Eco Concrete Questions

ACI Eco Concrete Competition Questions

**NOTE: The objectives listed on our web page have been updated to correspond with the rules. Please refer to the RULES for the most accurate and up to date information.

Q: Do we have to submit the mtds for every material (cementitious and aggregates) we used? Or just for those one that are ASCM? I mean, for those that doesn't appears in any ASTM standard.

A: The physical and/or chemical specifications of the mixture constituents should be clearly presented in the MTDs.

Q: In the ecoconcrete rules file, in the part of the written report, where talks about the abstract, the subsection 4 says that we have to make a brief description of the environmental, compressive and durability results. What do we have to write about this? Do we have to write the results of the compressive strength test and the electric bulk resistivity? 

A: Considering the limitation in number of words, the obtained mechanical, durability, and environmental results can be briefly stated along with a very abstract explanation.

Q: What specimens does each team need to bring to the competition?

A: According to section 1.1 of the rules (last paragraph), teams shall submit four cylinders, two for each case, on Sunday morning.

Q: How do we get our specimens to SSD condition prior to competition?

A: To ensure the maintenance of SSD condition for the specimens, teams are encouraged to submerge them in the water before the competition. When traveling, it would be a choice to wrap and seal the specimens with air bubble wrap roll.  It is also recommended to read the FAQ section of the competition page for more information.

Q: According to point 2.7, section b, a negative improvement can be scored, but we have the doubt if the justification presented in the report will be taken into account? As a typical behavior of the pozzolans is a low resistance at early ages but according to the slope of its development to compressive strength it is possible to predict the behavior that often exceeds the conventional concrete mixtureThe compressive strength sheet shall be filled before the competition day?

A: We will test the compressive strength of the BCS and ACS specimens in Quebec City. As stated in section 2.7 of the rules, “SCMs typically require 28 to 56 days to develop their effect on compressive strength”. Therefore, we recommend to cast the specimens and to cure them early enough in order to achieve the positive effect of incorporating pozzolans in the ACS mixture.

Q: Teams must fill MTDS for all agregates? (Coarse and fine agregates)

A: Yes.

Q: The software for Eco's Mix Design does not allow us to change the type of coarse and fine aggregate.

A: The primary coarse and fine aggregates as well their transportation distance to the plant will be fixed in both scenarios to keep the consistency of primary materials suppliers. Nevertheless, teams can add new rows by clicking on the “green +” sign next to “Aggregates” to define the alternative aggregates, such as recycled aggregates.  You can find an example of defining recycled aggregates in attached screenshot. In this example, it is assumed that 100% of the primary aggregates is replaced by the recycled materials and therefore, the mass of primary aggregates in the ACS sheet is zero. However, this replacement can be partial.  It should be noted that the transportation distance from the landfill to the recycling plant and from the recycling plant to the concrete plant (in this competition, it is assumed as the University location) shall be included in the appropriate places. The quantity of electricity and/or heat required to process the recycled materials (e.g. crushing, sieving, etc.) shall also be considered in the calculation for each recycled material.

Q: Can we assume that our BCS and ACS should have the same mass?

A: The BCS and ACS mix designs usually have different unit weights. As for one cubic meter mixture, the masses would be different. Further discussion of the design of concrete mixtures, incorporating various alternative materials, with team advisor or mentor is recommended.

Q: Are we supposed to use the quantities that are already in place on the Calculation Tool spreadsheet as our Base-case Scenario or are we suppose to develop our own unique Base-case Scenario? 

A: The BCS mix design and curing condition shall comply with the rules specified in section 2.3-2.5. The default values of the mixture constituents can be adjusted according to these rules.

Q: Should the total volume of our mixture be taken into consideration with regards to reduction? 

A: The replacement of various alternative materials, which have different unit weights than primary materials, can eventually alter the unit weight of ACS compared to BCS. Teams shall mention the mass of constituents for one cubic meter of concrete mixture in the spreadsheet, the report, and the poster. In fact, one cubic meter of ACS shall be compared to one cubic meter of BCS.

Q: Can we use the Vancuver style for textual citations? 

A: Following citation styles can be used in the report and poster. One citation style shall be consistently followed for all the references. (MLA, APA, Chicago, Harvard, Vancouver)

Q: Are glass fibers, wire fibers, and others fibers allowed?

A: Fibers are allowed in the ACS but prohibited in the BCS.

Q: From System Boundaries under LCA section, do we need to make a similar figure (1) for each material?

A: One system boundary for each case is enough to include all the cradle-to-gate processes.  The dash line box in Figure 1 delimits the system boundary explained in section 2.5. Therefore, all the processes located inside the box are included in the system boundary of this system analysis (For more information, you may refer to ISO 14044).

Q: May we use DRY ICE in our mixture to incorporate carbon?

A: The chemical admixtures complying with ASTM C494 and C1017 can be used in the mixtures. Other chemical admixtures are prohibited.

Q: Should we prepare the concrete specimens to the journey in the way providing the fully maintenance of a water content in concrete at a level of 100%?  

A: To ensure the maintenance of SSD condition for the specimens, teams are encouraged to submerge them in the water before the competition. When traveling, it would be a choice to wrap and seal the specimens with air bubble wrap roll.

Q: Should the graduate student who’s assisting us be added as a “team member?”

A: Each team can ask the help of one graduate student (Ph.D. or master student) to participate in the mix design and the simplified life-cycle assessment (LCA), and the student shall be mentioned in the report. It means that jury members can recognize the name of the graduate student in the report. They should not be added as a member of the team.

Q: What kind of filler can be used?

A: As stated in the competition rules, mineral fillers, complying with ASTM C1797, are allowed.

Q: Is there a possibility of using the CPV (High initial strength - NBR) cement that is equivalent to the CPIII of ASTM C150? If we can get a CPIII intermediate blaine cement (450 m² / kg) can we use it in the competition?

A: Teams are strongly encouraged to carefully read both ASTM C150 and C1157 to understand if their cement specifications fits the type I or II and type GU, respectively. 

Q: Can the samples be of different ages?

A: Teams are encouraged to cast ACS and BSC at the same day. Also, teams are suggested to cast specimens 28-56 days before the competition day. It should be noted that the curing shall be performed for more than 14 days.

Q: We would kindly like to know the composition of cement classified as normal type I. Are all the materials corresponding to this cement clinker + gypsum?
Also, Cement Type II - Moderate Resistance to Sulphate and Type V - High resistance to Sulfate are present in the ASTM nomenclature. In the NBR (Brazil) standard, we only have the type of cement with resistance to sulphate. What is the difference between the types of cement with sulfate resistance of the American standard? So that we can evaluate the choice of our material.

A: The C150 standard addresses  the chemical and physical properties of these portland cements. Teams are encouraged to read those specifications to understand if their portland cement are complied with the limitations of the standard. In fact, if there is a portland cement in Brazil with the similar specifications of type II, this team would be free to use it for the eco concrete competition. It should be kept in mind that blended cements are prohibited to use in the BCS.

Q: Is it possible to get a Calculation Tool file in the US system of units (lbs, ft, etc) for  the Eco Concrete student competition?

A: It was decided we would standardize the use of SI units, as accommodating dual units has imposed quite a challenge (especially for prices per ton, and for cost relative to concrete volume).  In addition, the US metric is not defined for the environmental impact assessment, such as ecotoxicity and carcinogenic. To keep it constant, we went for the SI metrics.

Q: Can 1 team from the same school participate in both student competitions in Spring 2019, Quebec, Canada?

A: Yes! EcoConcrete requires a minimum of 1 team member be present at the competition and Mortar Workability requires 2 team members be present at the competition.  Thus, as  long as 3 team members can attend the competition in Canada, you may participate in both.  The entire team members who make up each team for Eco & Mortar may be alike.

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