Clay bricks durability

A stucco of lime mortar will protect the sides. Mud can also be made into unfired bricks for "lump-wall" construction, but unless you have a suitable clay-containing soil, lime or cement must be added to make the bricks durable. 

In Egypt the dried clay bricks without burning were hnked with Nile slim (2). Such construction was effective in dry climatic zone only, because low moisture durability of these materials. Also the blocks in first stairs Djoser s pyramid were linked with clay (twenty seventh century before Christ) in Sakkara [2]. 

Kung, J. H., Frost Durability Study on Canadian Clay Bricks III. Characterization of Raw Materials and Burnt Bricks, Durability of Bldg. Mater., 5 125-143 (1987)... 

Other applications of ceramics require clay, either raw or purified, sand, and feldspar. Brick, porcelain, and white wares are made from these raw materials the main expenditure in making these products is in firing the mixtures of powders to a dense solid. Ordinary brick made from fire-clay requires a small amount of energy even refractory brick for high temperatures and chemical durability, made partly from purified oxides such as alumina or chrome ore,... 

Mortar (sometimes called cement) is used to bond surfaces like bricks together, but also for plastering walls. Historically, it has been composed variously of lime, sand, clay, volcanic rock and ash, brick dust, and potsherds. Early lime mortars that set simply by reaction between the lime and carbon dioxide in the air offered little protection from deleterious effects of water to the structure. Aggregate mortars that incorporatepozzolans and silicates, which react to bond with calcium, do not need C02, and some can even set underwater. These are called hydraulic mortars, and offer durability in weather, but are less suitable for situations where plasticity is needed, as in restoration projects, for example. 

The presence of quartz in significant amounts gives strength and durability to a brick. This is because, during the vitrification period, quartz combines with the basic oxides of the fluxes released from the clay minerals on firing to form glass, which improves the strength. However, as the proportion of quartz increases, the plasticity of the raw material decreases. 

Although bricks may be made of many materials, the term brick masonry is normally applied only to that type of construction employing comparatively small units of burned clay or shale. Ordinary brick is economical, and, when hard burned and laid in good mortar, it is one of the most durable construction materials available for buildings. 

Common brick, also known as hard or kUn-run, is made from ordinary clay or shale and is fired in the usual manner. Overburned bricks, called clinkers, are unusually hard and durable. 

Water suction affects the quality of the final material and its durability significantly. High values should be avoided, since they can cause pieces with defects and lower durability. The substitution of FW by OW or OWW and forming method affected water suction values of bricks. Water suction decreased when the bricks are formed by pressure. (Table 4). Clay mixed with FW showed a water suction of 2.43 and 2.31 kg/m min for extruded and compressed bricks, respectively. Replacement FW by OW or OOW waste produced a decrease in the water suction, being the most pronounced decrease when OOW is used as... 

The performance of clay-based construction products, e.g., bricks and roofing tiles, can be monitored using thermal methods. The types of raw materials, viz., clay and accessory minerals, and their reactions that occur during the firing process and the durability of clay products can be examined through the application of DTA, TG, TMA, and dilatometric methods. This is particularly important for quality control as physical and chemical behaviors are dependent on the raw material characteristics, e.g., composition, particle size, and morphology. 

The relationship between saturation coefficient and absorption reflects both the quality of the brick and the history of the brick, e.g., the starting raw material composition (clay minerals, quartz, calcite) and the firing condition (Fig. 24). These factors are conveniently identified and estimated by thermal techniques as already discussed. For each raw material, a rational durability index should be defined in terms of absorption and saturation coefficient. The appropriate index can be determined for quality control as the raw material changes. 

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