Universal and Excavatable Controlled Low Strength Material Using High Loss on Ignition Fly Ash and Limestone Screenings†

Authors

James T. Locum, Department of Civil and Environmental Engineering, Tennessee Tech University, 1020 Stadium Drive, Cookeville, TN 38505, USA
L.K. Crouch, Department of Civil and Environmental Engineering, Tennessee Tech University, 1020 Stadium Drive, Cookeville, TN 38505, USA
Daniel Badoe, Department of Civil and Environmental Engineering, Tennessee Tech University, 1020 Stadium Drive, Cookeville, TN 38505, USA

Document Type

Article

Abstract

Limestone screenings and high loss on ignition (LOI) fly ash are by-products that are stockpiling because of their unintentional production and the negative effects when utilized in portland cement concretes. The research objective was to investigate whether these by-products could produce controlled low strength materials (CLSMs) meeting the three types of Tennessee Department of Transportation (TDOT) 204.06 flowable fill specifications. TDOT defines these CLSMs as the following: general use, excavatable, and early strength. Each type is required to have an inverted slump flow of not less than 15 inches (38.1 cm) while meeting ASTM International D6024 at 24 hours. Because of trench unavailability, a 10-psi minimum compressive strength requirement was substituted for the ASTM D6024 ball drop. Early strength flowable fills must meet ASTM D6024 at 6 hours and provide a 30-psi minimum compressive strength at 24 hours. Excavatable flowable fills (EFFs) must also provide a 30-psi minimum at 28 days and a 140-psi maximum at 98 days. A universal flowable fill was produced without portland cement (PC), but by using an 11.1% LOI fly ash, class C fly ash, and limestone screenings. The EFF was produced using 92% high LOI fly ash and 7% PC by weight of the cementing materials. The results indicated that high LOI fly ash and limestone screenings can be combined to produce an excavatable CLSM satisfying TDOT CLSM requirements, and an universal CLSM can be produced that satisfies the requirements for general use, excavatable, and early strength TDOT CLSMs.

First Page

8

Last Page

14

DOI

https://doi.org/10.4177/CCGP-D-17-00007.1

Volume

10

Publication Date

1-1-2018

Recommended Citation

Locum, James T., L.K. Crouch, and Daniel Badoe. 2018. “Universal and Excavatable Controlled Low Strength Material Using High Loss on Ignition Fly Ash and Limestone Screenings.” Coal Combustion and Gasification Products 10 (1): 8–14. https://doi.org/10.4177/CCGP-D-17-00007.1.