High performance concrete (HPC) has been defined as concrete that possesses high workability, high strength (+41 MPa) and high durability.
ACI (American Concrete Institute) has defined HPC as a concrete in which certain characteristics are developed for a particular application and environment.Under the ACI definition durability is optional and this has led to a number of HPC structures, which should theoretically have had very long services lives, exhibiting durability associated distress early in their lives. ACI also defines a high-strength concrete as concrete that has a specified compressive strength for design of 6,000 psi (41 MPa) or greater.
The desired criteria of a High Performance Concrete require the presence of Fly Ash (FA) or Granulated Ground Blast Furnace Slag (GGBS) as part of the binder. This can be done most economically by adding the OPC replacement components when mixing the concrete. Another alternative - if available - would be to use pre-blended OPC containing the replacement products. The use of normal interground Pozzolanic Portland Cement (PPC) is not providing all the features required to make a High Performance Concrete which are high WORKABILITY, high STRENGTH and high DURABILITY.Even GGBS can not provide all three required features of a High Performance Concrete.
Concrete is the most widely used building material. Any improvement in the design of this material, for example, cost, durability, or strength, ripples through the economy.
"Research is focused on advancing our fundamental understanding of the rheological properties of suspensions. We are exploring how particle shape and size distribution, as well as how inter-particle forces and their manipulation, effect the properties of suspensions in both Newtonian and non-Newtonian fluids. The simulation code, which is under active development, uses a Dissipative particle Dynamics algorithm in a highly parallel implementation to study large suspension systems with up to 75,000 inclusions (suspended particles) and over one million mesoscopic fluid particles".
"The computation of inter-inclusion forces takes into account the relative velocities of the inclusions as well as the local surface curvature and surface normals at the point of interaction. The inclusions can be either spherical, ellipsoidal, or highly detailed rocks reconstructed from x-ray microtomography images of concrete samples".
(The image and text shown is part of the work of the National Institute of Standards, USA)