Strength Prediction Model for Concrete Made with Different Grades of Nigerian Portland Limestone Cement
Authors: Fapohunda CA, Adigo BC
An easy, rapid, cheap, and reliable means of predicting the 28-day compressive strength of structural concrete, at very early state and at very affordable cost, will be helpful in quality control measures of structural concrete produced in remote sites. This paper presents the results of a compressive strength model developed to predict the 28-day compressive strength within hours of casting. The model was developed on the basis that the strength of concrete is fundamentally a function of the volume of voids in it, together with the governing equation expressing this concept and that the concrete is a multi-phase system consisting of cement, fine aggregate, coarse aggregate, evaporable water and non-evaporable water. The equation arising from this model uses the properties of concrete ingredients and the wet density of freshly mixed concrete that can be easily measured on site in a small-scale laboratory. The variables of the equation were then inputted into appropriate spreadsheet to give the value of the 28-day compressive strength once the variables are imputed. The results of 28-day compressive strength obtained from the equation obtained from the model compared well with the results obtained from the laboratory. Also, for its simplicity, implementation of the model by Nigerian Constructors and Engineers will make quick strength determination at early stage easy, to forestall lower strength development in concrete, and the attendant failures.
Affiliations: Department of Civil Engineering, Federal University, Oye-Ekiti, Nigeria.
Keywords: Air Voids, Compressive Strength, Porosity, Strength Relations, Strength-prediction
Published date: 2020/06/30