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 process can be applied to a number of supplementary materials, including 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 higher cement substitution, or an overall higher strength than pure Portland Cement.
Example 1: a Roman Cement blend with 20% class F fly ash modified for high performance
The graph below shows 3, 7, 28 and 91-day compressive strength results in concrete, at a water-to-cement ratio of 0.47, for the Roman Cement blend vs. Portland Cement and a conventional 20% class F-Fly ash blend. While the conventional blend with the untreated class F Fly ash underperforms the 100% Portland Cement mix at all ages, the Roman Cement mix significantly enhances compressive strength performance vs. pure Portland Cement at 7 days curing and beyond.
Example 2: a Roman Cement blend with 35% of combined class F Fly ash and a Natural Pozzolan
In this example we used a Roman Cement concrete mixture comprised of 65% Ordinary Portland Cement, 25% modified class F Fly ash and 10% Natural Pozzolans treated for optimal performance. The Natural Pozzolans used in this example are abundant and available throughout the world. The graph below shows the compressive strength performance of the Roman Cement blend with 35% substitution, as compared to both a 100% Portland Cement, and a conventional 70% Portland Cement / 30% Fly ash blend at a water-to-cement ratio of 0.43. The net pozzolanioc effect is very visible at later ages, and even more pronounced than in the previous example.
Example 3: a Roman Cement blend with 30% cement substitution designed for both higher early strength and strong late strength performance
This example shows a Roman Cement blend with 70% Portland Cement, 15% modified class F Fly ash, and 15% Natural Pozzolan. As in the previous examples, the compressive strength performance of the Roman Cement product was compared to a 100% Portand Cement mix, and to a 70% Portland Cement / 30% conventional class F Fly ash mix. By optimizing the modified class F Fly ash and the Natural Pozzolan, we were able to create a product that even at a 30% cement substitution level performs similarly or better than pure Portland Cement.
All mixes had a water : cement ratio of 0.44.