January 1999 Table of Contents

Features A Winning Strategy for Fmin Floors

Narrow-strip concrete placements are the industry standard for narrow-aisle, defined-traffic warehouse slabs. To meet the tight flatness tolerances, usually Fmin 50 to 100, contractors perform narrow-strip construction by setting edge forms 14 to 20 feet apart and striking off the concrete with a vibratory truss screed. Read more

Features Effect of Water-Vapor Emissions on Floor-Covering Adhesives

"To stay on schedule, especially for fast-track projects, general contractors may be tempted to have floor coverings installed on concrete slabs regardless of the water-vapor emission rate of the slab. But before assuming responsibility for floor-covering performance, they should assess the probability of distress, which may include loss of adhesion between the covering and the concrete." Read more

Features Cellular Concrete to the Rescue

Composed of cement, water and small, discrete air cells, cellular concrete is a lightweight material that solves many heavy-duty construction problems. Used beneath roadways, bridge ramps, buildings and other structures, it reduces soil loading while adding compressive and shear strength. Contractors and engineers also use the material as backfill for tunnels, waterlines and sewers, to provide shock absorption in earthquake zones, to fill voids in silos and abandoned mines, to reduce hydrostatic pressure on walls, and for a myriad of other uses. Read more

Features On Firm Ground

Proper design and execution can make compaction grouting a reliable method for densifying loose soils and raising settled structures. Read more

Features A System for Building Sloped Concrete Roofs

The residential roofing market may soon change due to the ingenuity of architect Jose Henriquez and engineer Francisco Bermudez, who have developed a method of forming and building sloping roofs of reinforced concrete that uses commonly available construction materials and methods. Read more

Features Ten Ways to Cut Workers' Compensation Costs

Because a construction site is a hazardous place, your business can be hit hard with the many direct and indirect costs of nonfatal accidents and injuries including medical expenses, lost productivity, delays and disruptions to work, and administrative costs. Read more

Features Is It Time to Lift?

Before erecting tilt-up concrete panels, you must allow them to gain enough strength to withstand lifting stresses. Read more

Features Can the Millennium Bug Bite Your Business?

Imagine you were suddenly unable to retrieve your accounts-receivable records, or your project-management software lost track of all activities scheduled for completion early next year. Read more

Features A Positive Image Always Pays Off

Everybody and everything that represents your business creates an image and promotes an identity. It's up to you to decide if this company image turns out to be positive or negative, says the author, the president of a successful concrete construction company located in a Chicago suburb. Read more

Products Solving Problems Concrete Warehouse Requires No Heating

Though built near Chicago, where temperatures can plummet below zero in the winter and exceed 100° F in the summer, the 430,000-square-foot warehouse of Roman Inc. has no heating or air conditioning units. Yet the temperature in the warehouse stays about Read more

Problem Clinic Limit on Floor-Pour Size

We are placing a 4-inch-thick concrete floor for a 93,000-square-foot department store, but the architect has limited the size of each pour to 2,160 square feet to prevent premature shrinkage cracks. This limitation will severely cut our productivity and Read more

Problem Clinic Thermal Expansion and Contraction of Slabs on Grade

What is the rate of expansion and contraction for a concrete slab on grade due to temperature changes, and how much movement can be expected because of temperature change? Read more

Problem Clinic Is Hooking an Effective Way to Position Welded Wire Fabric?

We're placing a concrete slab on metal decking, and the plans require welded wire fabric to be supported by chairs. Because the chairs are likely to be dislodged by workers during placement, we're trying to convince the designer that we can pull the fabri Read more

Problem Clinic Will PVC React Chemically with Concrete?

We want to embed rigid polyvinyl-chloride pipe in concrete to allow drainage under a golf-cart path. The engineer won't allow this because chemicals in the concrete might attack the PVC. I know PVC has been widely used in this sort of application, but I'm Read more

Problem Clinic Water-Vapor Emissions and Room Relative Humidity

We build the concrete floor for a building occupied by a tenant who requires tight control of temperature and relative humidity in the work area. The tenant must maintain a relative humidity of 30% to 50% at a temperature of 68° F. But even though HVAC eq Read more

Problem Clinic Composites: Coming on Strong

A few years ago, the use of composites, or fiber-reinforced polymers, to strengthen concrete structures was only the subject of research in the United States. Read more

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