Pervious Cylinder Competition Questions
Q: Can you send us all the pieces and sizes of the permeameter (dimensions) that you will use on the competition?
A: McMaster-Carr www.mcmaster.com
3 in. gate valve - 3999K22
12 in. long 4 in. ID acrylic: 8486K577
Quick-release worm clamp: 5588K12
Tire inner tube: 4991T33
Home Depot: www.homedepot.com
4 in. flex coupling
3 in. to 4 in. flex coupling
3 in. street elbow
American Cube Mold: www.americancubemold.com
Rubber bands - These are 1/2 in. in thickness and orange - I believe they are synthetic rubber and have a higher durometer than typical rubber bands
3 in. ACM1K-3
5 in. ACM1K-5
Q: What's the granulometric composition that the permeable concrete must have for the competition?
A: I believe you are asking about the required gradation of the aggregate for pervious concrete. Aggregates shall meet the rules, notably item 2.b., but there are no requirements for the gradation of the material; however, it must be measured and reported. ACI 522 offers guidance on aggregates for previous concrete mixtures.
Q: Can you send us the paper about the design prices?
A: While previous competitions included cost as a portion of the competition, that section has been removed. Please ensure you are using the correct version of the rules, which are located at www.concrete.org/students/studentcompetitions/perviousconcretecylindercompetition.aspx.
Q: Is the cylinder cut the day of the competition or do we have to cut before the competition? Also, do you have more information about the permeability test?
A: No, the cylinders should be fully prepared and in a dry condition at check-in the morning of the competition. We will not have equipment available for concrete sawing or cutting at the competition. The permeability test is a falling head infiltration test as described in the rules item 5.c.iii. The chamber is 4 in. ID and flow measured from 9 in. above the specimen until the water level reaches 1 in. above.
Q: I have a question regarding the acceptable mixture materials within the mixture design. The team was considering to use nanoparticles in the mixture. Is this acceptable within the rules? And if so, are there any restrictions within the material because nanoparticles vary in composition?
A: All mix ingredients would need to meet the requirements of section 2 of the rules. The applicable section depends on the use and properties of the material. An inert nanomaterial would need to meet the requirements of an aggregate and be included in the gradation. Pozzolanic nanomaterials such as colloidal silica would need to meet the requirements for cementitious and supplementary cementitious materials.
Q: Our team is considering to use a product called “colloidal nano-silica” as per the attached data sheet. The product has the same chemical composition as liquid silica fume, except that the size of silica particles is smaller. Would using this product be acceptable in the competition?
A: According to the rules, section 2.c., colloidal silica would be acceptable if it meets ASTM C1240.
Q: Are we allowed to use latex for the pervious concrete cylinder competition?
A: Materials used for the pervious concrete mixture must meet the requirements of section 2 of the rules. Section 2.d. lists the acceptable chemical admixtures, so any used would have to meet the requirements of that section.