Statistical Analysis for Concrete Compressive Strength for Dam Complex of Upper Atbara – Setit Project

Abstract

Concrete is considered as the single most widely used material on this era of construction development, therefore, evaluation of its quality is thought to be one of the most important topic that been studied these days. This study aimed towards evaluation of concrete quality in Dam Complex of Upper Atbara - Setit Project in Gdareef State - Sudan using concrete compressive strength as a parameter. More than 4000 concrete compressive strength test sample from different strength classes (C12/15, C20/25, C25/30, C35/45, and C70/85), where two types of Cement Ordinary Portland and Slag cement were used, was taken at DCUAP site, each sample was tested for compressive strength at age of 7 and 28 days according to EN 12390 from the year 2012 to 2016. In this research, statistical analysis for DCUAP concrete compressive strength test was conducted for each class independently to determine compliance with acceptance criteria of (ACI 214.3R-88) and (EN 206-1) codes and then the level of quality control for each concrete class separately was obtained. Then shewhart chart analysis was used to determine whether the process of concrete production was controlled or not. The statistical analysis conducted on this research resulted in conclusion that the degree of quality for the different concrete classes, when the Ordinary Portland Cement was used, varies through the entire period of the project between fair and good with the exception of poor quality level for concrete compressive strength for class C20/25 which was tested at age 28 day. And the degree of quality for the different concrete classes, when the Slag cement was used, varies between fair, good and very good with the exception of excellent quality level for concrete compressive strength for class C12/15 which was tested at age 7day. As when subjected the data for shewhart chart analysis, it shows that the process of concrete production for most of the concrete classes was out of control through the earlier stage of the project, where the Ordinary Portland Cement was used with some exceptions, and went down to be controlled for the rest of the period, where the Slag Cement was used, with some exceptions. At the end it was recommended that, to increase the quality awareness in order to improve it, and also further investigations are required to reveal the deficiencies locations in the process of concrete production at Dam Complex of Upper Atbara to increase the level of quality in the upcoming projects.