National Minerals Corporation – Fly Ash

Project Profiles

Project: US Bank Stadium

Owner: State of Minnesota

General Contractor: Mortenson

Precast Concrete: Wells Concrete

Fly Ash: Boswell Unit 3

Year: 2014 – 2016

Wells Concrete, the precast concrete supplier for US Bank Stadium chose to use class C fly ash from Boswell Energy Center to produce high-performance concrete (10,000 psi) for every one of the precast concrete elements used in this project. The elements include; stadia (bleacher seating), columns, beams and vomitory walls. Wells Concrete used 25% replacement of fly ash in all of its mixes for both performance and economic benefit to the project.

The fly ash produced by Boswell Energy Center and supplied by National Minerals Corporation helped enable this project achieve its LEED rating by locally sourcing a recyclable product. The fly ash used in this project not only improved the economics and performance of the concrete, it also replaced over 6,000 tons of Portland cement.


Project: I-35E M Pass Concrete Paving

Owner: Minnesota DOT

Location: St. Paul, MN

General Contractor: Ames Construction

Concrete Paving: PCi Roads

Fly Ash Source: Boswell Unit 3

Year: Summer 2015

MnDOT added new MnPass Express lanes on both directions of I-35E in St. Paul. This will be the first MnPASS investment in the East Metro area and an essential link for people commuting between downtown St. Paul and the suburbs to the north.

PCi Roads selected to use Boswell 3 fly ash at a cement replacement rate of 30% in the concrete mix for this project. 30% Boswell fly ash in the concrete allowed PCi to produce a consistent, air-entrained, low water- cementitious ratio concrete necessary for long term durability for this important roadway.

Over 4,000 tons of Boswell fly ash was beneficially re-used in constructing this new roadway.


Pozzostone – hydrated fly ash aggregate

Learn more about Pozzostone

Project: CVS Pharmacy Parking Lot

Location: West Des Moines Iowa

Year: 2015

General Contractor: Darland Construction Co.

Engineer: Bishop Engineering

Site Contractor: Grimes Asphalt

Total Tons: 1440

Project Description: Grimes Asphalt elected to use Pozzo-Stone as a sub-base material under asphalt. Because of the unique pozzolanic strengthening properties of pozzo-stone (hydrated fly ash aggregate), Grimes Asphalt was able to cut an inch of base asphalt out of this project.

Grimes Asphalt used 1,440 tons of pozzo stone as subbase in this pharmacy parking lot. Pozzo-stone down at a depth of 8 inches and topped with 5 inches of asphalt.