Indian Institute of Technology Bhubaneswar, India Evaluation of Stiffness of Cement Stabilized Granular Lateritic Soils using UPV Test Presented by Dr. Umesh Chandra Sahoo Indian Institute of Technology Bhubaneswar, India 4th International Conference on Transport Infrastructures (ICTI)

OUTLINE OF PRESENTATION Introduction Ultrasonic Pulse Velocity Test Materials and Methods Results and Discussions Conclusions References

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

INTRODUCTION Typical section of flexible pavement Bituminous layer Base Sub-base Subgrade Granular Base Granular Sub-Base

INTRODUCTION Huge length of roads are being constructed in India through various development programmes. Scarcity of good quality natural aggregates in many places has become a hindrance to road construction Transportation of crushed stones from a larger distance causes: Waste of energy Increase in hauling cost Air pollution

Granular Lateritic Soil INTRODUCTION It has prompted to explore the availability of marginal aggregates, locally available granular soils and waste materials and to investigate the feasibility of using these materials in the structural layers of pavements. Usually do not meet the specifications locally available soils marginal aggregates recycled materials Granular Lateritic Soil

Granular Lateritic Soil INTRODUCTION Granular Lateritic Soil Tropical or subtropical residual soil Rich in iron & aluminium oxide

Granular Lateritic Soil INTRODUCTION Granular Lateritic Soil Approximately 3.5% area of India

INTRODUCTION Stabilisation of granular lateritic soil can be employed to make it suitable for subbase and base layer Bitumious layer Base Subbase Subgrade

Flexural modulus for cement bound/ stabilized materials INTRODUCTION Recent Approach of Pavement Analysis Mechanistic Pavement Design Material Properties Elastic Modulus Flexural modulus for cement bound/ stabilized materials

INTRODUCTION Flexural Modulus For an isotropic, homogeneous and elastic material, when the material is flexed i.e., allowed to bend by applying force which is perpendicular to the longitudinal direction of material, the stiffness of the material that resists the bending is known as flexural modulus. Determined by applying cyclic load on a beam sample in a flexure test arrangement This test simulates the stress strain gradient observed in stabilized layers of any pavement However, determination of flexural modulus is a tedious and time consuming

Common Tests used for characterization of stabilized materials: INTRODUCTION Common Tests used for characterization of stabilized materials: Unconfined Compressive Strength Test (UCS) Flexural Strength (FS) Indirect Tensile Strength (ITS)

INTRODUCTION Non-Destructive Tests which may be used for characterization of stabilized material Ultrasonic pulse velocity test (UPV test) Rebound hammer tests Seismic modulus tests Very fast and rapid methods

INTRODUCTION Non-Destructive Tests which may be used for characterization of stabilized material Ultrasonic pulse velocity test (UPV test) Rebound hammer tests Seismic modulus tests Rebound value : A relative measurement of surface hardness

INTRODUCTION Non-Destructive Tests may be used for characterization of stabilized material Ultrasonic pulse velocity test (UPV test) Rebound hammer tests Seismic modulus tests Ultrasonic pulse travels through the mass media; hence, pulse velocity is a relative measurement the elastic properties of the whole mass rather than any surface properties

UPV Test on stabilized materials INTRODUCTION UPV Test on stabilized materials Many researchers have established relationships between pulse velocity and physico- mechanical properties of concrete, but few studies on cement stabilized soils. The relationships developed by Mandal et al (2016) as given below do not address the flexural modulus of the materials, which is desired for mechanistic pavement design. UPV test can also be employed for performance study of constructed stabilized pavements as it is a rapid method of determining the in-situ modulus.

INTRODUCTION Objective of this study: Predicting strength and stiffness of cement stabilized granular lateritic soils using UPV test

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

ULTRASONIC PULSE VELOCITY Ultrasonic waves are stress waves with frequency more than 20 kHz in solid media When a electrodynamic pulse is applied to any material, 3 types of stress waves are generated. P-wave (Longitudal/Primary wave) Body wave Stress waves S-wave (Shear wave) R-wave (Raleigh wave) Surface wave

ULTRASONIC PULSE VELOCITY Due to the transmission of P wave or Primary wave, particles move in the same direction (longitudinal) as the direction of wave propagation. Transverse waves or S waves result in movement of particles in a direction perpendicular to the direction of wave. As the P waves are much faster than S-waves, the arrival of P-wave is recorded first and used for determination of velocity.

ULTRASONIC PULSE VELOCITY TEST t is the transmission time l is the length of transmission of pulse Different Transmission modes in UPV test l UPV test arrangement

ULTRASONIC PULSE VELOCITY TEST The strain range of particles in UPV testings are very small i.e, less than <10-6 Propagation of ultrasonic pulse inside a material depends on the materials properties Important parameters of wave propagation which can be quantified with the material elastic properties in small strain range are velocity and attenuation. However, out of these two parameters, velocity is related to the elastic and mechanical properties.

ULTRASONIC PULSE VELOCITY TEST UPV Test Elastic property: Constrained Modulus Constrained modulus : Stiffness of the material which is a measure of resistance of the particle movement in longitudinal direction due to compression or P wave or longitudinal wave in a mass media either in ultrasonic test or due to seismic wave Vp is ultrasonic pulse velocity in m/s , t is transmission time in sec and l is transmission distance in meter, ρ is density kg/m3, μ is dynamic Poisson's ratio.

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

Detailed Experimental Program MATERIALS AND METHODS Characterization of granular lateritic soil Characterization of cement bound material Strength and Modulus test Ultrasonic Pulse Velocity Test Unconfined Compressive Strength Indirect Tensile Strength Flexural Strength Flexural Modulus Detailed Experimental Program

Characterization of the Granular Lateritic Soil MATERIALS AND METHODS Characterization of the Granular Lateritic Soil Property Lateritic soil Gravel (%) 40.8 Sand(%) 50.1 Silt and clay (%) 9.1 Classification (as per USCS) SW Specific Gravity 2.71 Liquid limit 48.25 plastic limit 31.58 Plasticity index 16.67 Natural moisture content 3% OMC 12.7 MDD (kN/m3) 19.15

MATERIALS AND METHODS Unconfined Compressive Strength (UCS) Indirect Tensile Strength (IDT) Lateritic Soil + Cement % : 2, 3, 4, 6, 8, 10 Uniaxial Compression test Strain rate: 1.25mm/min It is a failure test 60 100 115 115

MATERIALS AND METHODS Flexural Beam Test Monotonic flexure test for determining flexural strength (FS) or modulus of rupture (MOR); Cyclic flexure test for determining the flexural modulus CLS Beam Sample P 75 Monotonic Flexure Test Flexural Strength

MATERIALS AND METHODS Cyclic Flexure Test Loading Frequency= 1Hz time Loading Frequency= 1Hz Stress Ratio = 0.3 Flexural Modulus:

Ultrasonic Pulse Velocity Test on the Samples MATERIALS AND METHODS Ultrasonic Pulse Velocity Test on the Samples Samples were prepared at OMC & MDD and cured for 28 days Transducers used are of 50mm in diameter and maximum resonant frequency of 50 kHz. Three replicate tests were conducted for each specimen in longitudinal direction and the average value was taken.

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

RESULTS AND DISCUSSIONS Relationship Between Ultrasonic Pulse Velocity and Cement Content Pulse velocity varies from 1.18 km/s to 2 km/s for CLS for the cement dosage of 2% to 10%. Strong correlation observed between cement content and pulse velocity. Ultrasonic pulse velocity increases with increase in cement content, almost linearly, which is in line with the previous studies on cemented materials (Barisic et al. 2016).

RESULTS AND DISCUSSIONS Relationship Between Ultrasonic Pulse Velocity and UCS value

RESULTS AND DISCUSSIONS Relationship Between Ultrasonic Pulse Velocity and Flexural Strength

RESULTS AND DISCUSSIONS Relationship Between Ultrasonic Pulse Velocity and IDT

RESULTS AND DISCUSSIONS Relationship Between Ultrasonic Pulse Velocity and Flexural Modulus

RESULTS AND DISCUSSIONS Relationship Between Constrained Modulus and Flexural Modulus

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

CONCLUSIONS Ultrasonic pulse velocity tests can ideally be used to assess the strength and stiffness parameters of the CLS used in subbase and base layers of any pavement. Correlations developed under this study can be suitably used for the cement stabilized lateritic soils within the range of UCS from 2 to 10 MPa.ments. More tests on similar materials need to be conducted for establishing generalized relationships.

Introduction Ultrasonic Pulse Velocity Materials and Methods Results and Discussions Conclusions References

SELECTED REFERENCES Austroads. (2012). Guide to Pavement Technology Part 2: Pavement Structural Design. Austroad, Sydney, Australia. Barisic, I., Dimter, S. and Rukavina, T. (2016). Characterization of Cement Stabilized Pavement layers with ultrasound testing. Technical Gazette, 23 (2), 447‑453. IS 13311-1 (1992). Method of Non-destructive testing of concrete, Part 1: Ultrasonic pulse velocity. Bureau of Indian Standard, New Delhi, India. Mandal, T., Tinjum, J. M., Gokce, A., & Edil, T. B. (2016). Protocol for testing flexural strength, flexural modulus, and fatigue failure of cementitiously stabilized materials using third-point flexural beam tests. Geotechnical Testing Journal, 39(1), 91-105. Rio, L. M., Jimenez, A., Lopez, F., Rosa, F. J., Rufo, M. M. and Paniagua, J. M. (2004). Characterization and hardening of concrete with ultrasonic testing. Ultrasonics, (42), 527–530. Yesiller, N., Hanson, J., Rener, A., and Usmen, M. (2001). Ultrasonic testing for evaluation of stabilized mixtures. Transportation Research Record: Journal of the Transportation Research Board, 1757, 32-42.

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