The common materials of masonry construction are brick, concrete block and natural stone such as granite, marble, travertine or limestone, etc. Masonry is generally a highly durable form of construction and it is commonly used for the walls of buildings, retaining walls and monuments. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either weight-bearing. Concrete blocks, especially those with hollow cores, offer various possibilities in masonry construction. They generally provide great compressive strength and are best suited to structures with light transverse loading when the cores remain unfilled.

 

Brick - is a block of ceramic material used in masonry construction, usually laid using mortar. Bricks may be made from concrete, clay, shale, calcium silicate, soft slate or shaped from quarried stone. Clay is the most common material, with modern clay bricks formed in one of three processes - soft mud, dry press, or extruded.

 

Hardness of Bricks - There are many different types of bricks and different scales of hardness. The strength of a unit is used to determine its durability and cutability. Both compressive strength and absorption are affected by properties of the clay and method of manufacturing and degree of fired. Most bricks have a strength ranging from 3,000 PSI to over 20,000 PSI with the average being around 10,000 PSI. Also different type, size and volume of aggregates in the mixture can further strengthen the hardness of the bricks.

 

Fire Brick or Refractory Brick - It starts with the fireclay is baked in the kiln until it is partly vitrified and for special purpose may also be glazed. Fire bricks usually contain 30-40% of aluminium oxide or alumina and 50-80% of silicon dioxide or silica. They can also be made of chamotte and other materials. For bricks of extrem refractory character, the aluminum oxide content can be as high as 50-80% and silicon carbide may be present. The silica firebricks that line steel-making furnaces are used at temperatures up to 1650 degree which would melt many other types of ceramic and in fact part of the silica firebrick liquefies.

 

Concrete Block - In the United States, concrete block, cement block or foundation block are generically known as Concrete Masonry Units (CMU). Concrete blocks are made from cast concrete, cement and aggregate (usually sand) and fine gravel for high-density blocks. Lower density blocks may use industrial wastes as an aggregate. Those that use cinders such as fly ash or bottom ash are called cinder blocks. Clinker blocks are use clinker as aggregate. Lightweight blocks can also be produced using aerated concrete. Furthermore, cinder and concrete blocks typically have much lower water absorption rates than brick. They often are used as the structural core for veneered brick masonry, or are used alone for the walls of garages, factories and other industrial style buildings. Concrete blocks may be produced with hollow centres to reduce weight or improve insulation. Concrete block, when reinforced with concrete columns and tie beams or steel rebars, is a very common building material for load-bearing walls of buildings, in what is termed Concrete Block Structural (CBS) construction.

 

Stone Masonry - Stone blocks used in masonry can be dressed or rough. Stone masonry utilizing dressed stones is known as ashlar masonry, where as masonry using irregularly shaped stones is known as rubble masonry. Both Rubble and ashlar masonry can be laid in courses through the careful selection or cutting of stones. Natural stone venners over CMU or tilt-up concrete walls are widely used to give the appearance of stone masonry. Sometimes river rock is used as veneer. This type of material is not favored for solid masonry as it requires a great amount of mortar and can lack intrinsic structural strength. Manufactured stone (cultured stone) veneers are became more popular than the natural stones and are typically made from concrete.