More stories about Ready-Mixed Concrete

  • Do Fibers Reduce Permeability?

    A customer has asked us to include fibers in the mix design for a water retention tank. The idea is that the fibers will reduce the permeability of the concrete. Is that true?

  • Nitpicking Slump-Test Results

    A testing firm employee says concrete should be rejected if the slump exceeds the maximum allowable value by as little as 1/4 inch. Is there any published information to help us argue our case?

  • Who Pays for Comparative Testing?

    We're supplying concrete for a parking deck, to be placed by boom pump. The required air content is 4.5% to 7.5%, and, to account for air lost during pumping, specifications require the test lab to perform air-content tests on concrete sampled from the pump discharge hose. We prefer testing for air...

  • How Often to Check Mixing Drums

    We have our plants inspected and certified in accordance with the checklist in Section 3 of the National Ready Mixed Concrete Association's Quality Control Manual. This certification includes truck mixer inspection to ensure that there's no appreciable accumulation of hardened concrete in the drum...

  • Handling Low-Strength Test Results

    Are there any simple guidelines for use when we get low-strength test results? The low tests seem to make owners especially nervous, and we'd like to have an authoritative document that lays out a course of action following the report of a low test.

  • Does Cement Brand Affect Air Content?

    When we change from one cement brand to another, we often need to adjust the dosage of our air-entraining admixture. Sometimes a new shipment of cement from the same source also requires dosage changes. Is this normal, or are we doing something wrong?

  • Acidic Mix Water

    Our water source for use in ready-mixed concrete is acidic, with a pH ranging from 5 to 6. What are the effects of this low pH, and what can be done to reduce acidity?

  • A Possible Use for Reclaimer Sludge

    Can reclaimer sludge be used to reduce soil acidity?

  • Aggregate, concrete construction get new codes

    What are the new North American Industrial Classification System (NAICS) codes for aggregates and concrete construction businesses?

  • Controlling Material Costs