STUDY OF NON-DISTRUCTIVE TESTS ON DIFFERENT TYPES …€¦ · · 2017-03-30STUDY OF...
Conference Name Seventh Sense Research Group www.internationaljournalssrg.org Page 1 STUDY OF NON-DISTRUCTIVE TESTS ON DIFFERENT TYPES OF MIX PROPORTIONS M.VENKATA PAVAN 1 T.VINOD KUMAR 1 SK.MABU SUBHANI 1 B.RAVALI 1 S.L.P.DURGA DEVI 2 1. UG student, Civil Engineering, KHIT, Guntur, Andhra Pradesh, India. 2. Asst professor, Civil Engineering, KHIT, Guntur, Andhra Pradesh, India. Abstract The need of construction is increasing day to day as the population rate is increasing. Geopolymer concrete is eco-friendly than ordinary concrete. This paper presents the experimental investigation on ordinary and geopolymer concrete using NDT tests like Ultrasonic Pulse Velocity test (UPV) and rebound hammer test. These tests are conducted on the cube specimens of dimensions 150mmX150mmX150mm at different age’s i.e. 7, 14, 28 days. Proportions considered for concrete are cement – fly ash – river sand (100-0-100 %, 60-40- 100%), cement- fly ash – robo sand (100-0-100%, 60- 40-100%). Whereas in geo polymer concrete fly ash- metakaolin is taken in proportions of (100-0%, 60- 40% and 50-50%). Alkaline activators such as sodium hydroxide and sodium silicate with molarity 12M are used in preparing geo-polymer concrete. The main objective of this paper is to obtain the relation between compressive strength and UPV values. Keywords- Flyash, Metakaolin, Robosand, Ultrasonic Pulse Velocity, Rebound hammer. I. INTRODUCTION The non-destructive technique is a method widely using for evaluating the property of materials, component or system without causing any damage to the structure. Any component of structure can be tested a number of times using NDT to ensure the safety, improve output, profitability and continued integrity through the complete lifecycle. In the recent past, there has been an enormous increase in the usage of different types of materials in concrete such as Fly ash. It becomes one of the ingredients of concrete. Measurement of strength of concrete through UPV was initiated in the USA in the mid-1940 s and later adopted everywhere as NDT on concrete. Ultrasonic Pulse Velocity (UPV) is one of the non-destructive methods used for testing of the quality of concrete, homogeneity and compressive strength by the regression equation. UPV methods basically consist of transmitting the mechanically generated pulses (in the frequency ranges of 20-150/s) through concrete with the help of electro-acoustic transducers for measuring the velocity of the longitudinal waves generated by the applied pulse. UPV is correlated to much desirable information pertaining to concrete, such as: – Elastic modulus, strength, and uniformity of concrete – Layer thickness, cracking, honeycombing and deterioration of concrete. Rebound hammer is one of the non- destructive testing methods which are used to find out the strength and elastic property of concrete or rock. It is also known as SCHMIDT HAMMER. This equipment was first introduced by ERNST SCHMIDT, a Swiss engineer. This hammer is used to measure the rebound number by using an arbitrary scale ranging from 10-100 of the spring-loaded mass by impacting the hammer at right angles to the concrete or rock surface which should be flat and smooth. II. MATERIALS A. CEMENT Ordinary Portland Cement (OPC) 53 Grade was used in this experimental study. Referring the IS 8112- 1989.The specific gravity of the cement is obtained as 3.10 by using density bottle. Chemical Properties of cement are represented in Table 1. Figure no 1: Cement B. FLY ASH Fly ash is one of the coal combustion product which consists of fine particles collected from boilers with flue gases. Fly ash used in this project is collected
STUDY OF NON-DISTRUCTIVE TESTS ON DIFFERENT TYPES …€¦ · · 2017-03-30STUDY OF NON-DISTRUCTIVE TESTS ON DIFFERENT TYPES OF MIX PROPORTIONS ... like Ultrasonic Pulse Velocity
Seventh Sense Research Group www.internationaljournalssrg.org Page 7
Figure no 13: Relationship between compressive strength and ultrasonic pulse velocity test
There is no specific relation for UPV and compressive strength of concrete. From the above relations of compressive strength and ultrasonic pulse velocity values we have determined the following equations with respect to mix proportions
1. y= 15.21e0.216x (mix 1) (3)
2. y= 0.014e1.411x (mix 2 ) (4)
3. y= 23.79e0.103x ( mix 3) (5)
4. y= 4.249e0.158x (GPC 1) (6)
5. y= 4.193e0.217x (GPC 2) (7)
6. y= 5.105e0.195x ( GPC 3) (8)
Where y= concrete compressive strength
x= velocity value of concrete
Figure no 14: equation obtained for OPC
Figure no 15: equation obtained for GPC
1. For this present experimental investigation we have determined an equation for the comparison of compressive strength and UPV values obtained.
2. The UPV and rebound values increase with the increases of curing period.
3. For mix 2 of OPC concrete the UPV values increases by 3.8% and 6.42% at 7 to 14 days and 14 to 28 days of curing respectively. For the same mix proportion the rebound value increases by 9.1% and 5.5% at 7-14 and 14-28 days of curing respectively.
4. For mix 2 of GPC the UPV values increases with 42.46% and 32.31% at 7-14 days and 14-28 days of curing respectively. For the same mix proportion the rebound increases by 3.57% and 6.89% at 7-14 and 14-28 days of curing respectively.
5. With reduction of fly ash content in GPC the passing time of longitudinal waves is lesser.