eng
Science and Education Publishing
International Journal of Materials Lifetime
2015-06-17
2
1
13
21
10.12691/ijml-2-1-3
IJML2015213
article
An Implicit Response Analysis of Compressive Strength of Concrete Based on Its Ageing Periods and Cement Replacement with Bagasse Ash
C. Nwoye
nwoyennike@gmail.com
1
E. C. Chinwuko
2
P. C. Nwosu
3
N. E. Idenyi
4
Department of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria
Department of Industrial and Production Engineering, Nnamdi Azikiwe University, Awka, Nigeria
Department of Mechanical Engineering, Federal Polytechnic, Nekede, Nigeria
Department of Industrial Physics, Ebonyi State University, Abakiliki, Nigeria
An implicit response analysis of the compressive strength of concrete was carried out based on its ageing periods and extent of cement replacement with bagasse ash. The response coefficient was evaluated to ascertain the viability and reliability of the compressive strength dependence of concrete on the considered input process variables. A two-factorial empirical model was derived, validated and used for the analysis and evaluation. The validity of the model; ζ = - 0.0057ϑ2 – 0.1551ϑ + 0.0002ɤ + 24.153 was rooted on the core model expression ζ - 0.0002ɤ = - 0.0057ϑ2 – 0.1551ϑ + 24.153 where both sides of the expression are correspondingly approximately equal. Regression model was used to generate results of compressive strength of concrete, and its trend of distribution was compared with that from derived model as a mean of verifying its validity relative to experimental results. The results of this verification shows similar shapes and very close alignment of curves translating into a significantly similar trend of data point's distribution for experimental (ExD), derived model (MoD) and regression model-predicted (ReG) results. Evaluations from generated results indicated that the compressive strength per unit input of bagasse ash and ageing period as obtained from experiment, derived model & regression model were 0.3413, 0.3255 & 0.3822 N mm-2 / % and 0.1177, 0.1122 & 0.1318 N mm-2/ days, respectively. Standard errors incurred in predicting the compressive strength of concrete for each value of the bagasse ash input and an ageing period considered as obtained from experiment, derived & regression models were 0.8357, 0.6621, & 2.3973 x 10-5 % and 1.083, 0.6456 & 0.5816 %, respectively. The deviational analysis indicates that the maximum deviation of a model-predicted compressive strength of the concrete from the experimental results is less than 5%. This translated into over 95% operational confidence and response level for the derived model as well as over 0.95 response coefficient of compressive strength (of formed concrete) to the collective operational contributions of the bagasse ash input and ageing periods.
http://pubs.sciepub.com/ijml/2/1/3/ijml-2-1-3.pdf
response analysis
compressive strength
concrete
bagasse ash addition
ageing period