Under a master contract, The U.S. Army Corp’s (USACE) Louisville District issued a Task Order to Stantec to develop project specific concrete mix designs. Under a subconsultant agreement with Stantec, this entailed CTLGroup engineers traveling to various material suppliers in Kentucky and West Virginia and sampling the materials (cement, fly ash, slag cement and silica fume) for shipment to CTLGroup laboratories for trial batching of four (4) mix designs and constituent testing. Upon selection of the appropriate mixes, Semi-Adiabatic Temperature Rise testing was performed at a ready-mix facility near the dam site. The results of all mixing and testing were used to support a Level II Thermal Analysis and Thermal Control Plan for the mixes.
All aggregates were evaluated in accordance with ASTM C33, including the optional ASTM C1260 testing procedure. Further, various combinations of cementitious materials representing the utilized combinations in the developed concrete mixtures were tested for alkali-silica reactivity in accordance with ASTM C1567, as modified by the USACE.
Concrete trial batching and optimization was performed in the CTLGroup laboratory facility following the provisions of ASTM C192. Small initial trial batches were conducted to determine the appropriate chemical admixture dosages to achieve the target fresh properties. Additionally, compressive strength specimens were cast and tested.
Semi-adiabatic temperature testing utilizing three (3) super insulated 4-foot concrete cubes was performed at the ready-mix plant in KY under the supervision of CTLGroup. Temperature vs. time curves were created over a 30-day period. This data was utilized in the thermal control plan development.
Thermal analysis and multiple thermal control plans (TCP) were developed for mass concrete placements of the tower, tunnel and spillway. Each TCP utilized a different temperature differential limit to determine the appropriate limit that would minimize/prevent thermal cracking.
The dam improvements are pending additional federal funding as of 2024.
