RICE HUSK ASH AS A PARTIAL SUBSTITUE TO CEMENT IN CONCRETE MIX

Nowadays,
consumption of rice is increasing that leads to the greater demand in the
production of it. After harvesting and shelling, husk remains and comes in great
volume. Thus this rice husk is one of the big problems to be considered. Some
studies suggested a solution to put rice husk ash as partial substitute to
cement in concrete mixing in order to minimize the large quantity of rice husks
build up as time goes by.

Reinforced
concrete is concrete in which reinforcing bars or other types of reinforcement
have been integrated to improve one or more properties of the concrete. For
many years, it has been utilized as an economical construction material in one
form or another in buildings, bridges, and many other types of structures
throughout the world. A large part of its worldwide appeal is that basic
constituent materials-cement, sand, aggregate, water, and reinforcing bars-are
widely available and that it is possible to construct a structure using local
sources of labor and materials (Fanella, 2011).

            Structural concrete uses like
hydraulic cement, water is necessary for the chemical reaction of hydration. In
the process of hydration, the cement sets and bonds the fresh concrete into one
mass. Portland cement, which originated in England, is undoubtedly the most
common form of cement (Aghayere and Limbrunner, 2007).

            Cement as one of the main components
of concrete. And silica fume is present in cement which is very effective
pozzolanic material. It is added to Portland cement concrete to improve its
properties, particularly its compressive strength, bond strength and abrasion
resistance. Rise husk ash (RHA) is a potential source of amorphous reactive
silica. And most of the ash is used in the production of Portland cement. Rice
husk ash (RHA) produces Silpozz which is finer than cement. Silpozz has a
potential to be used as a substitute silica fume as a much lower cost. Adding
Silpozz to the concrete mix will enhance the workability, strength and
impermeability of the concrete mixes.

            Engineers nowadays are designing
structures considering some factors like its quality, safety, aesthetics and
its economic value. In order to have these designs, researchers find ways on
how to do it. Some are making changes on the design of the materials used in
construction like finding substitute to coarse aggregates; cement properties,
sand, or some are changing the design itself of the structure.

            A concrete made by sand, gravel,
cement and additional percentage of rice husk ash will be used with this
project. Two samples of concrete mix will be tested, one with a 30% rice husk
ash and the other with a natural concrete mix. This test aims to show if rice
husk ash with a 30% percentage substitute on cement in a concrete mix will pass
the compressive strength of a normal concrete mix.

By
using rice husk ash as  substitute by 30
percent in cement, this project outlines a more economical concrete mix with
the same strength or passing the strength of a natural concrete mix.