Thesis Abstract

Thesis Overview

<p><br>1.0 INTRODUCTION<br><br>To cure Concrete is to provide concrete with adequate moisture and temperature to foster cement hydration for a period of time. Proper curing of concrete is crucial to obtaining design strength and maximum durability, especially for concrete exposed to extreme environmental conditions at an early age (James et al., 2002). (Teo et al., 2006) defined curing as the process of controlling the rate and extent of moisture loss from concrete during cement hydration. High curing temperature (up to 212ºF or 100ºC) generally accelerates cement hydration and concrete strength gain at early age. Curing temperature below 50ºF (10ºC) are not desirable for early age strength development. When the curing temperature is below 14ºF (-10ºC) the cement hydration process may cease. Concrete needs to be kept for a longer time in formwork when cast in cold weather condition (ACI Committee 308, 2000).<br>On the whole, the strength of concrete, its durability and other physical properties are affected by curing and application of the various types as it relates to the prevailing weather condition in a particular locality, as curing is only one of many requirements for concrete production, it is important to study the curing method of palm kernel shell concrete which best adapts to each individual casting process.<br>The construction industry relies heavily on conventional materials which include cement, crushed rock aggregate and sand or quarry dust for the production of concrete. In the United Kingdom alone, almost 146 million tonnes of sand, gravel and crushed rock aggregates were reportedly mined for construction in 2011 (Department for Communities and Local Government, 2013).<br>In the light of the above, large quantities of cracked palm kernel shells (PKS) are therefore generated by the producers. Palm kernel shells are obtained after extraction of the palm oil, the nuts are broken and the kernels are removed with the shells mostly left as waste. Palm kernel shells are hard stony endocarps that surround the kernel and the shells come in different shapes and sizes (Alangaram et al., 2008). These shells are mainly of two types the “Dura” and “Tenera”. The Tenera is a hybrid which has specially been developed to yield high oil content and it has a thin shell thickness compared to Dura type (Dagwa and Ibhadode, 2008). The use of materials such as rice husk, bagasse, palm kernel shell powder, etc. as fillers and/ or reinforcement agents in polymers and composite materials manufacture such as in brake pads have been reported by several authors (Aigbodion et al., 2010).<br>Natural sand and crushed gravels have been used for many years as aggregates for concrete production due to their availability across the country. However, the high demand for normal weight concrete for construction continues to drastically reduce the natural stone deposits and consequently damage the environment. The introduction of artificial and natural lightweight aggregates (LWA) to replace conventional aggregates for the production of concrete in many developed countries, has brought immense benefits in the development of infrastructure, especially, high rise structures using lightweight concrete (Mahmud et al., 2009).<br>The high cost of building materials in the developing countries of the world can be reduced to a minimum by the use of alternative materials that are cheap, locally available in most countries and which bring about a reduction in the overall dead weight of the building.<br>Some industrial and agricultural bye-products that have little or no economic benefit could gainfully be used as building materials.<br><br>1.1 PROBLEM STATEMENT<br><br>Many problems are associated with concrete with inadequate curing practices.<br>Typically, the most common curing-related distress of concrete is plastic shrinkage cracking.<br>Fresh concrete exposed to hot, windy and arid environment are most easily to show such kind of distress at the surface area. Particularly, when the moisture evaporation rate at the top surface of concrete exceeds the rate at which the moisture is supplied through the concrete bleeding process (the process where excessive mixing water are forced to go upward due to the settlement of aggregate and cement particles), plastic shrinkage cracking<br>is easily formed from the failure to resist the stresses induced by the volumetric contraction of concrete due to moisture loss before enough strength has been developed.<br><br>1.2 AIM OF THE STUDY<br><br>The aim of this research work is to carry out a comparative study on the compressive strength of palm kernel shell concrete using different curing methods<br><br>1.3 OBJECTIVES OF THE STUDY<br>The specific objectives of this research work are:<br><br>To determine the workability of fresh concrete made from palm kernel shell.<br>To determine the physical properties of concrete produce with palm kernel shell using four (4) different curing methods.<br>To carry out statistical analysis on the results of compressive strength of concrete from the four (4) different types of curing methods for 7, 14, 21 and 28 days.<br>1.4 JUSTIFICATION OF THE STUDY<br>This research will help to discover how curing types affect the compressive strengths<br>of palm kernel shell concrete.<br></p>