Page 72

2013SumShotcreteEMag

Shotcrete FAQs As a service to our readers, each issue of Shotcrete will include selected questions and provide answers by the American Shotcrete Association (ASA). Questions can be submitted to info@shotcrete.org. Selected FAQs can also be found on the ASA website, http://shotcrete.org/pages/products-services/technical-questions.htm. Question: I need to specify a shotcrete cover to some structural cannot afford to have the hopper out of service for an extended steel in a coal dump hopper. The idea is to provide abrasion period. Is there a “high-early-” strength option for shotcrete and impact protection to the steel beams. However, the client as there is for cast-in-place concrete? Answer: There are prepackaged materials commercially available for impact and abrasion resistance. Please contact mate- rial suppliers from “ASA’s Buyers Guide” for product information: www.shotcrete. org/pages/products-services/Buyers- Guide/index.asp. Question: Is it critical for the early and intermediate compressive strength at 3 and 7 days, respectively, to be met for shotcrete applications for a rock fall face if the 28-day compressive strength is met? Answer: Compressive strength at 1, 3, and 7 days can be important to all for subsequent operations. In general, 7-day strengths are a good indicator of the ulti- mate 28-day strength. The need for early strength is an engineering and construc- tion sequence issue, not a normal or typical shotcrete requirement. Question: Can you send me a document Contractor Qualifications Nationally with ASA specifications for gunite cov- erage of reinforcing bar for swimming ACI Shotcrete Nozzleman Certification pools, please? Locally through California-based ACI Chapters Answer: ASA does not have such a docu- ment. The concrete cover for embedded reinforcing steel is subject to the local Building Codes and may be increased by the structural plans and specifica- tions produced by an Engineer or Archi- tect for a specific project. ACI 350-06, “Code Requirements for Environmental Engineering Concrete Structures and Commentary,” covers concrete struc- tures intended for water containment and would be applicable to pools. The ExaminEr following is a link to ACI’s bookstore: www.concrete.org/BookstoreNet/ ProductDetail.aspx?itemid=35006. Shotcrete Concrete Contractors Association www.shotcrete.us Question: I would appreciate if you could comment on a city of Los Angeles shot- crete code that requires that shotcrete lifts 70 Shotcrete • Summer 2013


2013SumShotcreteEMag
To see the actual publication please follow the link above