Effect of age on nondestructive tests results for existing concrete

Dissertant

Radi, Mushtaq Sadiq

Thesis advisor

Juni, Hasan Hammudi
al-Mashhadani, Shakir A.

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

The aim of this study is to investigate the influence of age on the measurement of the nondestructive tests of different types of concrete.

This study involves two types of the Investigational work.

The first type deals with field investigation on existing concrete, to evaluate the effect of age on measurements of two types of nondestructive test method, rebound hammer and ultrasonic pulse velocity tests.

An existing reinforced concrete structure of multistory buildings under construction is considered for this part.

Repetitive nondestructive measurements were taken from the same location in different ages, the age of concrete under test was ranging from 90 to 365 days.

Measurements results of the field nondestructive testes exhibit slight increasing with age.

It is found that the percentage increase of rebound hammer and ultrasonic pulse velocity for existing concrete at long-term age (the last measurements) are ranged between (12.5 -18) % and (1.62-3.95) % respectively expressed as a percentage of the first test corresponding measurements.

The second type involves laboratory investigation.

Specimens from concrete mixes with a 28 days compressive strength ranging from 25-55 MPa was prepared and tested with nondestructive (core compressive strength, rebound number, and ultrasonic pulse velocity) and destructive (cube compressive strength, splitting tensile strength, and modulus of rupture) tests were investigated for all mixes at 7, 28, 60, 90, 120,180, 270 and 365 days.

Results demonstrate that in general, all tests results (nondestructive and destructive tests) exhibit continuous increase with increase of curing age, the increase rate is decrease with age.

The rebound number and ultrasonic pulse velocity show a faster rate of increase compared with the destructive tests.

The percentage increase of compressive strength, splitting tensile strength, modulus of rupture and core compressive strength for all concrete mixes at long-term age are ranged between (26-68)% , (20-32)%, (17-22)%, and (26-51) % respectively expressed as a percentage of the 28 days corresponding values.

Whereas, the long-term increase percentage for rebound number and ultrasonic pulse velocity are ranged between (17-24) % and (8.8-13.2) %, respectively as compared with that of 28 days age.

This study also verifies that the water-cement ratio of concrete mix is a major factor that affects the rate of development of destructive and nondestructive tests.

Finally, empirical formulas are suggested to estimate the compressive strength from the above nondestructive tests.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Concrete

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-419614