses weather from the phone. You enter field readings from the slab: no weather feed, no account, no ads, no backend, no internet permission.
- It does not declare a floor acceptable. The finisher's surface check and the third-party acceptance walk are the final authority.
- Units are locked once per job and echoed on every screen, so a °C reading never lands in a °F formula.

PourClock uses the evaporation-rate nomograph method published in ACI 305R. It is not affiliated with or endorsed by the American Concrete Institute.