The Ezillo Pyroclastic rocks studied for this project occurs as an extrusive igneous body within sedimentary rocks of Turonian age. They are magma that emplaced onto the surface of the earth as coherent lava flows or as fragmental deposits from extrusive or volcanic rocks Hoque.
The study area covers Ezillo, Isimkpuma and Nkalagu, all in Ebonyi State, southeastern Nigerian. The area covers about 81 square kilometers. The people of Ezillo and its environs belong to the Igbo speaking ethnic group, however with a prevalent of Abakaliki dialect. The major occupation of the people living in the area are farming and trading.
The study area belong to the Eze Aku Formation and consists of basal sandstone (Isimkpuma sandstone) overlain by bioturbated siltstone (Ezillo siltstone) and calcareous black shale with interbedded tabular bioclastic limestone (Nkalagu limestone) at the top. The Eze Aku Formation was identified as a shallow marine sequence (Sampson, 1954; Reyment, 1981).
The Ezillo pyroclastic rock is among the best – known occurrence of volcanic rocks in Nigeria (Okezie, 1965). This pyroclastics rock is used in construction company in constructing of roads, bridges and building. The Ezillo area (in Ebonyi State Nigeria records occurrence of dark grey pyroclastic rocks intercalated with sandstone, limestone, shale and siltstone. Although these pyroclastics continue to be widely used for important engineering construction works, little or no work has been done to evaluate their engineering properties. This stems partly from the fact that these rocks, in terms of aggregates have performed fairly well in the field, and partly because substitutes are either too expensive or rare.
This project is aimed at creating more deserved attention on engineering characteristics of Ezillo pyroclastic rock. The analysis that was conducted on the Ezillo pyroclastic rocks helped to determine the physical and the chemical properties of the rocks as construction material.
STATEMENT OF PROBLEMS ON Pyroclastic Rocks
The research intends to provide answers to the following research questions.
v Are the pyroclastic rocks in the Ezillo area appropriate as construction materials for projects such as building, dam, roads and bridges?
v Do the geotechnical properties of pyroclastics rock meet the standards for construction material?
v What are environmental factors controlling the behaviour of the pyroclastic rocks in construction projects?
v What are the possible ways of improving the quality of pyroclastic rocks to make them meet the standard, if found not to meet the standards for construction material?
v Is the mechanical strength sufficient enough to bear the load resulting from these engineering structures?
v Are the pyroclastics suitable for the construction of all engineering project?
LOCATIONS, EXTENT AND ACCESSIBILITY
The study area Ezillo and environs lies on the southern part of the Benue Trough and on the Western limb of the Abakaliki Anticlinorium. It covers the area between longitude 7O45E and 7O501E and latitude 6O301N and 6O251N. The Abakaliki – Enugu high-way and Ezillo – Nkalagu junction and foot-paths could help in traversing the area and locating the outcrops and villages within the area. The villages within the study area include Ezillo, Nkalagu, Edema and Imoha.