January 2004 Table of Contents

Features The Path to Take: Muskegon, Michigan

In western Michigan, approximately 25,000 square feet of decorative concrete was placed as the entrance to a lakefront development in Muskegon. More impressive than the amount of concrete, however, were the method and the time involved. Read more

Features Computers In Construction

Computers have pervaded our society, and it is time to consider how they can best serve the concrete construction business. Read more

Features Maturity and Strength

Concrete in a test cylinder and concrete in a structure seldom cure at exactly the same temperature. During cold weather, the structure may cure more slowly, or it could cure more quickly as cement hydration heats up the concrete in the forms. But since we don’t know the in-place strength, to be safe, we have to wait to be sure the concrete is up to strength before we strip forms, stress post-tensioning cables, or allow traffic onto a road surface. We need a reliable way to determine the actual strength of the concrete in the structure. That’s where the maturity test comes in. Read more

Features Marquette's No-Crack, No-Curl Floor

What Marquette University, Milwaukee, wanted for its new Al McGuire Center sounded simple enough—a 22,000-square-foot maple gym floor that would be flat and would not buckle and warp over time due to moisture problems. For Milwaukee's Opus North (specialists in design/build construction), the floor was a critical-path item on the construction schedule. Opus North wanted fast construction but without problems between the concrete and flooring contractors. In order to honor the schedule for the wood flooring installation, the moisture content in the concrete floor slab had to be low enough. Making all this happen would be a challenge involving good technology and attention to the details. Read more

Decorative Concrete Techniques for Chemically Staining Concrete

Chemical stains aren’t like paint. They don’t produce solid, even coloration. And there aren’t many colors available—only six or seven. Chemical stains produce translucent colors with somewhat unpredictable variation, but that’s why people are so interested in them. Read more

Problem Clinic Rain's Effect on Fresh Concrete

We had a concrete patio placed. About 3 hours after it was placed, it began to rain and continued to rain for 2 hours. Will that compromise the integrity of the concrete with respect to strength, durability, and so on, over the long term? Read more

Problem Clinic Horizontal Drilling

I have to drill a large number of 5/8" to 11/8" holes in reinforced concrete on vertical surfaces for embedding steel rods using epoxy. Many must be drilled above shoulder height, sometimes while on a ladder. It's very difficult and dangerous to drill the Read more

Problem Clinic Durability of Lightweight Concrete

I am designing a supported slab that will carry forklift traffic. I am planning to use lightweight concrete. What wearing surface would be appropriate with lightweight? Read more

Problem Clinic Normal Concrete Weight Loss

I am working on providing material for crane counterweights. What is considered a normal weight loss (in pounds per cubic foot) for concrete, from say its plastic weight to a normal exposure weight, after perhaps a month or two? My guess would be in the a Read more

Problem Clinic Fly Ash in Concrete Pavement

What are the effects of using fly ash in concrete pavements? Does it have an impact on abrasion resistance of the mix? Are case studies or field data available, especially where more than 30% fly ash was used in the mix? Read more

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