2018 Research:
TCA is a 10-plus year supporter of the RMC Foundation with an annual pledge of $1000 to the Foundation. Through 2018, TCA has contributed $16,000 to the RMC Foundation.
Beneficiated Fly Ash Research Project:
Because a reliable, consistent source of fly ash is so critical to the concrete’s industry ability to produce durable, high performance concrete TCA has been active in lobbying the Tennessee Valley Authority to switch from landfilling fly ash at several coal-fired power plants in Tennessee to investing in one of several beneficiation processes that could turn TVA’s disposal problem into a profit opportunity while preserving and extending a vital resource for the concrete industry in Tennessee and surrounding states. TCA filed a report with the presiding judge in a lawsuit involving the TVA Gallatin Power Plant where the judge ordered TVA to excavate nearly 12 million tons of fly ash from unlined storage pits and move it to lined storage facilities. TCA made a strong case that a much wiser course of action would be to beneficiate the fly ash during the relocation process to produce a commercially viable product for industry to use while eliminating a huge and ongoing environmental risk for TVA. While no final decision has been made, TVA is in serious talks with fly ash producers regarding the installation of beneficiation technology at TVA locations. A copy of the letter prepared by TCA and submitted to the judge is attached HERE.
To support this work to bring more beneficiated fly ash to the market in Tennessee, TCA worked with long-time research partner Dr. L.K. Crouch at Tennessee Technological University to do a study on the impact of using beneficiated fly ash in concrete mixtures utilizing common Tennessee materials. The research was performed by students at TTU in the summer of 2018. An abstract of the research project can be seen HERE. This research will be presented by TTU at the 2019 World of Coal Ash.
ACI 332 Mix Design Research:
The TCA Technical Committee came together to test both the fresh and hardened properties of mixes typically supplied for residential concrete driveways. Different mixes were run in the lab to simulate what happens to concrete when a producer’s mixes are subject to the addition of water (often significant amounts of water) at the jobsite. Tests were run to determine properties both before and after the addition of water, including the collection of calometric data above to show the impact of water addition on set times. While there were no surprises in the data, it was very useful to show not only the reduction in the strength that comes from water addition, but also the increase in set time. Data can be found HERE.
Commercial & Residential Enhanced Durability (CRED) Research:
This study was undertaken to support the work of the TCA Technical Committee with regard to ACI 332 and exterior concrete durability (see more detail in the Codes section). Because of the increasing prevalence of magnesium chloride in commercially available de-icing products, this research was designed to focus on potential impacts from the use of these products on common concrete mixtures being used in Tennessee. Phase One of the study was completed in 2018 and results can be seen HERE. As expected, impacts of the use of de-icers can be measured and the research demonstrated these impacts. More research work has been approved for 2019 to quantify the impacts of de-icers (especially magnesium chloride) on common commercial and residential mixes used in Tennessee. This information will be used to help TCA communicate the importance of using better mixes to insure long-term durability of exterior concrete as well as communicating to owners the dangers to even good quality concrete presented by the use of de-icing chemicals.
Portland Limestone Cement (PLC) Research:
PLC is not widely used in Tennessee as of 2018, with only one cement supplier marketing PLC in Tennessee (at only one terminal in Memphis, TN). However, it appears that PLC may increase in both availability and use going forward so TCA responded to a research request from students at TTU interested in comparing concrete mixtures utilizing PLC to those using conventional Type 1 cement. TCA helped in getting a sample of PLC to the TTU campus and students were able to begin their research. A plan of the research can be seen HERE.
2017 Research:
Research: Finishing & Handling
The TCA Campus provided space for a new research project with a proprietary product in 2017. The project involved both engineering properties of the concrete mix design and the finishing and handling characteristics of the mix. MTSU provided the testing services for the engineering portion of the study and two TCA contractor members worked on the project to provide feedback on finishing and handling of the mix. Five slabs totaling 40 cubic yards of concrete were placed (on the same day) for the project and all slabs included internal wireless sensors to transmit temperature and humidity information. Information is transmitted via Bluetooth to an I-phone app where it can be accessed, downloaded and shared with the participants in the project.
Pervious Cleaning Research
TCA also gathered data from several pervious concrete cleaning projects in 2017 & 2018 to add to our database of cleaning information from prior years. TCA is one of the pioneers to seek out and validate the best methods of maintain and cleaning pervious concrete pavements and we take a research-based approach to our cleaning projects. TCA gathers data on before and after infiltration (using ASTM C-1701 as our test method) along with recording the time required to clean pavements and the amount of sediment removed from these pavements. This info has been compiled into presentations and shared with various industry and allied groups to demonstrate in a factual way that pervious concrete can be easily maintained and that clogged pavements can be remediated successfully.
2016 Research:
Pervious Research
TCA planned and executed a large pervious concrete research project in collaboration with Middle Tennessee State University in the summer of 2016. Phase Two of this large project (about 800 cubic yards of pervious concrete were placed for this project) carried into 2017 and was focused on pervious concrete additives and/or mix designs that can provide enhanced resistance to chemical deicers. This part of the study is being done by faculty at MTSU with TCA serving in an advisory capacity. Results from Phase One of the study (focused primarily on mix design and engineering properties) have been reported at ACI and a final report will be presented by Dr. Heather Brown (MTSU) at the spring ACI Convention in 2018. A report on the engineering properties of the 18 control mix design tests is attached as a sample.
