What is mortar made of?
In connection with building, the term mortar appears again and again. Everyone knows the term, but what exactly does the material consist of?
Mortar consists of these ingredients
The building material is a mixture of a binder and a so-called aggregate. Usually mortar consists of water and these two substances and often from a surcharge. But there are also mortars that consist only of water and binder and those that contain no water, but a chemical hardener. This is usually the case with synthetic resin mortar.
The aggregate can be sand, fine gravel up to a grain size of four millimeters, but also brick or concrete. The grain gives the mortar the necessary mass.
The binder is, for example, cement, lime, hydrated lime, synthetic resin or another substance. Its most important property is to harden through a chemical reaction. So mortar does not harden because the water contained in it evaporates, but because chemical processes take place.
The aggregates change the properties of the mortar. They can accelerate or slow down the chemical reaction or influence the finished building material. Mortars, which are locally referred to as food, may have different names depending on their purpose or composition. Fire protection mortar is named after its use. For example, it protects wall breaches against fire. Lime mortar consists of sand and slaked lime or gypsum mortar containing sand and gypsum.
The origin of the building material
Opus caementicium (cast brickwork) is a building material that the Romans used in antiquity to build water pipes, foundations and large structures. The composition is identical to mortar. The material consisted of stones, sand and burned limestone, it is similar to the lime mortar. An addition of pozzolana changed the material. It cures with the addition of water and makes it possible to produce artificial stones. The material consists of silica, limestone, clay, iron oxide and various alkaline substances and is found in nature among other things in volcanic ash. Mortar with pozzolana is the cement of ancient times.
It is known that the Phoenicians used mortar made of pozzolana around 1300 BC to plaster masonry or to put stones together. Simple mortar to brick walls was already known 14,000 years ago in the region of today's Turkey. But this did not cure, but served only to fill in gaps which were unavoidable in the masonry of natural stones.
The knowledge of the Phoenicians reached the Greeks and the Romans. But it was lost in the turmoil of the migration of peoples. Therefore, mortar was largely unknown in the Middle Ages in Europe. It was not until 1,700 AD that it was possible to produce hard mortar and concrete again.
Today, mortar is indispensable in construction. It is used for joining bricks and for plastering masonry and ceilings. Each building usually has different types of mortar.