1.0 1.1 NTRODUCTION
Concrete is a composite element consisting of aggregates enclosed in a matrix of cement paste including possible pozzolanic, has two major components-cement paste and aggregates. As a construction material, concrete can be in almost any shape desired, and once hardened, can become a structural (load bearing) element. The strength of concrete depends upon the strength of these components, their deformation properties, and the adhesion between the paste and aggregate surface. With most natural aggregates, it is possible to make concrete up to 120KN/mm2 a compressive strength by improving the strength of the cement paste, which can be controlled through the choice of water-cement ratio, and type and dosage of admixtures (Dwivedi 2006).
The high cost of conventional construction material is a dominating factor affecting housing system around the world. This has necessitated research work into alternative materials in the construction field. Since the cost of cement is many times more than the cost of other ingredients in concrete making. Recently, attention is mainly directed to use of as little cement as possible constituent with adequate strength and durability. Little research has been carried out to study the bamboo leaf waste as a pozzolanic material. Dwivedi (2006) reported the reaction between calcium hydroxide (CH) and bamboo leaf ash for four hours of reaction using the differential scanning calorimetric (Dsc) technique. Singh et al (2000) discussed that eco friendly composite cements may be obtained by partial replacement of Portland cement (PPC) with low cost materials. They studied the hydration of bamboo leaf ash in a blended Portland cement. It was concluded that bamboo leaf ash is an effective pozzolanic materials. When 20 weight (wt) % of bamboo ash was mixed with PPC the compressive strength values of mortars at 28 day of hydration were found to be quiet comparable to those of PPC. Villar-cocina et al (2010) conducted a study on sugarcane leaf ash (SCLA). Hydration of 10 wt % SCLA composite Portland cement was studied by using powder x-ray diffraction, FTIR spectroscopy, and differential scanning calorimetric and other techniques. The result have show that the pozzolanic reaction of sugarcane leaf ash increases with time. They have been used to produce concrete having almost the same behavior as normal concrete.