July 1988 Table of Contents

Features If It's Still Standing, It Can Be Repaired

Concrete repairs sometimes fail because bond between new and old concrete fails. Read more

Features Slabjacking Solutions for Settled Slabs

Concrete slab settlement causes problems. But slabjacking, properly done, solves the problems permanently. It's faster and much less costly to raise a concrete slab than to replace it. Read more

Features Structural Rehabilitation of Concrete Lighthouse

Brandywine Shoal Lighthouse stands 7 miles west of Cape May, New Jersey. It is the first reinforced concrete structure of its kind located on a submarine site in the continental United States. Read more

Features How to Build Concrete Parking Lots

Parking lots are a cost effective alternative to asphalt that saves owners money in lifetime costs. To encourage good construction of concrete parking lots, the American Concrete Institute (ACI) formed Committee 330, Parking Lots, in 1982. The committee's first document, "Guide for Design and Construction of Concrete Parking Lots," was published in December 1987. Read more

Features Unbonded Single Strand Post-Tensioning Tendon Detail

Single strand tendons offer an efficient, economical, and practical way of post-tensioning many types of building structures. Read more

Features Bonding New Concrete to Old

Bonding fresh, plastic concrete to old, hardened concrete increases the strength of the composite material. Bond is not, however, guaranteed. It must be ensured throughout proper surface preparation, material choice and use, and curing. Read more

Features Developing Construction Safety Awareness

Accidents in the construction industry cost $8.9 billion, or 6.5% of the total annual construction dollars. Read more

Features Concrete Jungle

Daily rainshowers, peat bogs, and heavy, wet clay didn't dampen efforts to create a 4.5-acre concrete tropical landscape in less than 7 months for a Puerto Rican hotel. Read more

Features Fragile Face-Lift

Salty sea air made the rebar corrode in decorative precast concrete balcony facings of an 18-story coastal condominium in La Jolla, California. Read more

Features Predicting Plastic Shrinkage Cracking in LMC Overlays

Plastic shrinkage cracking is a potential problem when latex modified concrete (LMC) is placed on a dry, windy day. Read more

Problem Clinic When to Grind a Defective Surface

Will it hurt to grind concrete the day after its placed? We're the general contractor for an office building project. We told the flatwork contractor to use a broom finish for a wide sidewalk around the building perimeter. He misunderstood and gave it a r Read more

Problem Clinic Elongated Slabs Are Likely to Crack

What's the maximum recommended length-to-width ratio for sections between joints in a slab on grade? The drawings for a job I'm building show some bays that are twice as long as they are wide. No wire mesh is called for in the 6-inch-thick slab. Read more

Problem Clinic Reduce Cover With Silica-Fume Concrete?

Is there any current practice or potential for reducing required concrete cover when silica-fume concrete is used? With its greatly reduced permeability, shouldn't you be able to get by with less clear cover? This would be especially helpful for reducing Read more

Problem Clinic Test for Presence of Fly Ash

Is there a test for determining whether or not fly ash has been used in concrete? If so, can the test show how much was used? Read more

Problem Clinic Computer-Aided Formwork Design

Our water treatment plant job has a specification provision that we must submit all formwork calculations for approval. Read more

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