Russia's risky tank strategy: Cement armor raises concerns
A recently published report from the Russian research institute NII Stali indicates that Russians, facing significant equipment losses and a chronic shortage of high-quality equipment, have decided to experiment with the construction of reactive armor (ERA) by adding cement and sand.
NII Stali, or the Scientific Research Institute of Steel, conducted an analysis on experimental tests of armor in which a mixture of sand and Portland cement was added. Their intended function was to absorb part of the kinetic energy in case of impact and serve as an additional element to disperse explosion energy.
Cement and sand in Russian tanks
In theory, the Russians are attempting to enhance the effectiveness of the cheapest and most readily available forms of vehicle protection—particularly in the context of mass-produced T-62 and T-72 tanks and armored personnel carriers. In practice, however, these "reinforcements" do not compare to the classic explosive charges used in modern ERA modules.
Sand and cement do not detonate and only minimally dampen the impact of a projectile or shrapnel, making the modification at best a half-measure, and at worst, an illusion of protection. Replacing the classic equipment of ERA modules with these materials could transform a tank or armored vehicle into a deadly trap for the crew. This solution not only reduces protection effectiveness but also demoralizes soldiers who understand that their chances of surviving against modern weaponry are drastically diminished.
It is also concerning that these solutions are not solely confined to laboratory research. Experts observing the battlefield in Ukraine have noted that makeshift "concrete" armors have indeed appeared on Russian vehicles. Some of these structures closely resemble reactive armor but are actually decoys filled with construction mixtures.
This entire situation sheds light on the quality of Russian logistics and the challenges in supplying modern components. If sand and cement are being used to replace advanced composite materials and explosive charges in ERA armor, not only does it compromise protection effectiveness, but it also demoralizes crews aware that their survival odds against modern weapons are significantly lowered.
NERA as a chance for enhancing tanks?
The current crisis in Russia's armored forces is also pushing its engineers to develop new types of non-explosive reactive armor, or NERA. This is a modern type of armored vehicle protection that—unlike classic ERA—does not utilize explosive charges.
NERA operates on the principle of mechanical reaction of material layers to impact. It consists of a multi-layered structure, usually made up of metal plates and flexible inserts, such as rubber, plastics, or special composites. When a projectile strikes such armor, the flexible layer between steel plates undergoes rapid compression and expansion. This causes dynamic displacement of the outer layers, disrupting the stability of the cumulative jet or penetrator core and significantly reducing its piercing capability.
The primary advantage of NERA is the absence of explosions. This type of armor can be used on vehicles operating in close proximity to their own units—infantry, support vehicles, or in urban environments—without the fear of detonation side effects. It also simplifies maintenance and transportation, as NERA is not considered an explosive material.
This technology is gaining broader applications in NATO armies, and elements of it can be found in, among other places, Israeli Merkava tanks, modern variants of the Abrams, and European projects like the Leopard 2A7. Interestingly, NERA solutions are also being developed in the Ukrainian defense industry. Based on battlefield experiences, local engineers are seeking effective alternatives to classic ERA, which can be unreliable when targeted by drones or tandem warheads.
