The Roman Cement technology is built on particle size optimization of individual components in a blend of cement or ground clinker and supplementary materials. The technology can be used with a number of supplementary materials, such as blast furnace slag, coal ash, natural pozzolans, limestone, steel slag, and other materials that contain, silica, alumina and / or calcium oxide. 

Roman Cement has conducted extensive testing of binary blends (cement + one supplementary material) and ternary blends (cement + two supplementary materials).  By modifying the particle size distribution, a Roman Cement blend can be designed to attain specific performance attributes, such as increased early strength, or very high cement substitution, or an overall higher strength than pure Portland Cement.

Performance Results

Example 1: high cement substitution of 70% - a ternary blend with good early and late strength

 

In this example, we tested a blend comprised of 30% cement, 50% blast furnace slag and 20% class F fly ash. The objective of this blend was a high amount of cement substitution (70%) while maintaining excellent compressive strength results that are close or equivalent to those of an Ordinary Portland Cement. 

The graph below shows 3, 7 and 28-day compressive strength results as per ASTM C109 at a water : cement ratio of 0.48 for the Roman Cement blend (particle size optimized) vs. an ordinary blend with the same materials and proportions, but not particle size optimized, and pure Portland Cement.  

Example 2: 35% cement substitution in a binary blend with a focus on early strength

 

This example shows compressive strength performance for a Roman Cement binary blend comprised of particle size optimized fractions of cement (65%) and a class F fly ash (35%). All mixes were tested at a water : cement ratio of 0.35. As can be seen in the graph below, early strength in the Roman Cement blend is at the same level or higher than the result obtained with a 100% Portland Cement mix. 

Example 3: 20% cement substitution in a binary blend with a focus on all-around high performance

 

The Roman Cement technology can not only be used to achieve high cement substitution rates while maintaining similar strength performance as in pure Portland Cement. This example shows how particle size distributions can also be adjusted to create blends with a significantly higher performance than Portland Cement. The test results below show two 80% cement - 20% class F fly ash blends with two different particle size distributions designed to yield a high and an ultra-high perfromance as compared to a 100% Portland Cement material.

All mixes had a water : cement ratio of 0.35.

Example 4: a Roman Cement blend that closely mimics OPC performance

 

Roman Cement is flexible enough to be able to design blends with different cement substitution levels that perform just the same way as stand-alone Portland Cement, but with a lesser carbon footprint. This makes it easy to take a "plug-and-play" approach where a concrete producer can substitute regular cement with a Roman Cement blend and keep everything else the same. The graph below shows the compressive strength at various curing ages of two binary Roman Cement "plug-and-play" blends, one with 20% class F fly ash, and another with 35% class F fly ash, compared to the perfromance of Ordinary Portland Cement.

All mixes had a water : cement ratio of 0.35.