# Concrete Batch Tickets and the Water–Cementitious Ratio

Reading a ready-mixed concrete batch ticket, checking time and drum revolutions, and working out the w/cm and the water that may still be added on site.

- Canonical URL: https://pavementinteractive.org/reference-desk/testing/cement-tests/concrete-batch-tickets-and-the-water-cementitious-ratio/
- Last updated: 2026-11-01
- Standards: AASHTO M 157, ASTM C94

Every load of [ready-mixed concrete](https://pavementinteractive.org/glossary/ready-mixed-concrete/) arrives with a delivery ticket. For the inspector it is a record of what is in the truck and when it was batched, and it is the only way to know how much water the concrete already contains. The ready-mixed concrete specification (AASHTO M 157, ASTM C94) lists what a ticket must show and sets limits on delivery time and site water (Taylor et al., 2019[^1]).

## What the Ticket Shows

A ticket normally shows at least:

- the plant, ticket number, date and truck number;
- the purchaser, the job and the mix designation or class;
- the volume of concrete in the load;
- the time of batching, or of first contact between cement and water; and
- the counter reading of the drum revolutions when water was first added.

Many agencies require more: the actual batched masses of cement, supplementary cementitious materials, each aggregate (with its moisture content), water and each admixture, and the water withheld at the plant that may be added on site. Electronic tickets increasingly carry all of this automatically (Taylor et al., 2019[^1]).

## Time and Revolutions

Concrete begins to stiffen once cement meets water, and continued mixing grinds the aggregate and drives off air. ASTM C94 therefore requires discharge to be completed within 90 minutes of introducing water to the cement, or before the drum has turned 300 revolutions, whichever comes first, unless the purchaser waives the limit. Hot weather, set-retarding admixtures and agency rules can shorten or lengthen this.

## The Water–Cementitious Ratio

The [water–cementitious materials ratio](https://pavementinteractive.org/glossary/water-cementitious-materials-ratio-wcm/) (w/cm) is the mass of water in the mix divided by the mass of all cementitious materials: portland cement plus fly ash, slag cement, silica fume and other [pozzolans](https://pavementinteractive.org/glossary/pozzolan/). It is the single strongest control on strength and permeability, so specifications set a maximum. Adding water raises the w/cm; it improves workability but lowers strength and durability (see [PCC Mix Design Fundamentals](https://pavementinteractive.org/reference-desk/design/mix-design/pcc-mix-design-fundamentals/)).

$$w/cm = \frac{W_{batch} + W_{free} + W_{site}}{C + SCM}$$

where:

- $$W_{batch}$$ = water batched at the plant, including ice and wash water left in the drum
- $$W_{free}$$ = free water carried in on the aggregates: moisture above the saturated surface-dry condition
- $$W_{site}$$ = water added at the site
- $$C + SCM$$ = mass of portland cement plus supplementary cementitious materials

The free water on the aggregates is easy to miss. A ticket that shows aggregate masses "wet" with moisture percentages lets you work it out: for each aggregate, the free water is its oven-dry mass times the difference between its moisture content and its absorption. Water in liquid admixtures is usually small and is often ignored; some agencies count it.

## Water Still Allowed

Before water is added on site, work out how much the mix can take:

$$W_{allowed} = (w/cm)_{max}\,(C + SCM) - (W_{batch} + W_{free})$$

C94 allows water to be added once on arrival, if the slump is below the specified value, provided the maximum w/cm is not exceeded and the water is mixed in with at least 30 more drum revolutions at mixing speed. Water added later in the discharge, or beyond what the ticket allows, makes the load nonconforming. Every addition should be recorded on the ticket with the amount, the time and who authorized it.

## A Worked Example

This example uses made-up numbers. A 7.0 m³ load with a maximum w/cm of 0.45 has these batched masses:

| Item | Value |
|---|---|
| Cement | 1,960 kg |
| Fly ash | 490 kg |
| Water batched | 860 kg |
| Fine aggregate, wet | 5,400 kg at 4.5% moisture, 1.0% absorption |
| Coarse aggregate, wet | 7,700 kg at 1.2% moisture, 0.6% absorption |

Free water on the fine aggregate: the oven-dry mass is 5,400 ÷ 1.045 = 5,167 kg, so the free water is 5,167 × (0.045 − 0.010) = 181 kg. On the coarse aggregate: 7,700 ÷ 1.012 = 7,609 kg, and 7,609 × (0.012 − 0.006) = 46 kg.

- Total water so far = 860 + 181 + 46 = 1,087 kg
- Cementitious = 1,960 + 490 = 2,450 kg
- w/cm = 1,087 ÷ 2,450 = 0.444
- Water still allowed = 0.45 × 2,450 − 1,087 = 15.5 kg, about 15 L for the whole load

In this case almost no water can be added. If the concrete is too stiff to place, the remedy is a water-reducing admixture (if the mix design allows it), not water.

Calculator: Batch ticket water–cementitious ratio — https://pavementinteractive.org/tools/concrete-batch-water/

## Standard Specifications

- AASHTO M 157, ASTM C94: Ready-mixed concrete

## Sources

[^1]: Taylor, P.; Van Dam, T.; Sutter, L. and Fick, G. (2019). Integrated Materials and Construction Practices for Concrete Pavement: A State-of-the-Practice Manual, Second Edition. National Concrete Pavement Technology Center, Iowa State University, for the Federal Highway Administration. Ames, IA. https://intrans.iastate.edu/app/uploads/2019/05/IMCP_manual.pdf