THE ROLE OF NATURAL POZZOLANS IN SANDCRETE PERFORMANCE


THE ROLE OF NATURAL POZZOLANS IN SANDCRETE PERFORMANCE

CHAPTER ONE INTRODUCTION

1.1 BACKGROUND STUDY  

Various research works have been carried out on the binary blends of ordinary Portland cement with different pozzolans in making cement composites.

The need to reduce the high cost of Ordinary Portland Cement in order to provide accommodation for the populace has intensified research into the use of some locally available materials that could be used as a partial replacement for Ordinary Portland Cement (OPC). Supplementary cementitious materials have been proven to be effective in meeting most of the requirements of durable concrete and blended cement is now used in many parts of the world (Bakar 2010).

The cost of building materials nowadays is so high in some parts of the world particularly developing countries like Nigeria, that only the government, industries, business cooperation, and a few individuals can afford it. This high and still rising cost can however be reduced to a minimum by the use of alternative building materials that are cheap, locally available, and bring about a reduction in the overall dead weight of the building. Some industrial and agricultural products that would otherwise litter the environment as waste or at best be put into only limited use could gainfully be employed as building material (Oluremi 1990).

Rice husk which is an agricultural by-product is abundantly available all over the world. Most of the rice husk, which is obtained by milling paddy, is going as waste materials even though some quantity is used as bedding material, fuel in boilers, etc. its ash, which not only occupy large areas causing space problems but also cause environmental pollution. Thus the concrete industry offers an ideal method to integrate and utilize a number of waste materials, which are socially acceptable, easily available, and economically within the buying powers of an ordinary man. The presence of such materials in cement concrete not only reduces carbon dioxide emission but also imparts significant improvement in workability and durability. In the present investigation, a feasibility study is made to use Rice Husk Ash as an admixture to already replaced Cement (Portland Pozzolana Cement) in Concrete.

 With increasing industrialization, the industrial by-product (waste) is being accumulated to a large extent leading to environmental and economic concerns related to this disposal. The concerns of our global environment and increasing energy insecurity have led to increasing demand for renewable energy and their sources among the resources, biomass resources (forestry and agricultural wastes) and power fuelled by them as a promising source of renewable energy with economically low operational cost.

  Rice Husk Ash (RHA) which is an agricultural by-product has been reported to be a good pozzolan by numerous researchers. Sandcrete blocks comprise natural sand, water, and binder. Cement, as a binder, is the most expensive input into the production of concrete blocks. This has necessitated producers of sandcrete blocks to produce blocks with low OPC content that will be affordable to people and with many gains. The poverty level amongst West African Countries and particularly Nigerian has made these blocks widely acceptable among the populace so as to minimize the cost of construction works. The improper use of these blocks leads to microcracks on the walls after construction. The use of alternative cheaper local materials as stabilizers will greatly enhance the production of sandcrete blocks with the desired properties at low cost. It will also drastically reduce the cost of production and consequently the cost of construction works (Cordeiro 2009).

A survey by the raw materials research and development council of Nigeria on available local building materials reveals that certain building materials deserve serious consideration as substitutes for imported ones. A few of these materials include: cement/lime stabilized bricks /blocks, sundried (Adobe) soil blocks, burnt clay bricks/ blocks, cast-in-situ walls, rice husk ash (RHA), mud and straw, lime, and sandcrete blocks. 

In the urban and rural areas of Nigeria, local milling is being done mostly by women. They mainly use firewood as a heat source and as such one hundred percent of the rice husk from the mill is a waste. It occupies 20 –24% of the rough rice produced, although the ratio differs by variety. About 108 tonnes of rice husks are generated annually in the world.

In Niger State in Nigeria, about 96,660 tonnes of rice grains were produced in the year 2000. In developing countries like Nigeria, proper utilization of agricultural waste has not been given due attention. The rice husk thereby constitutes an environmental nuisance as they form refuse heaps in the areas where they are disposed of the use of rice husk ash as a partial replacement to cement will provide an economic use of the by–product and consequently produce cheaper blocks for low-cost buildings.

Rice is a major food crop in many regions of the world. Global rice production in 2007 was approximately 638 million tonnes and Malaysia’s contribution was 2.2 million tonnes [Food and Agriculture Organisation for the UN, 2008]. Due to global demand, rice production is expected to grow from year to year. Rice husk (RH) is the outer covering of the rice grain and is obtained during the milling process. Rice Husk constitutes 20% of the total rice produced [G. Giaccio 2007].

 As a renewable material, the use of Rice Husk can eliminate waste disposal and support environmental protection. Even though Malaysia is not a prominent rice-producing country, large quantities of Rice Husk are produced every year after the harvest season (November to March). Commercially, other applications of Rice Husk are silicon carbide whiskers to reinforce ceramic cutting tools and as aggregates and fillers for concrete and board production. However, most of this agricultural by-product is simply disposed of, thus representing an environmental problem.

Rice hulls (or rice husks) are the hard-protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material (Wikipedia.com).

The phenomenal pace of population growth and urbanization drives the cement requirement to many folds. The quantum jump in the production of cement results in the alarming level of release of CO2 to the atmosphere. One way of addressing this issue is to reduce the CO2 emission from the cement manufacturing process by replacing cement with locally available by-products which are pozzolanic in nature.

Pozzolan is a siliceous or siliceous and aluminous material which, in itself, possesses little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties (Mehta, 1987).

 Also, the high cost of cement used as a binder in the production of mortar, sandcrete blocks, and concrete has led to a search for alternatives. In addition to cost, high energy demand, and emission of CO2 this is responsible for global warming. The depletion of limestone deposits is a disadvantage associated with cement products.

 Research on alternatives to cement has so far centered on the partial replacement of cement with different materials.

1.2 Rice Hull (or Husk) Ash as a Pozzolan

Rice hulls (or rice husks) are the hard-protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as a building material, fertilizer, insulation material, or fuel (Wikipedia.com).

1.3 Production

Rice hulls are the coatings of seeds, or grains, of rice. To protect the seed during the growing season, the hull is formed from hard materials. The hull is mostly indigestible to humans.

Winnowing used to separate the rice from hulls is to put the whole rice into a pan and throw it into the air while the wind blows. The light hulls are blown away while the heavy rice falls back into the pan. Later pestles and a simple machine called a rice pounder was developed to remove hulls. In 1885 the modern rice hulling the machine was invented in Brazil. During the milling processes, the hulls are removed from the raw grain to reveal whole brown rice, which may then sometimes be milled further to remove the bran layer, resulting in white rice.

 1.4 Uses of Rice Hulls Combustion of rice hulls affords rice husk ash (acronym RHA). This ash is a potential source of amorphous reactive silica, which has a variety of applications in materials science. Most of the ash is used in the production of Portland cement when burnt completely, the ash can have a Blaine number of as much as 3,600 compared to the Blaine number of cement between 2,800 to 3,000, meaning it is finer than cement. Silica is the basic component of sand, which is used with cement for plastering and concreting. This fine silica will provide very compact concrete. The ash also is a very good thermal insulation material. The fineness of the ash also makes it a very good candidate for sealing fine cracks in civil structures, where it can penetrate deeper than the conventional cement-sand mixture.

A number of possible uses for RHA include absorbents for oils and chemicals, soil ameliorants, a source of silicon, insulation powder in steel mills, as repellents in the form of "vinegar-tar" release agent in the ceramics industry, as an insulation material.

1.5 ENVIRONMENTAL IMPACT

The majority of rice husk goes into landfills since the burning in open piles is not acceptable due to environmental constraints.  This makes the research on the potential uses of rice husk and rice husk ash of primary importance in the USA and around the world.  The manufacturing of cement produces carbon dioxide (CO2), which is a prime contributor to global warming.  Typically, cement production results in CO2 emissions of about 0.8 – 1.2 tonnes/tonne of cement product depending on the production process and the fuel used.  Also, using RHA in concrete will help to reduce the amount of cement due to the partial substitution of cement by RHA and by making the concrete last longer (Folliard K.J 2002)

1.6 AIM OF THE STUDY

The aim of this research is to enhance the understanding of the role of natural pozzolans in sandcrete performance and to see how pozzolanic material would replace cement in the near future.

1.7 OBJECTIVES OF THE STUDY                         

1) To enlighten people on rice husk Ash pozzolan Carryout a cost comparative analysis to ascertain the affordability and sustainability of rice husk ash.

2) To investigate the effectiveness of using naturally occurring pozzolan materials as an additive or substitute for cement in sandcrete mixtures.

3) Carry out an analysis to ascertain the affordability and sustainability of rice husk ash.

1.8 SCOPE OF STUDY

This research work examined the use of Rice Husk Ash as a partial replacement for Ordinary Portland Cement in concrete. It involved the determination of workability and compressive strength of the sandcrete at different levels of replacement. 

 

.

THE ROLE OF NATURAL POZZOLANS IN SANDCRETE PERFORMANCE



TYPE IN YOUR TOPIC AND CLICK SEARCH.






RESEARCHWAP.ORG

Researchwap.org is an online repository for free project topics and research materials, articles and custom writing of research works. We’re an online resource centre that provides a vast database for students to access numerous research project topics and materials. Researchwap.org guides and assist Postgraduate, Undergraduate and Final Year Students with well researched and quality project topics, topic ideas, research guides and project materials. We’re reliable and trustworthy, and we really understand what is called “time factor”, that is why we’ve simplified the process so that students can get their research projects ready on time. Our platform provides more educational services, such as hiring a writer, research analysis, and software for computer science research and we also seriously adhere to a timely delivery.

TESTIMONIES FROM OUR CLIENTS


Please feel free to carefully review some written and captured responses from our satisfied clients.

  • "Exceptionally outstanding. Highly recommend for all who wish to have effective and excellent project defence. Easily Accessable, Affordable, Effective and effective."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "I saw this website on facebook page and I did not even bother since I was in a hurry to complete my project. But I am totally amazed that when I visited the website and saw the topic I was looking for and I decided to give a try and now I have received it within an hour after ordering the material. Am grateful guys!"

    Hilary Yusuf, United States International University Africa, Nairobi, Kenya.
  • "Researchwap.org is a website I recommend to all student and researchers within and outside the country. The web owners are doing great job and I appreciate them for that. Once again, thank you very much "researchwap.org" and God bless you and your business! ."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "Great User Experience, Nice flows and Superb functionalities.The app is indeed a great tech innovation for greasing the wheels of final year, research and other pedagogical related project works. A trial would definitely convince you."

    Lamilare Valentine, Kwame Nkrumah University, Kumasi, Ghana.
  • "I love what you guys are doing, your material guided me well through my research. Thank you for helping me achieve academic success."

    Sampson, University of Nigeria, Nsukka.
  • "researchwap.com is God-sent! I got good grades in my seminar and project with the help of your service, thank you soooooo much."

    Cynthia, Akwa Ibom State University .
  • "Sorry, it was in my spam folder all along, I should have looked it up properly first. Please keep up the good work, your team is quite commited. Am grateful...I will certainly refer my friends too."

    Elizabeth, Obafemi Awolowo University
  • "Am happy the defense went well, thanks to your articles. I may not be able to express how grateful I am for all your assistance, but on my honour, I owe you guys a good number of referrals. Thank you once again."

    Ali Olanrewaju, Lagos State University.
  • "My Dear Researchwap, initially I never believed one can actually do honest business transactions with Nigerians online until i stumbled into your website. You have broken a new legacy of record as far as am concerned. Keep up the good work!"

    Willie Ekereobong, University of Port Harcourt.
  • "WOW, SO IT'S TRUE??!! I can't believe I got this quality work for just 3k...I thought it was scam ooo. I wouldn't mind if it goes for over 5k, its worth it. Thank you!"

    Theressa, Igbinedion University.
  • "I did not see my project topic on your website so I decided to call your customer care number, the attention I got was epic! I got help from the beginning to the end of my project in just 3 days, they even taught me how to defend my project and I got a 'B' at the end. Thank you so much researchwap.com, infact, I owe my graduating well today to you guys...."

    Joseph, Abia state Polytechnic.
  • "My friend told me about ResearchWap website, I doubted her until I saw her receive her full project in less than 15 miniutes, I tried mine too and got it same, right now, am telling everyone in my school about researchwap.com, no one has to suffer any more writing their project. Thank you for making life easy for me and my fellow students... Keep up the good work"

    Christiana, Landmark University .
  • "I wish I knew you guys when I wrote my first degree project, it took so much time and effort then. Now, with just a click of a button, I got my complete project in less than 15 minutes. You guys are too amazing!."

    Musa, Federal University of Technology Minna
  • "I was scared at first when I saw your website but I decided to risk my last 3k and surprisingly I got my complete project in my email box instantly. This is so nice!!!."

    Ali Obafemi, Ibrahim Badamasi Babangida University, Niger State.
  • To contribute to our success story, send us a feedback or please kindly call 2348037664978.
    Then your comment and contact will be published here also with your consent.

    Thank you for choosing researchwap.com.