June 1998 Table of Contents

Features Making Beautiful Concrete

Karlson Forming Specialties, Amery, Wis., sells and rents a range of forming products, including form liners and rustication (recess) strips of polystyrene, polyurethane and polyethylene. Having a strong sense of forming know-how, owner Larry Karlson goes beyond just supplying forming products; he also helps contractors learn how to use these products properly and cost-effectively. He even works with architects during the design phase to show how the form liner products can contribute to project aesthetics. Read more

Features Preparing Surfaces for Coatings

When coatings applied to concrete surfaces fail, the cause usually is inadequate surface preparation. For a coating to bond properly, the concrete surface must be sound, clean, dry and free from surface defects. The surface also should be rough enough to establish a good mechanical bond. If the surface is not properly prepared, the coating is likely to separate from the concrete, wasting both time and money. Read more

Features One-of-a-Kind Concrete Resurfacing

How would you like to start a concrete business that requires a creative mind rather than a strong back? Stuart Holland, owner of Pacific Coast Paving, Medicine Hat, Alberta, Canada, started such a business, and it's been so successful that he's now demonstrating his creative techniques to other contractors throughout the United States and Canada. Read more

Features Exeter Library Receives AIA 25-Year Award

Commissioned in 1965, designed between 1966 and 1968 and completed in late 1971, the Phillips Exeter Academy Library has received the 1997 American Institute of Architects' 25-year award. Renowned architect Louis I. Kahn designed the structure's dramatic architectural-concrete interior. The inner shell of concrete forms a great central hall that rises six floors through the core of the building. Large circular openings in this core allow a glimpse of book stacks on the cantilevered balconies that make up the second concrete layer. The library's exterior shell, made of load-bearing brick masonry to harmonize with other campus buildings, is a series of arcades housing reading and study areas. The building's post-tensioned concrete frame features two deep concrete beams extending diagonally across the top of the atrium and intersecting at its center. Although the beams are 18 inches thick, 16 feet deep and contain 87 tons of concrete, their structural function is relatively limited. The chief purpose of the beams is visual: They act as a baffle to screen and diffuse light entering through clerestory windows on the sides of the central hall. Read more

Features Building a Decorative Retaining Wall

The author, a Pennsylvania contractor, describes how he used stenciled precast-concrete panels, set in a framework of steel, to create a striking retaining wall for his home. Because the reveal of the wall is only 2 ½ feet tall, the majority of the wall is below finished grade. To ensure against frost heave, he designed a "floating" concrete wall that could be built at a reasonable cost, regardless of climate. The wall system consists of precast-concrete panels set in a framework of steel H-sections. The panels, which are stenciled with a brick pattern and colored with a terra-cotta dry shake, create a striking contrast with the steel. Wood fencing provides privacy and additional contrast. Read more

Features How Clean Must Rebar Be?

Form-release agents, bond breakers and cement splatter sometimes contaminate reinforcing steel before concrete is placed. However ACI 301-96, "Standard Specifications for Structural Concrete," says: "When concrete is placed, all reinforcement shall be free of materials deleterious to bond." Inspectors often cite this sentence when requiring contractors to remove form-release or bond-breaker overspray and cement splatter from contaminated rebar. But is this work really necessary? Read more

Problem Clinic When Exterior Slabs Crack, Won't Reinforcing Steel Corrode?

Why would you put reinforcing steel in sidewalks, driveways or other exterior flatwork where cracking is likely to occur? Won't the cracks expose the reinforcing steel and increase the probability of corrosion? Read more

Problem Clinic Source for Concrete Engraving Equipment

I attended a home-improvement exposition where I saw a demonstration of a piece of equipment that can engrave brick, cobblestone or other designs in existing concrete sidewalks and driveways. I asked who made the machine but couldn't get an answer. Can yo Read more

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