COST (Concrete Optimization Software Tool) is an online design/analysis system to assist concrete producers, engineers and researchers in determining optimal mixture proportions for concrete.

With appropriate input from the user, COST uses statistical experiment design (DEX) principles to generate a set of trial batches (an experimental plan). The trial batches, which consist of batching, mixing, fabricating specimens, and performing necessary tests, are run by the user. The test results (data) can then be entered into COST for analysis and optimization.

Cost uses appropriate statistical analyses, both graphical and numerical, to assist the user in determining optimal mixture proportions to meet the particular project requirements.

There are two likely scenarios in which COST would be used:

- The first (and probably most common) would be to proportion a concrete
mixture to meet a set of performance criteria while minimizing the
cost of the mixture.
- Another possible objective is to maximize or minimize one or more responses (for instance, to achieve the highest possible strength).

COST requires the following input:

- One to five
**performance criteria**(e.g., slump, 28-day strength, etc.) and specification requirements for each performance criterion (e.g., minimum strength, allowable slump range, etc.) - Two to five
**mixture components**and lower and upper limits on each component's proportions. **Material properties**needed to determine mixture proportions and costs (specific gravities, absorption, cost, etc.)

Disclaimer: Neither the National Institute of Standards and Technology nor the Federal Highway Administration shall be liable for any damage that may result from using the COST system. NIST and the FHWA have made their best efforts to assure that the information provided by the COST is correct and accurate. However, they make no warranties to this effect.