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  • The Case for Early-Entry Saws

    There's an ongoing debate about the minimum sawcut joint depth needed to minimize random cracking in pavements. For many years, specifiers have required a minimum depth one-third or one-fourth the slab thickness, with the deeper cuts being used for longitudinal joints in highway pavements. Many...

     

  • Justice Center for All

    When the Las Vegas Justice Center is complete in February 2002, it will comprise 710,000 square feet of space. The main structural elements of the concrete-frame building include an 18-story high-rise tower, a 5-story low-rise building, and an independent elevator tower with footbridges connecting...

     

  • Pumps for Wet-Mix Shotcreting

    The number of construction projects using wet-mix instead of dry-mix shotcrete continues to grow, primarily because wet-mix shotcreting can achieve a higher production rate. Contractors using this concrete placing method have a number of pump options. But what's the best pump type to own or rent...

     

  • Going Hybrid

    How can designers improve the quality, efficiency, and safety of construction operations? In the United Kingdom, greater use of hybrid structures may be the answer. By combining a variety of appropriate structural elements in one building, architects and designers can offer their clients a wide...

     

  • Connecting the Dots

    Connect the dots, color between the lines, and share. These lessons we learned in kindergarten can be applied throughout our lives and even on the jobsite. Taylor Ball, San Diego, recently applied the first lesson by taking a simple connect-the-dots approach to the layout of footing excavations and...

     

  • Testing a Petrographer's Conclusions

    During the summer of 1999, a concrete contractor placed an exterior parking lot for a commercial building in the Midwest. The concrete was air entrained and received a broomed finish, followed by 3 days of moist curing with plastic-coated burlap. Because some of the concrete set at a different rate...

     

  • Removable Forms for Concrete Homes

    Imagine living in a house that is fireproof, can safely protect you and your family from tornadoes and hurricanes, and is earthquake resistant. Your costs for heating and air conditioning are greatly reduced (at a time when energy costs could double), you have no need to worry about termites and...

     

PROBLEM CLINIC

  • When to Wash Decorative Concrete

    We've just started doing decorative concrete work and want to know how soon to power-wash and seal a colored surface after concrete placement.

     

  • Pumping Without Consolidating

    A large number of 2- and 3-foot diameter, 18-foot-high concrete columns were placed on caissons without the required reinforcing steel that connects the caissons and columns. To repair this, the contractor had to drill holes in the caisson outside each co

     

  • Rolling Stones

    We supplied concrete for a large floor, which the concrete contractor placed using a laser-guided self-propelled screed and riding power trowels. He initially floated the surface with pans and then used combo blades for later floating and troweling. During the late troweling stages, the blades were...

     

  • Cracks at the Ends of Sawed Joints

    When we saw contraction joints for slabs placed when walls are already in place, we have to end the cut 2 to 4 inches from each wall, depending on the saw-blade diameter. The crack that forms at the end--as a continuation of the cut--is never straight. Is there any way to saw joints all the way to...