Why should we care about serviceability and durability?
There are generally three aspects to the performance of a structure. The first is structural. The structure needs to resist the gravitational, wind, and other loads to which it will […]
There are generally three aspects to the performance of a structure. The first is structural. The structure needs to resist the gravitational, wind, and other loads to which it will […]
ASTM C1778, “Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete,” can help you decide how best to mitigate expansions due to reactive aggregates. It covers both […]
Despite our need for durability and high performance, the most common design criterion for concrete is compressive strength. Usually we specify the 28-day strength, that is, the compressive strength after […]
When finishing air-entrained concrete, less is more. Hard-troweled surfaces and air-entrained concrete don’t mix. If you need to entrain air—that is, if the concrete will experience cycles of freezing and […]
Throughout my career, our industry has been pursuing performance specifications for concrete. That is, we want specifications for what the concrete must do, not what it must be. The sticking […]
Although engineers usually think of compressive strength as the most important property of concrete, concrete for slabs on ground is different. According to ACI PRC-302.1-15, for slabs on ground the […]
In Minnesota, Iowa, and South Dakota, we sometimes see aggregate popouts, particularly in concrete flatwork. Popouts are unsightly surface defects that may appear a few hours to a few weeks […]
The 2019 edition of the California Green Building Standards Code, also known as CALGreen, took effect at the beginning of this year. Its goals include: reducing greenhouse gas emissions from […]
Floor flatness and levelness matter in such applications as manufacturing facilities, big box stores, and warehouses. ACI PRC-117.1R-14 defines floor flatness (Ff) as “deviation of a surface from a plane” […]
Specifications for mass concrete require thermal control plans to minimize cracking. Traditionally, mass concrete meant dams. But other structures may be large enough—or have enough portland cement—to treat as mass […]