EPD Competition Questions
Q. Reinforcement in the device: Should the device include reinforcement (be made of reinforced concrete), or is the only permissible reinforcement the fibers described in the ASTM standards outlined in the competition rules?
A. See 3.3, with attention to 3.3.4. Fibers conforming to ASTM C1116 Section 4 are the only permissible reinforcement.
Q. Metallic aggregates: In section 3.1.1.3, when it states that "metallic aggregates are not permitted," does this refer specifically to metallic fibers or to steel bars?
A. This refers to metallic aggregates (e.g., steel shot). Steel bars are not permitted. Metallic fibers are permitted per 3.3.
Q. Composition of test cubes: Should the cubes only contain a concrete mixture, without any type of fibers, special aggregates, or other additional elements?
A. See 2.3.2. Cubes shall be cast from the UHPC matrix only, comprising the same ingredients and proportions as the UHPC mixture but without fibers.
Q. Aggregate size: The permitted aggregate size is not entirely clear to us. Could you please clarify this point?
A. There are no restrictions on aggregate size.
Q. Is the use of carbon fibers allowed in the concrete mixture, in accordance with the competition guidelines?
A. Fibers of any kind are allowed as long as they conform to Section 3.3 of the Rules and Section 4 of ASTM C1116.
Q. The fibers I’m planning on using have a specified length of 2 in. (approximately 51 mm); would it be acceptable to use them?
A. Fibers with a nominal size of 2 in. (50.8 mm) will be allowed.
Q. We had gone through and saw that there was no specified psi to meet in the requirements. Would you be able to clarify the minimum psi is or is the expected 22000 psi?
A. ACI Committee 239 recently released ACI PRC 239.1-24, which states that "the minimum compressive strength of UHPC is commonly required to be 17.5 ksi (120 MPa) and also defines other typical characteristics of UHPC. We encourage teams to adhere to these guidelines, but there will be no disqualifications or points lost for failing to achieve any minimum compressive strength.
Q. I wanted to ask if it would be possible for us to proceed with a concrete pour this week without performing the full 28-day cylinder tests?
A. Teams are not required to perform 28-day cylinder breaks. Per 2.1, teams must submit three 50-mm cubes of UHPC matrix only. Per 4.1.4, teams must include a predicted compressive strength in their report. The prediction should be based on laboratory testing, but this is not a requirement.
Q. What's the diameter of the weight?
A. The weight is approximately 75 mm (3 in) in diameter
Q. Is it acceptable to use SikaGrout®-215, which is a pre-packaged cementitious grout? The Product Data Sheet does not specify that SikaGrout®-215 is a proprietary UHPC product.
A. This specific product is not UHPC. There is nothing in the Rules to disallow its use but, per 3.1, proprietary products shall be mixed in proportions specified by the manufacturer. That means additives or components (fibers, admixtures, etc) not specifically referenced in the product data sheet cannot be added.
Q. Is it acceptable to use Sika ViscoCrete®-3115 N, which is a superplasticizer? The Product Data Sheet does not state that it complies with ASTM standards, whereas other Sika ViscoCrete® products such as ViscoCrete®-1000, ViscoCrete®-1100, and ViscoCrete®-2100 are specified to meet ASTM C494.
A. Per 3.1.1.2, admixtures must meet the specifications of ASTM C494. If the team cannot provide a technical data sheet showing a material meets a required specification, 4.1.5.2.1 allows the team to instead submit a letter from the manufacturer stating the product meets the requirements of that specification.
Q. After doing some research we found that all cement in the Egyptian market is produced in compliance with the Egyptian and European standard specifications with no locally produced cement meeting ASTM standard specifications, our question is can we use our locally produced cement meeting Egypt and European and is there a guidance that tells whether which European standard specification is equivalent to what ASTM standard specification?
A. In parts of the world where available materials are not evaluated against ASTM specifications, teams should provide mill certificates or other reports that detail the composition or relevant properties of the material. The advisor should provide a letter from the manufacturer, supplier, or faculty advisor attesting that the materials are functionally equivalent to those specified by the ASTM standards referenced in the Rules.
Q. We are thinking of adding foam in our EPD. Would using foam material be a cause of disqualification?
A. Foam is not an allowable material and its inclusion in an EPD will result in disqualification.
Q: In section 2.2.2 in the EPD Competition Rules, it states "Shall include an opening that allows clear passage of a rectangular template measuring 275 mm (10.83 in) in width and 175 mm (8.27 in) in height". Though when you convert the 175 mm to inches, it's 6.89in, not 8.27in as stated in the rules. - Can we get clarification on which of these dimensions is correct?
A. It should read 175 mm (6.89 in)
Q. There was no information on where the weight would be dropped on the EPD. - Can we assume it will be dropped on the center of the EPD?
A. The load will be dropped on the center of the top face of the EPD
Student Competition Questions
Please contact:
Jaeden Jackson
American Concrete Institute
38800 Country Club Drive
Farmington Hills, MI 48331
Fax: +1.248.848.3701
Email: students@concrete.org