January 1998 Table of Contents

Features Rubber Mixer Liners

As environmental legislation becomes increasingly tighter, rubber mixer liners may be part of the solution. Rubber liners reduce maintenance cost, last three to five times longer than manganese steel and reduce noise by as much as 50%. The biggest saving, however, comes from not having to strip down mixers so frequently at the end of the day's production. Read more

Features Concrete Does Justice to Orlando Courthouse

Orlando's Orange County Courthouse uses concrete in almost all its variations: cast-in-place, precast, prestressed and post-tensioned. The building's 52 courtrooms required floor-to-floor heights of 16 feet, making the 24-story, 416-foot high-rise almost as tall as a typical 40-story building. Moreover, to provide the unobstructed views required in the courtrooms, floors had to span up to 49 feet. Such large floor-to-floor and column-to-column spacings obviously could result in a less-rigid frame, one more susceptible to the hurricane winds that all buildings in Orlando must be designed to resist. Read more

Features Diagnosing Slab Delaminations

This article, the first in a series on delamination of troweled concrete surfaces, discusses how bleeding, surface setting and delamination are interrelated. Delaminations are separations in a slab, parallel to and generally near the upper surface. On floors, they're caused by a buildup of water and air beneath a dense layer of surface mortar. Because the water and air create a weakened zone, traffic causes the surface layer to break away from the base concrete. Read more

Features Marketing Your Construction Services on the Web

A Web site can be a high-powered marketing tool if you include the right elements. Anyone with Internet access—including homeowners, general contractors, designers, government agencies and even prospective employees—can view your message. Also, your message is available round-the-clock and can be changed or updated at any time. Read more

Features Increasing Your Sales to Commercial General Contractors

Proper procedures, professionalism and attention to quality control and safety are all qualities commercial general contractors look for when choosing subcontractors. The author, a full-time commercial construction estimator and project manager for a Midwest general contractor, offers tips on how concrete subcontractors can become more competitive when low bids and a good reputation don't attract enough work. He explains how to make your presence known, increase your chances of getting jobs, and prepare a professional written proposal. Read more

Features Key Word: Concrete

Search engines are among the most popular sites on the World Wide Web, and most can be accessed free of charge. If used properly, they can link you to the information you need in minutes. Each engine--and there are many of them, even some specifically for the construction industry--categorizes information in a unique manner and searches the Web differently. Read more

Features No Texas Tall Tale

Despite tough obstacles, a construction team achieved remarkable F-numbers during the placement of a 26,000-square-foot concrete floor for a Texas arena. Challenges included: Read more

Features Finding the Best Spot for a Boom Pump

Finding the spot on the jobsite where the pump truck operates most efficiently takes a highway designer's eye for traffic flow, a pump operator's knowledge of how to unfold the boom and a negotiator's talent for resolving disputes. Read more

Features How to Get Paid Faster

Collecting the money owed to you by customers takes time, organization and effort. You can encourage fast payment, however, by treating customers firmly yet fairly and adhering to the following three rules: Read more

Features Safety Checklist for Tilt-Up Construction

When handling heavy tilt-up panels, crews need to take special safety precautions to prevent accidents. Some of these precautions need to be taken even before panel construction begins. Read more

Problem Clinic Thin, Unbonded Topping Over Plywood?

The plywood diaphragms under the floor of an unreinforced masonry building are warped, producing an uneven floor surface. I want to place a 3-to-4-inch-thick concrete topping to improve floor flatness, but a bonded topping would stiffen the diaphragms and Read more

Problem Clinic How Soon Can Grade-Beam Forms Be Stripped?

The concrete subcontractor on our job is placing grade beams that are 8 inches wide and 40 inches deep. A nonchloride accelerator has been added to the mix, and the subcontractor wants to strip the forms four hours after concrete placement so workers can Read more

Problem Clinic Causes for Corner Cracking

In December 1996 we placed a floor slab for a manufacturing plant, and a year later we were called back by the owner because one section had cracked badly. Read more

Problem Clinic Sawcutting an Existing Structural Slab

We have to cut a 2x2-foot opening in an existing elevated reinforced-concrete slab. An engineer has approved the location of the opening, but we're trying to decide the best way to cut it. In the past we've drilled core holes at the four corners of an ope Read more

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