Green Concrete

A Green Cement for Ready Mix Producers

The GREEN CEMENT used by GREEN CONCRETE USA can be used by ready mix producers. A fly ash silo is needed to receive and handle the fly ash. Admixture equipment would be needed to add the admixtures used to convert the fly ash into a GREEN CEMENT. Many of the ready mix plants already have fly ash silos. And most all of them have admixture equipment. The admixtures used by GREEN CONCRETE USA can be in either liquid or granular form. The GREEN CEMENT replaces the Portland cement. It is added into the mix along with aggregates and water to produce a GREEN CONCRETE. One big advantage for using a GREEN CEMENT would be that a ready mix producer could now advertize that they sells a GREEN CONCRETE. A second big advantage is that GREEN CEMENT costs less than regular Portland cement.

A Precasters Cement

This Green Cement is particularly well suited for use by wet precast concrete manufactures. The chemical composition can be adjusted slightly which can cause the user to change the properties of the cement. Strengths can be adjusted along with set times. Rapid set times are possible, even in cold weather. Quick turnaround times are possible, meaning more pours a day are possible. One big advantage for using a GREEN CEMENT would be that a concrete products producer could now advertize that they sells a GREENER CONCRETE PRODUCT. The second advantage again would be a cost savings.

Very Green Concrete

A typical cubic yard of concrete may consist of using 500 pounds of cement along with 3500 pounds of aggregates to make that one cubic yard. Using a GREEN CEMENT in that mix would produce a concrete that was about 12.5% GREEN. By using recycled aggregates, the GREEN content of the concrete can be greatly increased. GREEN CONCRETE USA used a fly ash and a bottom ash that came from two power plants near St. Louis, Missouri. The fly ash was converted to a GREEN CEMENT. Bottom ash was used for the aggregates for both the course and fine materials. This resulted in a concrete product that was 99% GREEN because of the 99% total recycled content. GREEN CONCRETE USA also made and tested a concrete using recycled old crushed concrete for the course aggregate. The testing was done in Green Belt, Maryland for a local ready mix producer. He furnished the recycled concrete and used his natural sand for the fine aggregate. Using GREEN CEMENT, the resulting concrete was 73% GREEN. The 28 day compressive strengths exceeded 4500 psi.

Roller Compacted Concrete (RCC)

This cement can also be used for RCC operations. Many RCC uses require large volumes of low slump concrete that are laid with asphalt spreader machines. With an inexpensive cement, many asphalt based projects could now be converted over to a green cement concrete project.

Green Concrete USA Testing with an ENR Top Ten Reedy Mix Company

A large company listed on the New York Stock Exchange has ready mix operations in 11 states. That company preformed extensive testing on GREEN CEMENT in 2007 and 2008. Fly ash was tested from five different power plants located in five different states. They retained the services from the number one concrete lab in that state. The testing was extensive, and included freeze-thaw, durability, and other long term testing. The GREEN CEMENT passed all the requirements for durability and met the ASTM C-1157 requirements for a blended hydraulic cement. (My project with them was stopped in early 2008 when they realized that the economy was going south. I am under a confidentiality agreement with them until 2012. Testing data can be revealed once that agreement expires.)

Testing of a Lousiana Class C Fly Ash

In July of 2010, GREEN CONCRETE USA worked on a project with Big Rivers Industries in Atlanta, Georgia. Big Rivers is owned by Oldcastle. Big Rivers furnished fly ashes from the Big Cajun II power plant in Louisiana. The purpose of the testing was to see if those ashes could be used to make a GREEN CEMENT for Oldcastle to use in their precast operations. TEC Services of Atlanta was chosen to be the independent concrete testing laboratory. They preformed ASTM C 192-05 tests using Louisiana fly ashes. That ASTM test is a Standard Test Method for Making and Curing Concrete Test Specimens in the Laboratory. A Green fly ash cement replaced 100% of the Portland cement that is normally used in concrete. The concrete had 3 day, 7 day and 28 day strengths of 2,500, 4,400, and 5,900 psi. TEC Services offered to do the ASTM C-1157 certifications for us. Test results can be made available to parties interested in doing business with GREEN CONCRETE USA. Unfortunately, the power plant put the ash contract out for bids in August of 2010. In the fall, the contract was awarded to another company.

Testing of Illinois Green Fly Ash Cements

GREEN CONCRETE USA had a concrete testing facility in Ottawa, Illinois in 2009-2010. Midwest Testing in Peru, Illinois preformed the cylinder breaks. Fly ash was tested from 9 different sources. New Illinois mercury air regulations went into effect in July of 2010. These regulations greatly impacted the quality of fly ashes in Illinois. Activated Carbon (AC) was used to capture mercury. This AC ended up in the fly ash causing much of the fly ash to become unusable for concrete producers. An off-spec Illinois Activated Carbon (AC) injected fly ash was tested for use in a Green Cement and a Green Concrete. That fly ash worked very well for use as a Green Cement. Concrete cylinders made using that ash had seven day strengths of 5000 psi, and 28 day strengths of 8000 psi. The total cementious cost for that mix was $14.30 per cubic yard. A six bag standard Illinois DOT mix using $100 a ton Portland cement would have a comparable cost of around $28.20 a cubic yard. Additional testing has been done by GREEN CONCRETE USA using Expanded Polystrene (EPS) for air entraining purposes. Testing preformed by Elemix confirms the use of EPS for air entraining purposes. A great opportunity exists in Illinois for GREEN CEMENT projects and products. Fly ash is available for little or no cost at many plants and locations. Using EPS for air entraining makes these fly ashes useful.