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Tilt-up walls are cast at the job-site using locally produced ready mixed concrete; the building slab on grade typically serves as the wall panel's primary form surface.
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ASTM metric standards for billet-steel bars first appeared in ASTM A 615 in 1979.
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Pride in workmanship from dedicated, knowledgeable people are the keys to achieving outstanding results in concrete paving, according to this year's winners and runners-up in the fifth annual National Awards Program for Excellence in Concrete Pavement.
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The Isthmus of Panama became the principal transshipment point for Spanish treasure and supplies to and from Central and South America in colonial days.
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A form system often used in the construction of walls is the premanufactured, reusable handset.
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Hundreds of ready-made patterns are available in manufactured plastic form liners, and thousands more can be custom-made for projects with unique needs.
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One of the contractor's many responsibilities is the design and construction of shoring systems, which support the formwork system and construction loads.
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An octagonal concrete shaft for a new control tower at O'Hare International Airport, Chicago, was erected quickly and efficiently using a jump-forming system both for exterior and interior wall construction.
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Drawings and specification are the fundamental tools designers use to communicate their intentions to prospective builders.
The U.S. Federal Government has decided that it will switch to a metric-based system of weights and measures.
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OSHA has released its new fall-protection standards.
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When contractors plan bridge deck forms, they must carefully weigh the advantages and disadvantages of the available forming systems and materials.
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Bridge deck paving machines are set on top of and travel forward along screed rails during concrete placement.
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"A weak bridge is admittedly more dangerous than an ugly one, but to seek strength at the lowest cost with no regard for appearance is only one degree worse than it would be to attempt a beautiful design without thought of stability."
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The arrival of cold weather needn't halt concrete construction.
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To ensure that conditions are safe, companies should carefully evaluate their employees to find those capable and responsible enough to be an OSHA competent person.
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Students from the United States and Canada converged upon New Orleans, June 23-26, 1994, for the Seventh Annual American Society of Civil Engineers National Concrete Canoe Competition.
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Residential concrete fencing is versatile, durable, and maintenance free - the ideal addition to any home.
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Energy-efficient concrete tilt-up homes are making news in Pueblo, Colo., where Castle Construction Co. is using insulated concrete sandwich panels to build two different home designs.
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Current prescriptive design tables used for most residential concrete basement walls are based on the presumption that the soil used for backfill does not have a lateral pressure greater than 30 psff (pounds per square foot of wall surface per vertical foot of wall).
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Stamped and colored concrete mimics what it is not. The goal is to simulate natural stone, real brick, or glazed tile as closely as possible.
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Pumping usually is an efficient and safe way to move concrete. But like other jobs that require working with heavy equipment, pumping can be dangerous if not done correctly.
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The pumping operation starts with the discharge of the concrete, usually from a ready mix truck, into a hopper large enough to hold a small supply of fresh concrete.
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The three main causes of concrete pumping system blockages are: mix design deficiencies, pipeline and joint deficiencies, and operating error or careless use of the discharge hose.
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The key features of some of the newest models being offered include: Short boom sections that enhance maneuverability, long-reach booms and swing-valve boom pumps.
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Most hydraulic tools used at a jobsite require a self-contained hydraulic power unit that is powered by a diesel or gasoline engine or an electric motor.
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Using high-range water reducers, also known as superplasticizers, to increase slump may be necessary for difficult wall placements.
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One way to maximize the life expectancy and reduce the maintenance needs of an industrial concrete floor is to treat the surface with a metallic-aggregate dry-shake hardener.
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Mix four basic ingredients - water, cement, sand, and aggregate - and you have concrete.
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A material spreader is used to apply one of several types of material, including floor hardeners, coloring materials, light reflectants, and aggregates.
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Two new stormwater retention tanks recently built at BP Oil's refinery in Toledo, Ohio, feature the tallest reinforced-concrete radius walls in the country.
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The Mayfair Shopping Mall is an exclusive mall located in Coconut Grove, Fla., near Miami. The changing character and lifestyle of the neighborhood prompted the owners to do a little remodeling.
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Metal bar supports usually are made of plain or stainless steel wire and are one of the most common types used.
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As experienced concrete floor contractors know, no single mix design is suitable for all jobs.
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Using dry-shake color hardeners and a variety of stamping tools, contractor Mike DeReu, San Marcos, Calif., transforms conventional concrete flatwork into eyecatching walkways that embellish any outdoor setting.
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Leading flatwork finishing contractors tell "Concrete Construction" what it takes to be successful in the business.
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Saws for cutting concrete flatwork vary in size, blade type, operating speeds, cooling systems, and power source.
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Most contractors see F-numbers in the majority of specifications written today and most have read articles and publications on the subject.
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Hiring good finishers is key to a concrete contractor's success.
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According to OSHA, an employer is responsible for ensuring the availability, proper use, and maintenance of personal protective equipment. But employees also have a responsibility to preserve their health and safety by wearing the clothing provided and using it correctly.
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Concrete Construction asks leading concrete pavement contractors for tips on what it takes to be a successful paving contractor.
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On slope paving jobs, a slope paver, slope slipformer, or hydraulic roller screed can reduce labor requirements, increase production rates, and improve concrete uniformity.
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A key aspect to any quality concrete pavement is smoothness. To achieve the best possible quality, it is important to monitor pavement smoothness daily.
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Finishing, texturing, and curing concrete immediately after slipforming keeps work moving on fast-track paving projects.
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Portable generators power equipment and tools on jobsites where electricity is not yet available.
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In the case Granite Construction Co. vs. United States (1992), the U.S. Court of Appeals ruled that when a contractor substantially - but not strictly - complies with a contract's specifications, the owner may not require replacement of the work if replacement would amount to economic waste.
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One of the great engineering wonders of the world - the Detroit-Windsor Tunnel - was renovated for the first time in 1993 after 63 years of round-the-clock operation.
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Generally, epoxy-coated rebar have performed well in resisting corrosion in deicing-salt environments. But there have been isolated incidents, primarily in structures located in sea water environments, of unsatisfactory performance.
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In low- to mid-sized structures, it's often unnecessary and uneconomical to follow a design code that encompasses all structures.
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The overall safety and efficiency of many construction activities depends, to a large extent, on the quality and design of the tools being used.
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Four winners were named in the Concrete Reinforcing Steel Institute's 1994 Design Award competition.
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There are five commonly used procedures for designing industrial floor slabs.
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Concrete is the material of choice for many architects and structural designers because of the vast spectrum of alternatives it offers.
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Elements key to good whitetopping design include adequate pavement thickness, concrete strength, drainage, and jointing.
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According to a U.S. Department of Labor publication the problem of protruding steel rebar is one of the top physical hazards OSHA inspectors found on construction sites.
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In October 1994, J.J. Henderson Construction Co., Gurnee, Ill., successfully completed one of its biggest challenges - a large monolithic wall pour requiring placement of 712 cubic yards of concrete in seven hours.
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When city officials in Topeka, Kan., approved construction of a Melan system reinforced concrete bridge in 1896, local papers said it was "the greatest invention in bridge-building science since the parabolic truss."
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Although concrete pavement is not new to John F. Kennedy International Airport, LaGuardia Airport, or Newark International Airport, recent taxiway and apron paving projects have seen a dramatic increase in its use.
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Some design requirements for concrete construction, such as seismic post-tensioning, can result in congested areas within the formwork that are difficult to consolidate.
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There are several features common to concretes made with fine grades of GGBF (ground granulated blast-furnace) slag.
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In most cities, baseball fans only dream of a stadium where they can be closer to home plate than the pitcher.
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Water repellents offer the advantage of preventing water from penetrating concrete surfaces without significantly changing the appearance of the concrete.
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As an investigator and accident prevention specialist in the construction industry, an opportunity to tour Russia in March 1993 allowed me to examine that nation's construction methods and learn more about its culture.
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The Michigan Department of Transportation (MDOT) is the first agency in the U.S. to test European pavement technology on a major interstate highway.
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A terraced dining patio adjoining the Kula Lodge on the Hawaiian island of Maui required special seating arrangements to take advantage of the spectacular view of both sides of the island.
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Formwork is a major contributor to profitability - or the lack of it- on most concrete jobs.
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Built by Gibbs Construction Co., New Orleans, the 207-foot-high tower welcomes all travelers coming into New Orleans International Airport.
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Rarely will a laboratory mix be entirely suitable under the variable field conditions facing a concrete contractor.
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Many contractors use long-strip construction as an efficient concrete placement method for slabs on grade.
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With more than 100 operators nominated to win the Operator Safety Award for concrete pump operators, it's easy to see why Jerry Brooke's chances of having his name selected as the winner were pretty slim.
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Ten curved tilt-up sandwich panels were used to construct a 300,000-square-foot apparel distribution center in Troy, Ohio.
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OSHA provides free on-site consultation services to employers in all states who want help recognizing and correcting safety hazards at their workplaces.
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The New Orleans District of the U.S. Army Corps of Engineers is responsible for flood protection and water resource development in a 30,000-square-mile area covering most of southern Louisiana.
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On first thought, building a 2-mile section of elevated, twin bridge interstate highway doesn't seem like an especially challenging project
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I arrived at the job near the end of the day's slab placement to find the finishers picking clumps of cement out of the mix during finishing. They continued finishing, and the floor is now in place. I was upset with the foreman on the job for not rejectin
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When designing one-sided wall forms, what lateral pressures should I use?
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Before placing the concrete for the last pier of a drilled-pier foundation job, the foreman decided to add water to the ready mix truck. The inspector didn't like the looks of the watered-down concrete and took test cylinders that represented that one pie
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I understand the effects chlorides have on reinforcing steel in concrete. What effects, if any, do chlorides have on plain, nonreinforced concrete, which is typically used in sidewalks and driveways?
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We heard that the greenish blue discoloration often found on concrete containing slag can be removed with a 3% hydrogen peroxide solution. Our experience suggests that this treatment may lead to scaling of early-age concrete. We found dilute solutions of
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I am involved with a large urban concrete project where concrete delivery is sometimes delayed by traffic congestion. The specification requires concrete placement within 90 minutes of batching at the plant. What is the significance of this 90-minute spec
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Why do manufacturers limit the content of air in concrete in floors that are going to receive a dry-shake metallic floor hardener?
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We're on a job that requires the microsilica concrete to be less than 600 coulombs chloride permeability at 28 days for laboratory-cured specimens and at 80 days for field-cured core samples, as measured in accordance with AASHTO T 277-83. There's a pay r
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We always have a difficult time hiring good shotcrete nozzlemen. When interviewing nozzlemen, how can we screen those who can shoot well from those who can only talk about shooting?
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Is there information available, such as research, case studies, and field experiences, that documents the long-term performance of polyethylene sheets used as vapor barriers beneath concrete slabs on grade? Currently, what little evidence I have indicates
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What causes my bull floats to warp within a couple of months after purchasing? I buy magnesium floats with ribs to protect them from warping. I store the floats in the bed of my truck, leaning against the cab.
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Last summer, we built a slab-on-grade concrete parking lot. This winter, our finishing techniques are being blamed for damage caused by a plow during snow removal. The building supervisor is complaining about the joints that we hand-tooled. He's claiming
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How frequently should I replace my crew's hard hats?
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What is the difference between waterproofing and dampproofing?
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The project inspector is requiring us to wire-brush mill scale and rust off all our rebar. Although the rebar has been at the site for a couple of weeks, we don't think the rust is that heavy or will interfere with the bond between the concrete and steel.
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We've been asked to provide a floor with a tolerance of 0.02 inch in 10 feet. Has anyone built a floor to this tolerance? Is it possible?
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What are the thickness tolerances applicable to slabs on grade?
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What are gap-graded aggregates and how are they used in concrete construction?
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What is bushhammering and how is it used in concrete construction?
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How high can concrete be pumped vertically?
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We had some complaints on a recent job about ammonia smells coming from concrete placed in a confined area. What causes this smell?