{Question} I am in a dispute with my customer. He tells me that the concrete did not contain the right rock. I gave him what he always orders. He says the specification has a limit on iron oxide. Does it really say that?

{Answer} A big change occurred in ASTM C94, the standard specification for ready-mix concrete found in almost all commercial specifications. That change requires the purchaser to inform the producer of the specification. It seems obvious to me that this should be a normal part of the course of business, however frequently the ready-mix producer has a single page of section 03300 of the specification, or perhaps even just a verbal description.

The ready-mix producer agrees to perform his portion of the contract, specifically the delivery of ready-mix concrete, according to the specification. Most projects that go this way have few problems. However, for those projects which have problems, the lack of reading the specification, including the notes on the drawings, put the ready-mix producer in peril.

Recently, I have seen a couple of examples of this. In the project specification the course aggregate is required to “conform to ASTM C33.” Note that there is no description of exposure class for grade, such as 1S or 5S in the specification. This can lead to difficulties later, as in the case of concretes that are intended for architectural purposes, but are not specified that way.

Other issues that can arise in specification are the reference to ACI 301, the standard specification for concrete. This is often thought to protect the designer, however it too lacks specificity with respect to the coarse and fine aggregate quality requirements.

Inevitably what occurs is an iron oxide stain, or pop outs, or some other objectionable, in the eyes of the owner, performance of the concrete.

On another item the specification needs to be read in its entirety. If the specification says, “All coarse Aggregate shall conform to ASTM C## Class 5S,” and then, “The Los Angeles Abrasion loss shall be less than 10%,” the strictest requirement always applies. When the surface abrades due to softer aggregate than was specified, problems ensue.

Immediately the discussions of “bad concrete,” and “not acceptable concrete,” and “not the normal standard of local work” are brought up, and clearly the concrete supplier is to blame and will foot the bill for the repair. One should recall that it is a key aspect of contract law that you get what you specify, not what you want. However, it can be time-consuming and expensive to pursue one’s rights under the contract, and therefore the ready-mix producer should be very careful to commit to conforming to a specification which they may never have seen, let alone read and understood.

The next time you sign a purchase order, read the terms. You will see that you are bound as tightly to the specification as the sub or general contractor. A key part of risk management is to review the specification. If there are direct conflicts, such as a burnished finish on air-entrained concrete, bring these to the attention of the contracting party for clarification. Being smart after the fact doesn’t help.

Kevin MacDonald is president of Beton Consulting Engineers. Contact him at kmacdonald@betonconsultingeng.com or visit www.betonconsultingeng.com.