July 2001 Table of Contents

Features Making Information Work for You

A wise construction leader uses production information to determine a crew's efficiency. When properly educated on what performance numbers mean, even an hourly laborer can benefit by recognizing acceptable or nonacceptable work. Read more

Features What Is the Biggest Problem with Concrete Core Testing?

What alternative does the contractor have when concrete test cylinders show strengths are below specification? Is core testing required whenever this happens or are nondestructive tests like the rebound hammer sufficient? Who is responsible when the specified concrete strength is not met? Read more

Features Damage to Concrete Placed in Hot Weather

While durable concrete can be successfully placed in hot weather, increased rates of hydration and evaporation in fresh concrete and other problems can adversely affect concrete quality. Read more

Features Insulated Concrete Form Construction

Insulated concrete forms (ICF) are leading the way as a forming system and a construction technique for above grade homes. Polystyrene forms are held together by form ties and concrete is placed inside these forms. When the concrete cures, the forms remain in place to serve as insulation and attachment points for interior and exterior finishes. Because steel reinforcement is added, the finished product is substantially stronger and more energy-efficient than conventional wood frame structures. Read more

Features Slabjacking: Pump It Up

Slabjacking has many advantages over slab removal and replacement. Read more

Features Getting Connected

The Xtender, a new mechanical tension and compression rebar splicing system, finding widespread acceptance in the western United States, has both structural and field installation advantages. Bar end preparation is quick, simple, and economical and can be done either in the shop or in the field. Compared to lap splices, the Xtender reduces crane time and can result in fewer cranes being needed on the job. The relatively short couplers do not interfere with other reinforcing. Read more

Features Roden Crater

After 2 years and numerous changes, in January 1999 the final contract was signed for the first phase of artist James Turrell's largest work based on the changing experience of light. Read more

Concrete Basics Entrained Air in Concrete

Concrete always contains air bubbles. During concrete mixing and placement, these bubbles are first formed, then ruptured, merged, and floated out of the mix. But once the concrete has hardened, the bubbles that remain are fixed in place forming the air-void system in hardened concrete. Read more

Problem Clinic Flaking Driveway

I had a new concrete driveway poured in September of 2000. In January of 2001, I noticed that the very thin top layer is chipping and flaking. Read more

Problem Clinic Settling In

Before we purchased our home, part of the foundation under the house dropped approximately 4 inches. At that time the owner hired a contractor to fix the problem. By digging down alongside and putting jacks under the foundation, the contractor raised the Read more

Problem Clinic Soundproofing With Concrete

Do you have any information about concrete mixes for better soundproofing? The contractor wants to use the smallest amount of concrete between building floors but wants to achieve maximum soundproofing benefits. Read more

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