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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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International e-Journal For Technology And Research-2017

Indirect Tensile Strength of Modified Bitumen Mixture Satyanarayana Bale, Head Of Department Of Civil Engineering Ramachandra College of Engineering, Eluru, A.P-534007.India

Abstract: - The performance of flexible pavements depends on bituminous mixture and external factors such as traffic loading and weather conditions. Bitumen mixture is elastic, viscoelastic and plastic material where rate of traffic loading and weather conditions plays very significant role on its behavior .Conventional bitumen mixture is unable bear the present traffic volume and environmental conditions by considering this an attempt has been made to study the indirect tensile strength of modified bitumen mixture using cellulose fiber as a modifier. Higher tensile strength resist the cracks, fatigue and rutting which are common failure in the flexible pavements. For preparation of bituminous concrete mixture (BC) gradation has been taken as per MORTH (table no: 500-18) specification. Bitumen content is optimized at 5% and cellulose binder content has been varied such as 1%, 3% and 5% of total mix. Conducted different types of tests such as penetration, ductility, softening point and indirect tensile strength . It has been observed that the behavior of asphalt cement after adding the modifier differ from percentage to another, At 5% an ideal improvement to the fatigue and rutting resistance properties of the asphalt cement in terms of indirect tensile strength as compared with 1%,2% of modifier and conventional bitumen . The addition of 5% Cellulose is found more significant.

I. INTRODUCTION Bituminous mixture is a composite material consists of bitumen (binder), coarse aggregates, fine aggregates and filler and suitability of these materials according to their availability and specification should be thoroughly examined before undertaking any design methodology.

Different pavement design methods need various types of desirable properties of materials.

Therefore it is very necessary to determine engineering properties of materials that are used in pavement construction. The present study was related to improving the tensile strength of bituminous mixes for resisting the fatigue and rutting potential. Different kinds of basic aggregates tests has been conducted like aggregate impact test, Los Angeles abrasion test, aggregates crushing test, stripping of aggregates and specific gravity . In the same manner basic bituminous tests also conducted such as penetration test, softening point test and ductility test.

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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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International e-Journal For Technology And Research-2017

II. OBJECTIVE OF STUDY The main objective of this research is to study the influence of Cellulose fiber (C) on fatigue resistance of asphalt mixtures, and to compare them with the conventional bitumen mixture in order to understand fatigue mechanism with the aim of preventing fatigue cracking in asphalt pavement. Therefore to achieve the main aim of the study, the following tasks were performed. a) b) c)

d)

To study the basic properties of aggregates. To study the basic properties of conventional bitumen To study the basic properties of modified bitumen using cellulose fiber with varying the fiber content i.e. 1%, 3 % and 5% and comparing the results with conventional bitumen mixture in terms of increasing pavement fatigue life.  To study the tensile strength of conventional bitumen and modified bitumen with varying fiber content i.e. 1 %, 3 % and 5% by using indirect tensile strength method and comparing the results in terms of increasing the pavement fatigue life 

III. EXPERIMENTAL INVESTIGATIONS This chapter describes the experimental works carried out on the materials, bitumen and bituminous mixes.

Aggregates For preparation of bituminous concrete mixes (BC) grade-1 the sizes of combined aggregates are chosen according to MORTH guidelines. Quantity of varies sizes of aggregates and physical properties of aggregates are given in Table 1 and Table 2 respectively. A particular type of binder and fiber in required quantities were mixes as per Marshall Procedure (preparation of specimen for IDT test is same as Marshall Specimen).



Table 1:- Quantity of aggregates for BC (MORTH) Sieve Size 26.5 26.5 19 13.2 9.5 4.75

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% passing 100 19 13.2 9.5 4.75 2.36

Wt. of aggregates 0 1.22 21.11 11.85 23.62 7.92 2|P a g e

14.7 253.3 142.2 283.5 95.0 Copyright@IDL-2017

IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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2.36 1.18 1.18 0.6 0.6 0.3 0.3 0.15 0.15 0.075 Passing of 0.075

10.48 6.00 5.96 4.48 3.42

125.8 72.0 71.5 53.8 41.0 47.3

Table 2:- Physical Properties of aggregates

 S.No 1 2 3 4 5 6 7 8

Test Name Impact Value (%) Los Angeles abrasion value (%) Crushing Test (%) Stripping of bitumen aggregates (%) Specific gravity Flakiness index (%) Elongation index (%) Water absorption (%)

Standard IS:2386 (P-IV) IS:2386 (P-IV)

Results 21 25

Accepted Limit 30 % Max 30 % Max

IS:2386 (P-IV) IS:6241

23 97

30 % Max 95 % Min

IS:2386 (P-III) IS:2386 (P-I) IS:2386 (P-I) IS:2386 (P-III)

2.65 20 23 0.1

2.5-3.2 30 % Max 30 % Max 2 % Max

Binder and Modifier For this study 60/70 grade of bitumen as a binder and cellulose fiber as a modifier are used to prepare mix. Properties of bitumen and modified bitumen are given below.

Table 3:- Results of Penetration Test Test Name Penetration at 250C (mm)

Fiber Name 0% Cellulose fiber (C) 63

1% 46

3% 40

5% Standard 32 IS:1203

Table 4:- Results of Softening Point Test Test Name Softening point 0C

Fiber Name 0% Cellulose fiber (C) 49

1% 52

3% 57

5% Standard 61 IS:1205

Table 5:- Results of Ductility Test IDL - International Digital Library

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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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Test Name Ductility (cm)

Fiber Name 0% Cellulose fiber (C) 80

1% 26

3% 20

5% Standard 12 IS:1208

Indirect Tensile Strength Test (IDT) This experiment has been conducted according to standards of ASTM D6931-07. The IDT strength of bituminous mixtures is performed by loading a cylindrical specimen across its vertical diametral plane at a specified rate of deformation and test temperature. The peak load at failure is recorded and used to calculate the IDT strength of the specimen.IDT strength values are helpful to estimated the resistance against fatigue and rutting. IDT strength results for varies concentration of fiber and increased IDT strength due addition of fiber are shown in table 5 and table 6 respectively. The following equation is used for calculating the indirect tensile strength of specimen.

2000 x P ST = Î xDxT Where ST == Indirect Tensile Strength, KPa P = Maximum Load, N t = Specimen height before testing, mm D = Specimen Diameter, mm Table 6:- Results of IDT Strength Test

S.No % of Cellulose fiber 1 2 3 4 1.4 1.2 1 I 0.8 D 0.6 T 0.4 0.2 IDL - International Digital Library 0 0%

IDT strength (N/MM2) 0.92 1.03 1.17 1.40

0% 1% 2% 3%

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1%

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3%

% of Cellulose fiber

5%

IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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International e-Journal For Technology And Research-2017

Fig 1: IDT 0% of fiber

strength v/s S.No 1 2 3

% of Cellulose fiber 1% 3% 5%

% of increased IDT strength 13% 27% 52%

Table 7:- Increased IDT strength due to addition of fiber IV. CONCLUSIONS Based on the results and experimental investigations the following conclusions have come.

Basic bituminous tests i.e. softening point, penetration and ductility have been increasing with increased percentage of cellulose fiber which is desired requirement to resist the fatigue and rutting.

Indirect tensile strength which is represents potential capacity of resisting the fatigue, cracks and rutting also increasing with the increased percentage of cellulose fiber. From the above results 5% of cellulose fiber shows more significant this reduces fatigue and rutting up to 52% subsequently it increases the flexible pavements serviceability and life time.

V. SCOPE Different types of fibers like alumina magnesium silicate, glass fiber, asbestos polyester, polypropylene, paper sludge and crumb rubber can also be added as a bitumen modifier in place of cellulose fiber. Add more than 5% of cellulose fiber and study the above properties.

VI. REFERENCES [1] Standard Test Method for Indirect Tensile (IDT) Strength of Bituminous Mixtures as per ASTM D6931-07 [2] Farag Khodary Moalla Hamed (2014), Evaluation of Fatigue Resistance for Modified Asphalt Concrete Mixtures Based on Dissipated Energy Concept.

[3] Indirect tensile strength characteristics school of engineering, Cochin University of science and technology.

[4] MORTH Recommendations.

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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017

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International e-Journal For Technology And Research-2017

[5] Debashish Kara (2012), A Laboratory Study of Bituminous Mixes Using A Natural Fibre [6] AASHTO designation. (2000). lab book, “to perform penetration test on given bitumen sample”, pp.49.

[7] Ali Akbar yousefi, (2009). “polymer-modified bitumen from the wastes of petrochemical plants”, Iranian polymer journal, volume 18 number 3, pp. 209.

[8] American association of state highway and transportation officials (AASHTO). April (2000) [9]“ AASHTO provisional standards”, edition.american association of state highway and transportation officials. Washington, d.c.

[10] ASTM (1998). ASTM d5-97, (1998). “Standard test method for penetration of bituminous materials”, annual book of ASTM standards, volume 04.03, American society for testing and materials, Philadelphia 19103-1187.

[11] Bradley j. putman, (2011). “Effects of fiber finish on the performance of asphalt binders and mastics”, volume 2011, article id- 172634, pp.11.

[12] Brown, e.r., kandhal, p.s., lee, d.y. and lee, k.w. (1996). “Significance of tests for highway materials”, journal of materials in civil engineering, vol.8, no.1, pp. 26-40 [13] uraksengoz, ali topal and girayisikyakar, (2009) .“Morphology and image analysis of polymer modified bitumens”, elsevier construction and building materials -23, pp.1987.

[14] C. d. Johnston, (2000). “Fiber-reinforced cements and concretes (Google ebook) “vol.2000. taylor & francis, pp. 372.

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