Shotcrete is a placement method for concrete so most admixture or supplemental cementitious materials that can be used in cast concrete will work with shotcrete placement. In fact, shotcrete contractors have been some of the most innovative adopters of new concrete technologies. Silica fume (microsilica) is a ultrafine particle 100 times smaller than cement that enjoys early and wide use in shotcrete due to its ability to make concrete stickier and more cohesive. This facilitates overhead placements and can provide thicker layers. Shotcrete has also used other ultrafine and nanoparticles, like colloidal silica, clay-based particles and the carbon nanotubes you mentioned.
The ultrafine and nanoparticles can provide many benefits to fresh concrete, as well as hardened properties. This may include:
• Improve the pumpability of wet-mix concrete;
• Reduce rebound and dust due to increased “stickiness”;
• Ease the finishing process;
• Reduced permeability by filling pores between cement in the paste;
• Enhanced corrosion resistance for embedded reinforcement;
• Enhanced resistance to chemical attack.
Yes, shotcrete is a placement method for concrete, so any coating appropriate for concrete would be applicable specify new concrete should be a certain age before applying their coating. Generally, the concrete surface should be clean and dry before coating. The surface texture provided on the shotcrete can affect the coating application. A hard, smooth steel trowel finish will tend to be quite slick, and the coating may not bond as well as a floated or sponge finish. A light abrasive blast may be considered to roughen the surface and give more bond. If using a gun or rodded finish for the shotcrete, the coating will generally require quite a bit more material to be able to fill the depressions in the surface.
Code of Conduct
As an ASA Qualified Shotcrete Contractor we agree to ongoing compliance with the requirements and standards set forth in the ASA Shotcrete Contractor Qualification Program Description. We will not knowingly or purposefully violate any project specifications or requirements. We agree to maintain the required insurance coverage, staff our projects with trained and certified personnel, and strive to produce a high-quality product in a safe and professional manner.
Agreement
- a) The ASA decisions concerning qualification, including but not limited to the decision of the CQC shall be final and binding;
- b) The applicant will not institute legal action of any kind to challenge those decisions;
- c) Neither the ASA nor its members, officers, employees or representatives (including but not limited to the members of the CQC) shall be subject to any claim for legal or equitable relief (including but not limited to money judgements and injunctive relief) arising out of those decisions; and, in any event,
- d)Neither the ASA nor its members, officers, employees or representatives (including but not limited to the members of the CQC) shall be liable for consequential or incidental damages of any kind as a result of the ASA Qualification program. The applicant further agrees that if it commences legal action in violation of this agreement, it shall be responsible for paying all costs and expenses, including attorney fees incurred by ASA and/or its members, officers, employees or representatives in the course of defending that legal action.
Indemnification:
In the event that any party asserts a claim for personal injury, property damage, economic loss of other damages against ASA and/or its members, officers, employees or representatives arising out of or relating to the acts or omissions of an ASA Qualified Shotcrete Contractor, the ASA Qualified Shotcrete Contractor shall, upon request, defend and indemnify ASA and/or its members, officers, employees or representatives and hold them harmless from all damages, judgement, costs, losses and expenses, including attorney fees, resulting from said claim.
Authorization:
I have read and agreed to the above disclosures. I authorize the verification of the information provided on this form and declare that it is accurate to the best of my knowledge. By checking this box, I authorize my consent.
Contractor Qualification Program
When you have completed your application and compiled all required documents, you are ready to submit your application.
Checklist of Required Materials to Upload:
- ASA Seminar Certificate of Completion
- ASA CQ Program Status Report (Exam score)
- Current Contractor’s License
- Current Insurance Certificate
- Current Letter of Bonding Capacity
- Completed ASA CQ Application pdf
- Completed ASA CQ Application xlsx – 3 tabs: Equipment, Field Teams, & Projects
- Application Fee – Payable online after submission
Copyright © American Shotcrete Association
ASA administers the Shotcrete Contractor Qualification as a review service for shotcrete contractors, providing them with objective, experienced review of their projects, equipment, and company structure for project owners who might have less experience evaluating shotcrete work. This review is conducted by the Review Task Group within the Contractor Qualification Committee, whose members have extensive experience in successful shotcrete work. This qualification program provides a distinct service to the industry by assuring specifiers that shotcrete contractors reviewed here have a proven work record for completion of successful projects of similar work and scope. This qualification program is based on the ASA Board Position Paper, “Qualifications of the Shotcrete Construction Team.”
Structural Levels of Qualification:
There are two structural levels of qualification, Level I and Level II in the process(es), i.e. wet-mix or dry-mix, to the work performed by applicant.
- Qualified Shotcrete Contractor – Structural Level I (QSC – SI) Shotcrete Contractor (Level I) – Representative projects which have thin, lightly-reinforced shotcrete sections that can be easily accessed and placed would be considered “Level I”.
- Qualified Shotcrete Contractor – Structural Level II (QSC – SII) Shotcrete Contractor (Level II) – Representative projects which have thick, heavily-reinforced sections or sections with difficult access would be considered “Level II”.
Program Requirements:
- Identify a Qualifying Individual (QI) to attend the required CQ Seminar and successfully complete the required written exam. Please contact ASA for the next available seminar: [email protected] | 248/983.1702. (The seminar will also provide helpful insights for completion of the CQ application.)
- Documentation of company equipment and shotcrete staff, including list of certified shotcreters (previously known as nozzlemen)
- Documentation of FIFTEEN (15) projects successfully completed in the last 3 – 5 years (per level pursued) representative of the level of qualification pursued in the application.
Click here to review the full policy for help in completing your application
If you have any questions, please contact ASA at 248.983.1702 or [email protected]
Copyright © American Shotcrete Association
We have all seen those small letters and numbers that mark practically everything we use in construction. To most, these are meaningless markings that are meant for someone else. However, with shotcrete, nothing could be farther from the truth.
The COVID-19 Pandemic affected our lives in ways none of us have ever experienced in our lifetimes. I’ve been in construction for 45 years and I have never seen our economy shut down, businesses closed, or people required to stay at home. In 2001, the attacks of September 11th temporarily shut down air travel and the stock market, but the American economy remained intact and air travel resumed within a couple of weeks. However, COVID-19, has affected our lives in ways that we could never have imagined. Schools and universities were closed; professional, collegiate and high school sports seasons were suspended and canceled; and restaurants and businesses were closed. We were told to stay home and work remotely, if possible, and businesses across the country followed those directives.
This is a revised version of the original article printed in the Summer 2016 of Shotcrete magazine before the OSHA rule was put in place. This revision has added site measured values for air monitoring of crew members on shotcrete projects, as well as ASA’s response to OSHA’s request for information in August 2019. Also, included is a short section on applicable respirators. With this revision our intent is to put the current information you need about the OSHA rule and its impact on shotcrete operations in one place for ready reference.
