CHAPTER ONE
1.0 INTRODUCTION
This
project deals with the design and production of ceiling board using Plaster of
Paris [POP] gypsum materials. Plaster of Paris [POP] is a white powdery mixture
of gypsum. It has been named such because the first deposit of gypsum was found
in Paris. This powder when mixed with water solidifies, but without losing its
volume. During manufacturing process, the gypsum is heated and as such, it does
not necessarily require any high heat treatment like ceramics and clays
[Worrall 1999]. Because of its property to harden with just water, it is used
in a number of areas, but most notably for molding decorative objects.
According
to Cornelis and Hurlbut (1985), plaster results from the calcinations of gypsum
(CaS04.2H20), which partially dehydrates to produce a
hemi-hydrate (CaS04.1/2H2O).
Although plaster of Paris a widely used today: its origin dated 9,000 years old
and were found in Amotolia and Syria. It is also know fact those 5000 years
ago, the Egyptians burnt gypsum in open-air fire, then crushed it into powder
and finally mixed with water to make jointing material for the blocks of
monuments, used model of plaster taken directly from the human body.
1.1 LITERATURE REVIEW
Plaster
is one of the oldest known synthetic building materials: it was used by the
Egyptians at least 4000 years ago in the construction of the pyramids, and the
Greeks were producing decorative plaster work by 500 BC. The chemistry of the
conversion of gypsum to plaster was also investigated early on by chemists such
as Le Chatelier (1850 – 1936) and van’t Hoff (1852 – 1911).
Plaster
is made by heating gypsum (CaSO4.2H2O) powder, thus converting it to calcium
sulphate hemihydrate (CaSO4.½H2O). The hemihydrate is also known as stucco or
Plaster of Paris. Probably so named because of the very large deposit of pure
gypsum found beneath Paris. When water is added to the stucco, the material
rehydrates to give a solid mass of gypsum. This rehydration is accompanied by
an increase in temperature and a slight expansion of the plaster, causing the
gypsum to perfectly fill a mould.
2.0 RESEARCH
AIM AND OBJECTIVES
The aim of this project is to design
and produce ceiling board using Plaster of Paris (POP) gypsum materials.
The
objectives of the study are highlighted below:
v
To produce durable light weight building material for
ceiling
v
To determine the strength of the ceiling board
v
To determine its durability.
v
To determine the volume and density of the ceiling board.