Table 1.

Supplementary and complementary characteristics between OPC and SCM.

Material Characteristics	OPC	SMC
Composition/source	Produced from raw materials such as limestone, clay and, to a lesser extent, minerals.	Coming from by-products or residues from industrial processes, such as coal fly ash, blast furnace slag, and silica fume, natural materials or those submitted to activation processes.
Contribution to mechanical strength	Mainly responsible for the compressive strength of cementitious matrices, with a solid and cohesive formation due to the hydration process.	They can contribute to concrete strength. Materials such as fly ash and blast furnace slag that have pozzolanic reactivity react with the calcium hydroxide released during cement hydration forming additional compounds and strengthening the concrete matrix.
Influence on durability	It provides good durability in ordinary environments; however, it has high alkalinity that can be unfavorable in aggressive environmental conditions.	They can show significant improvement in the durability of cementitious matrices in aggressive environments by increasing resistance to chloride ion penetration and enhance corrosion protection.
Sustainability	High energy and CO2 emission during clinker production.	Used to reduce Portland cement consumption, which results in less environmental impact.
Hardening time	Intense and fast hydration process.	They make it possible to delay the hardening time, seen as an advantage in certain applications.
Shrinkage	Tendency to shrink during the hardening process.	Helps reduce concrete shrinkage, due to its lower amount of hydration compounds.
Fineness and influence on reactivity	Directly related to its reactivity and hydration rate. The thinner the cement results in a faster hydration rate.	In general, finer supplementary materials have a greater pozzolanic reactivity, because they have a larger surface area available to react with the calcium hydroxide released during cement hydration. These materials can also interfere with the physical characteristics of the cementitious matrix, since they can present a filling effect.