2.2.1 Classification Based on the Oxford dictionary brick is defined by a small rectangular block typically made of baked or sun-dried clay, used in building. The brick unit does not exceed the dimensions (mm) of 337.5x225x112.5 (LxWxT). bricks commonly made of clay, calcium silicate or cement. These types must comply with national standards, for example in America ASTM C73 (calcium silicate units), ASTM C62 (clay units) and ASTM C55 (concrete units).2.3 Clay bricks Clay bricks are made by molding suitable clay and shale into standard sized units, which are then fired at temperatures between 900 and 1200. The fired product is ceramic composed predominantly of silica SiO2 (generally between 55% and 65% by weight) alumina Al2O3 (from 10 % to 25%) combined with up to 25% other constituents (Neil et al. 2005). Clay bricks are used in a wide range of buildings, from homes to factories, and in the construction of tunnels, waterways, bridges etc. Their properties vary depending on their intended purpose, but clays have provided the basic material for construction for centuries. Brick is the oldest building material and much of its history is lost in antiquity. The oldest burned or fired bricks have been found at the sites of the ancient cities of Babylon, some of which are estimated to be around 6,000 years old. After all, brick is virtually indestructible. Table 2.1: Classification of bricks based on compressive strength and water absorption (ASTM C62) Designation Compressive strength, psi (MPa) Maximum water absorption within 5 hours of boiling, % Average of 5 bricks Individual average of 5 bricks IndividualGrade SW 3000 (20.7) 2500 (17.2) 17 20Grade MW 2500 (17.2) 2200 (15.2) 22 25Grade NW 1500 (10.3) ...... half of the paper . .....resulted in inclusion of fly ash in reducing the compressive strength of the concrete specimen. It was also reported that the reduction in the compressive strength of concrete with quarry dust was compensated by the inclusion of fly ash in the concrete mix. Reddy (2007) reported an increase in compressive strength by using quarried rock flour as fine aggregate instead of river sand. According to Abdullah MJ, the increasing percentage of quarry dust replacing sand will decrease water absorption. From this research, it is revealed that quarry dust will increase the strength of brick.2.6.4 Kenaf Fiber2.6.5 WaterWater used in concrete, in addition to cement, thus causing it to set and harden, even in mixing plants , positioning and compaction of fresh concrete. In general, potable water, such as tap water, is acceptable for mixing concrete.