February 1986 Table of Contents

Features Using Tremie Concrete

All methods of placing concrete under water are designed to prevent cement washout and the consequent formation of weakly cemented sand and gravel pockets. Read more

Concrete Pavers Concrete Pavers

Concrete pavers offer a variety of patterns and colors that add to the character of any home, providing durable yet low maintenance surfaces. Read more

Features Pulse-Echo Testing

The decision to remove and replace faulty concrete can be a costly one. Read more

Features The Contractor Needs More Than Slump Control

The slump test is a commonly used tool for quality control of fresh concrete at the jobsite and for enforcement of specifications. It has limitations however, that should be recognized. Unfortunately, slump does not describe the properties of workability, pumpability, and finishability that are so important to the contractor. Read more

Features Construction Project Planning and Scheduling and the Microcomputer

Because accounting and estimating software programs follow most contractors' existing manual procedures, the contractor has to adjust his operating procedures only slightly to benefit from computerization in these areas. Read more

Features White Ferrocement Serves as Sculptor's Medium

Ferrocement was the medium chosen by sculptor Frederic A. Nassaux for creation of the white danseuse Isadora. This composite material gave him plasticity without the massive weight of conventionally cast concrete. Read more

Features Tilt-Up Goes Multistory

With a few notable exceptions, tilt-up construction methods have traditionally been applied to buildings of one or two stories. However, the economies that are possible using conventional tilt-up construction methods are realized to an even greater degree in multistory applications, where panel heights may exceed 50 feet. Read more

Features New Developments in Lift Slab Construction

Lift slab construction has become a basic method of economical concrete construction, especially for office buildings, apartments, parking garages, hotels and other structures characterized by repetitive framing from floor to floor. Read more

Features Building a Precast Prison

By fast-tracking precasting and erection operations, Forest City Dillon Precast Systems was able to complete the building frame for the Chilicothe Correctional Institution Number 2 in Ohio in about 8 months. Read more

Features Job Acceleration -- What Does It Really Cost?

Delays on a construction project can greatly increase the contractor's costs. And often the contractor incurs further expense as a result of forced acceleration made necessary by the delay. At other times, acceleration is requested by the owner when there was no original delay involved. In either case, legal action or arbitration may be needed if forced acceleration is necessary, the job is completed on time, and the owner refuses to pay for increased costs. To successfully present his case, the contractor must first prove his right to damages and must then substantiate increased costs. Read more

Features Insurance: Do You Really Have Enough Coverage?

Adequate insurance coverage is an important management problem for contractors. Part of the solution is to obtain a good understanding of the coverage provided by various types of policies and to become familiar with some of the grey areas that need to be covered at the time such policies are written. Read more

Features Sell Your Claims to the Owners

Once events occur that might lead to claims, both parties should immediately attempt resolution of the issues. Deferring claims normally results in larger claims eventually. Read more

Features Legal Remedies for Quantity Underruns and Overruns

When a ready mix concrete firm submits a bid to a contractor or owner, his per-cubic-yard bid or proposal may be based on someone else's estimate of the volume of work or materials required. Read more

Features Owning Your Equipment: the Costs

Determining the actual costs of owning and operating your equipment is one of a contractor's greatest challenges in bidding. Jobs must be bid with equipment costs in mind, and the items included and methods used must be acceptable in costing claims. There are several elements of ownership cost: Read more

Problem Clinic Cracking of New Topping

We contracted to remove and replace a cracked and broken topping in a 6 x 40-foot area of the second floor of a two-story concrete garage. The structural steel of this building, built about 50 years ago, is buried in the concrete. Although the owner thoug Read more

Problem Clinic Cracking in Floor Cast Over Plank

Last December we cast the first and second floors of a building by placing concrete 2 1/2 inches thick over precast plank. Late in April the owner reported that extensive random cracking has appeared on the first floor and a small amount on the second flo Read more

Problem Clinic Keeping Concrete Particles Out of Food

Our company has a room in which machines are located directly below the hoppers of some 15-foot-square reinforced concrete bins that hold raw popcorn. Sometime in the past the bins were sprayed on the inside with an epoxy coating. Now small rock-size chun Read more

Problem Clinic Expansive Cement Concrete Mix Too Stiff

We are replacing the deck of a 15-year-old parking garage one section at a time, using expansive cement concrete. The water-cement ratio is 0.40 in a mix containing 750 pounds of cement per cubic yard, and we are meeting the early strength requirement of Read more

Problem Clinic Entraining Air in Low-Slump Dense Concretes

It has been proposed that we try to provide good protection for the rebars in our city bridge decks by covering the decks with concrete toppings that have low permeability. Air-entrained mixes with slumps of 1 inch, made at very low water-cement ratios, h Read more

Problem Clinic Superplasticizer Trouble With Low-Sand Mix

This picture shows a foamy area that showed up on a 35-foot column after the forms were stripped. On close inspection you can see exposed aggregate, both fine and coarse, in the defective area. In some places you can even see exposed rebar. Read more

Problem Clinic Use Good Jointing Practices

Why does good concrete crack at random locations even though the sidewalk has been jointed? Read more

Close X