Historical: Ready Mix Concrete (Fly Ash) (3,000 - 4,000 psi) - 2015

Concrete is a common construction material, used in many structural applications, and is highly customizable in composition. Concrete is made by mixing cement, water, sand, and gravel, and can include chemical admixes, alone or in combination, to provide improved strength, durability, or other desired characteristic. This Common Product profile describes an in-situ/ready mix concrete composition likely to be used to produce normal weight 3,000 – 4,000 psi concrete for construction in the San Francisco Bay area, where a Portland-pozzolon blended cement (described as Type IP in ASTM C595/C595M) is used in place of a “straight mix”. The exact amounts of all ingredients in concrete will likely vary to some degree based on the contractor, concrete supplier, and the materials used by the supplier to mix the concrete ordered. The LCA excludes the environmental impacts associated with the use of admixtures, due to the high variation in the amount and type used across concrete mixes. To assess the potential influence this exclusion could have on the impact of the concrete, a scenario analysis was conducted with median amounts of four categories of admixtures: retarding, accelarating (chlorinated), accelerating (non-chlorinated), and water reducing/retarding. Results showed that despite the small contribution by mass (<1%), use of admixtures could increase the environmental burden. Eutrophication potential in paticular was affected, increasing the burden of concrete by as much as 17%. Primary energy demand also increased significantly, up to 7%, while global warming potential showed increases up to 4%.

A more up to date Common Product is available here: Ready Mixed Concrete (Structural, NWC 3000-4000 psi).