July 1997 Table of Contents

Features Alternatives to Using Type V cement

We're going to be placing concrete slabs on grade in an area where the water soluble sulfate content of the soil is 0.4% (severe exposure). Is the use of Type V cement mandatory for this exposure? Read more

Features Tilt-Up Concrete Makes Strides in the Building Market

Among the top building types -- pre-engineered metal, masonry, precast concrete and tilt-up concrete -- what is the best option for today's consumer, who demands products that are cheaper, faster and better? Recent studies show that the building industry is gravitating toward tilt-up construction due to recent advances and refinements in tilt-up methods and panel components. Although tilt-up construction is not yet the answer for all building needs, it certainly fares well in the following areas: speed and cost of construction, maintenance costs and long-term value, energy efficiency and ease of expansion, and architectural appeal. Read more

Features How to Plan a Large Tilt-Up Project

Implementing a bulletproof plan is critical to the success of a tilt-up project, especially on a large, fast-track job. The author, president of a successful tilt-up contracting firm in North Carolina, presents five essential steps to developing an effective plan. They include reviewing the structural drawings, preparing shop drawings and materials submittals, jobsite staging, planning crew size and sequencing, and planning tool and equipment needs. Read more

Features Concrete Courthouse Presents Shoring Challenges

Topped out in May 1997, the $97 million Charles Evans Whittaker U.S. Courthouse in Kansas City, Mo., is already being called one of the city's most impressive landmarks. The 587,000-square-foot C-shaped concrete-frame building was built using 20-inch-deep by 66-inch-wide pan forms, with joists and beams that clear span up to 50 feet. The structure required more than 4,500 tons of reinforcing steel and 46,000 cubic yards of concrete. Read more

Cover of Welded Wire Fabric in Slabs on Grade

Many design professionals choose not to use welded wire fabric in slabs or pavements because they believe the amount of cover can't be controlled. To address these concerns, research was conducted in 1996 to determine if WWF was at its correct location in a completed slab or pavement in which supports or a two-course concrete placement was specified. The results of the research show that the cover of WWF can be controlled within specification limits if adequate supports are provided. An effective way to determine the amount of cover is to use a portable battery-powered cover meter that induces a magnetic field into the concrete through a hand-held probe. Read more

Features The New and Improved Slab-on-Ground Design Manual

After a highly successful first run, the Post-Tensioning Institute's Design and Construction of Post-Tensioned Slabs-on-Ground has been extensively revised. Since the book's initial publication in 1980, it has been used by engineers and contractors to successfully design and construct hundreds of thousands of post-tensioned slabs on ground. The new 1996 edition reflects the industry's current knowledge of post-tensioned ground-supported slabs and is easier for design professionals to use. Read more

Jobsite Products The End of Cement Bag Massacres

A solution to hard-to-open, user-unfriendly cement bags has finally arrived. Ardex Inc., a manufacturer of specialty cements, has introduced a bag that can be opened and resealed easily thanks to a handy peel-off strip. Read more

Problem Clinic What's Type N Reinforcing Steel?

While inspecting reinforcing bars that were to be used on a project, I found several bundles designated N for type of steel. I know that the designations S, I, A and W indicate billet, rail, axle and low-alloy steels, respectively. But I can't find any AS Read more

Problem Clinic Source for Diammonium Citrate

I want to use diammonium citrate to remove discoloration from newly placed concrete. I've called chemical-supply houses and pharmacies, but no one seems to recognize the term. How do I find this material, and how much is it likely to cost? Read more

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