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The Effect Of Water/cement Ratio On Compressive Strength Of Palm Kernel Shell Concrete At 1:2:4 Nominal Mix
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2.5 MECHANICAL PROPERTIES OF PALM KERNEL SHELL CONCRETE (PKSC)
The
compressive strength is the most commonly used parameter to describe
the quality of concrete in practice (Weigrink et al, 1996). According to
ASTM C 330-89, the 28-day cylinder compressive strength should not be
less than 17MPa (Neville and Brooks, 2008). Okafor (1988) reported that
the maximum compressive strength of lightweight concrete produced using
this agricultural shell is approximately 25 to 35 MPa. This range is
within the typical compressive strength for structural concrete (20-35
MPa) (Kosmatka et al., 2002). Mannan and Ganapathy (2001) showed that by
using 480kg/m3 cement, a free water to cement ratio of 0.41 and mix
proportion of 1:1.71:0.77 by weight of cement, sand and PKS aggregate,
the 28 day compressive strength of PKS concrete is between 20 and 24 MPa
depending on the curing.
The 28 days cube compressive strength of about 15-25MPa has been reported by them using the batching by volume method.
Ata
et al; (2006) compared the mechanical properties of palm kernel shell
concrete with that of coconut shell concrete and reported the economy of
using PKS as lightweight aggregate. Abang, (1984) found that the use of
higher proportion of PKS lowers both workability and compressive
strength of concrete. Olanipekun et al, (2006) compared concrete made
with PKS and coconut shells. Okafor, (1988) report the strength of PKS
as one of the factors of the strength of palm kernel shell concrete
(PKSC). The flexural behavior of PKS with and without mineral admixture
was reported by Alengaram et al, (2008) and Teo et al; (2006)
respectively. They reported that the performance of PKSC was superior
with respect to ductility. Jummat et al; (2009) also reported the shear
behavior of palm kernel shell foamed concrete and found out that
aggregate interlock behavior of PKS contributes significantly to shear
strength.
2.6 PROPERTIES OF STRUCTURAL LIGHTWEIGHT AGGREGATES
One of the important characteristics of PKSC is the compressive strength. Generally grade 30 concrete is acceptable for structural members, though some of the codes of practice stipulate minimum strength of LWC as 15MPa (FIP Manual, 1983). The highest compressive strength produced by the researchers in the past though fulfills this minimum requirement, higher strength is desirable for the design of structural members. It has been found that the failure of PKS concrete is generally governed by the strength of PKS (Okafor, 1988). However, PKS as LWA can produce poor bond between their surfaces and cement matrix, as they possess smooth and convex surfaces.
The dry density of competed concrete made with different lightweight aggregate varies from about 800-2100 kg/m3 for cube strength ranging from 7 – 50N/mm2 CEB – FIP, (1977).
Structural lightweight concrete is defined in most codes of practice and by RILEM in more restricted way by limiting the density of lightweight concrete of between 1200kg/m3 and 2000 kg/m3.
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ABSRACT - [ Total Page(s): 1 ]ABSTRACT IS COMING SOON ... Continue reading---
APPENDIX A - [ Total Page(s): 2 ] ... Continue reading---
CHAPTER ONE - [ Total Page(s): 3 ]CHAPTER ONE1.0 INTRODUCTION Concrete is a composite engineering material made from the mixtures of cement, water, fine aggregate (sand), coarse aggregates (such as crushed stones or rocks and granite) and a small amount of air in a specific proportion that hardens to a strong bony substance or become ossified. The cement always serves as a binder for the aggregate.The uniqueness quality of concrete makes it desirable as a building material, because it can be moulded into virtually ... Continue reading---
CHAPTER THREE - [ Total Page(s): 3 ]CHAPTER THREE3.0 METHODOLOGYFor better achievement of this project, the following stages are ensured:ï¶ COLLECTION OF MATERIALS The materials comprises of cement, sand, palm kernel shell and water. Palm kernel shell was obtained from a local palm kernel producing village Oko, Irepodun LGA, Kwara State Nigeria.ï¶ PREPARATION OF PALM KERNEL SHELL (PKS)Due to high water absorption of palm kernel shells, it is mandatory to soak the aggregate for about 30 minutes. It i ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 6 ]CHAPTER FOUR4.0 DISCUSSION OF RESULTS4.1 Properties of Palm Kernel Shell {PKS}Results of the study from table 4.1 and figure 4.1 shows that the sieve analysis of PKS and the trend of the percentage cumulative weight retained increases as the sieve sizes decrease. The specific gravity of PKS was found to be 1.37 [Table 4.2] which [Okpala; 1990] classified as light weight aggregate.The water absorption capacity was found to be 10% [Table 4.3]. This value was considered in the design of m ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVE5.0 CONCLUSION AND RECOMMENDATION5.1 CONCLUSIONi. The result of the physical properties obtained show that PKS can be used as partial or complete aggregate substitution for lightweight structural concrete at 1:2:4 nominal mix.ii. The compression strength increases with advancement of age but decreases with increase in water cement ratios. That is, at w/c ratio of 0.3 the compressive strength is 6.5N/mm2 at 28 days while at w/c ratio of 0.5, it is 3.99N/mm2 at ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCENeville, A.M. (1996). “Properties of Concreteâ€. Longman Group Limited, London.Okafor, F.O. (1988). “Palm Kernel Shell as Aggregate for Concreteâ€. Cement Concrete Research Vol. 18, No 6, pp. 901-910.Okpala, D.C. (1990). “Palm Kernel Shell as a Lightweight Aggregate in concreteâ€. Building and Environment 25, pp. 291-296Olanipekun, E.A., Oluola, K.O., and Ata, O. (2006). “A comparative Study of Concrete Properties Using Coconut Shell and Palm Ker ... Continue reading---
