23-09-2014, 01:02 PM
PARTIAL REPLACEMENT OF CEMENT BY USING RICE HUSK ASH ON CONCRETE
PROJECT REPORT
ON CONCRETE.docx (Size: 719.2 KB / Downloads: 16)
Abstract
This experimental work explains the effects of using Rice Husk Ash (RHA) as a partial cement replacement material in concrete. This work is based on study of concrete made with Pozzolana Portland Cement (PPC) and 5%, 10%, 15% and 20%of PPC replaced by RHA. Then various experiments were carried out to determine properties of concretes incorporating optimum RHA. Tests include compressive strength, flexural strength, split tensile strength, modules of elasticity, water permeability. These tests were carried out for7, 14 and 28 days for each percentage. The optimal level of properties of concrete made with the combinations of RHA in each percentage.
Introduction
1.1 General
Concrete is the man made material widely used for construction purposes. The usual ingredients in concrete are cement, fine aggregate, coarse aggregate and water. Concrete is considered as durable and strong material, so that it can be used for construction purpose. There for researchers around the world are directing their efforts towards developing a new material to overcome the scarcity of cement. Invention of large construction plants and to use of addictive materials to the increased use of large construction plants and equipments around the world added to the increased use of material. Cement has good binding property and widely used in all places in the world for construction and it is used as a binding agent to bind fine aggregate, coarse aggregate and other ingredients. The sizeof theFine aggregate which are all used should be less than 4.75mm and the size of coarse aggregate used should greater than 4.75mm.
Raw Material of Rice Husk Ash
Burning of RH in ambient atmosphere leaves a residue, called rice husk ash.For every 1000 kg of paddy milled, about 220 kg(22%) of husk is produced, and when this husk is burnt in the boilers, about 55 kg (25%) of RHA is generated.Rice husk removal during rice refining, creates disposal problem due to less commercial interest. Also, handling and transportation of RH is problematic due to its low density. RHA is a great environment threat causing damage to land and surrounding area where it is dumped. Therefore, commercial use of rice husk and its ash is the alternative solution to disposal problem. In this paper we have discussed a preliminary analysis of the numerous reported properties and uses of rice husk and its ash. Attempt has been made to collect data and information from various research work related to RH and RHA.Rice husk is unusually high in ash compared to other biomass fuels in the range 10-20%. The ash is 87-97% silica, highly porous and light weight, with a very high external surface area. Presence of high amount of silica makes it a valuable material for use in industrial application.
THE EFFECT OF RICE HUSK ASH ON MECHANICAL PROPERTIES
It presents that the concrete incorporating RHA had higher compressive strength, splitting tensile strength and modulus of elasticity at various ages.Also it shows that RHA as an artificial pozzolanic material has enhanced the durability of RHA concretes and reduced the chloride diffusion.Results show that concrete incorporating RHA had higher compressive strength, splitting tensile strength and modulus of elasticity at various ages compared with that of the control concrete.In addition, results show that RHA as an artificial pozzolanic material has enhanced the durability of RHA concretes and reduced the chloride diffusion.The result shows that the temperature of 650 degrees centigrade and 60 minutes burning are the best combination to obtain proper quality of RHA.The performance of concrete with cement replacement by RHA is outstanding considering resistance to water and chloride ion penetrations which are in many cases the most important characteristic concerning durability and corrosion prevention.
RICE HUSK DERIVED WASTE MATERIALS AS PARTIAL CEMENT REPLACEMENT IN LIGHTWEIGHT CONCRETE
In this study rice husk ash (RHA) and broiler bed ash from rice husk, two agricultural waste materials, have been assessed for use as partial cement replacement materials for application in lightweight concrete.Physical and chemical characteristics of RHA and BBA were first analyzed.Three similar types of lightweight concrete were produced, a control type in which the binder was just CEMI cement (CTL) and two other types with 10% cement replacement with, respectively, RHA and BBA.All types of similar lightweight concrete were prepared to present the same workability by adjusting the amount of super plasticizer.Properties of concrete investigated were compressive and flexural strength at different ages, absorption by capillarity, resistivity and resistance to chloride ion penetration (CTH method) and accelerated carbonation.Present results show that replacement with 10% RHA leads to improvement in strength and durability related properties of control lightweight aggregate concrete, an insulating material which reduces energy consumption in buildings.The use of RHA, a raw material which derives from
PROPERTIES OF MATERIALS
INTRODUCTION
This chapter deals with the study of properties of various materials like cement, fine aggregate, coarse aggregate, water, Rice Husk Ash that were used in casting of cement concrete.
FINE AGGREGATE
The sand used for the experimental program was locally procured and conformed to grading zone II as per IS: 383-1970.The sand was first sieved through 4.75 mm sieve to remove any particles greater than 4.75 mm and then was washed to remove the dust. Properties of the fine aggregate used in the experimental work are tabulated
COARSE AGGREGATE:
Locally available coarse aggregates having the maximum size of 10mm and 20mm were used in the present work. Testing of coarse aggregates was done as per IS: 383-1970. The 10mm aggregates used were first sieved through 10mm sieve and then through 4.75mm sieve and 20mm aggregates were firstly sieved through 20mm sieve.
Rice Husk Ash
Rice husk is a residue produced in significant quantity on a global basis.The use of rice husk ash in concrete was patent in the year 1924; all the researches were concentrated to utilize ash derived from uncontrolled combustion. Controlled combustion influences the surface area of RHA, so that time, temperature and environment to be considered to produce ash of maximum reactivity. Efforts have been made to burn the husks under controlled conditions and to utilize the resultant ash as building material. Rice husk ash (RHA) contains high amount of silicon dioxide. The non-crystalline phase in RHA obtained from combustion at temperatures below 600 °C consists primarily of a disordered Si-O structure
CONCLUSION
There are huge amounts of RHAproduced as by-product from the rice processing mills,mainly in developing countries, which are disposed toenvironment without any return price. Thereafter, disposal cost is increased in order to transport this ash; also alarge land area becomes useless and the fertility of land is reduced. So the problem can be solved or minimized by properly utilizing the RHA through the production ofcement or concrete as well as production of silica.Because, RHA contains a large amount of silica and also exhibits excellent pozzolanic property. In fact, incorporation of RHA either in cement or in concrete notonly fulfills the demand of cement but also makes a role inproduction of durable concrete. The strength development of concrete produced with a particular levelof RHA replacement is the same or higher as compared to OPC concrete. For about 20-30% replacement of RHA, no OPC concrete. For about 20-30% replacement of RHA, no