ASSESSING THE EFFECT OF GEOMETRIC PROPERTIES (SHAPE) ON THE STRENGTH OF INTERLOCKING PAVING STONE

ABSTRACT
Interlocking paving stone is a good surface material produce as a result of mixture of aggregate to produce a good workability surface.
This research work investigates on how the shapes affect the strength after production.

The materials used include cement, sharp sand, quarry dust or granite dust and water.
The structural engineering properties investigated include compressive strength, flexural strength of each types of interlocking paving stone produced that is 3 Star, Double T, Land Roman, Bubble Glover and Didalo tiles respectively.

The mix ratio of each stone was also investigated as well as the rate of crushing of the paving stone were noted.
So, from the observation made from this project the average strength of the interlocking paving stone was found to be 5.7gN/mm2 and the highest strength received was found to be that of Bubble glover with a maximum strength of (6.39 N/mm2). While that of Double T (5.59N/mm2), 3 Star (5.39N/mm2), Land Roman (5.30N/mm2) and Digalo (5.19N/mm2)

CHAPTER ONE
1.1 Introduction
Researchers have work on various materials for paving and method of pavement construction that will provide adequate support for traffic load with minimum construction cost and maintenance.

The concept of interlocking stone pavers dated back over 200years ago to the Roman empire where over 800,000km of roads were built using interlocking paving blocks.

The roman developed a simple system for building roads some of the roads are still in use today.

The roads were constructed with a well compacted base of lime and gravel covered with a tight fitting cut stone which produced an excellent and economical roadway that remained virtually maintenance free in all types of weather (Wilford, 1994).
The elements are laid directly on a bedding sand layer with edge restraints to allow block layer to develop limited load spreading capacity to keep bond together at great mass and strength (Wilford, 1994).
Investigation has not been intensified on the use of paving stone for pavement unlike surface dressed concrete pavement structures. The potential of different types of paving stone for pavement structure used as car park or foot paths.
In developing countries paving stone are used for the construction of paved area on a large scale.

The material use in paving stone are of different variety of colours and shapes which are most likely have effect on the strength of the stone, they create unique and creative patterns while providing a surface that is durable and functional (Akinyemi, et al, 1992).
It is observed that various shapes of these paving stone are produced and widely used in our locality.

These include: roman, zenith, double T, 3 star etc. And the laying pattern include, stretcher, running, digalo, bubble glover, diagonal, Herringbone and parquet bond but in lieu of this, different materials and mix ratio are used in order to determine various strength and durability of the paving material. (Shackel, 1990).
Some use dust from quarry with sharp sand and granite of specified size while others prefer using stone dust with granite only but the most commonly used are dust from quarry only.

During laying some prefer placing the elements over a graded sand base and interlocked with bedding and joint sand.

The jointing sand allows the pavers to interlock and structurally function as one durable layer while others use dust (Sambawa, 2010).
All those variations in materials and production account for variations in properties, quality and strength and it is therefore necessary to carry out a research work to know whether the shapes of the stone has any effect on the strength.
1.2 Aim and Objectives of the Project
The aims of this project is to determine the followings:
i. To determine the strength of the stone
ii. To know whether the shapes of the stone has any effect on the strength
iii. To educate student on what they can lay their hand on after graduation.
1.3 Justification of the Study
Due to the versatile indestructible nature of paving stone or tiles, they have been used for about every conceivable application such as residential and commercial garage floor etc.

There is need for indepth study of this interlocking paving stone as to why the sudden crack or breakdown of the stone pavers.