A Comparative Analysis of the Rebound Hammer and Pullout as Non-Destructive Method in Testing Concrete

Festus Chukwudi Onyeka

doi:10.24018/ejers.2020.5.5.1903

Abstract

A comparative analysis between Rebound Hammer and Pullout method in testing concrete was conducted in this study. Experimental analysis were carried out to compare the correctness between the two testing method in estimating the strength of concrete. Different cube (cubes of 175 x 175 x 175) samples were prepared using two mix designs of 1:2:4 and 1:3:6 with a constant w/c ratio of 0.45 and were tested at 7, 14, 21 and 28 days. The rebound hammer readings had a correlation coefficient of 0.695 while the pullout had a correlation coefficient of 0.725 for the 1:2:4 mix and the rebound hammer readings for 1:3:6 was 0.724 and that for the pullout was 0.675. From the results obtained, it is observed that the non-destructive testing methods were correlated with the compressive strength results which showed that a higher correlation existed between the Rebound Hammer and the compressive strength than the Pullout. Statistical analysis of the results obtained showed that there was no significant difference between the means of the two methods for both mix at a 0.05 level of significance. However, Rebound hammer method can be recommended as it provides a quicker, less-expensive means of checking the uniformity of concrete even though it shows less sensitivity as concrete matures, unlike the Pullout test in which measuring strength is affected by the arrangement of the embedded insert, the dimensions of bearing ring, the depth of embedment, the concrete age and the type of aggregates uses in concrete.

Highlights

Concrete differs from other construction materials because it can be made from infinite combination of suitable materials and the final properties depend on the treatment it undergoes after arriving at the job site
It is as a result of this environmental degradation that there becomes a need for test methods evaluate and estimate concrete features for quality assurances
The aim of this research is to compare some nondestructive testing methods in order to deduce which of the methods gives more features on the characteristics of concretes

Summary

Introduction

Concrete differs from other construction materials because it can be made from infinite combination of suitable materials and the final properties depend on the treatment it undergoes after arriving at the job site. Though concrete is well known for its high stress resistance and workability, except for some environmental degradation which can limit its performance It is as a result of this environmental degradation that there becomes a need for test methods evaluate and estimate concrete features for quality assurances. Nondestructive test (NDT) is the way of obtaining the information about the state, properties of material without interfering with the attributes of the object or structure [1]. They are those tests that do not alter the concrete and after conducting they do not destroy the concrete

Objectives

Methods

Results