Marshall Stability Test : -
Introduction : -
This test procedure is used in designing and evaluating bituminous paving mixes. In this Method, the resistance to plastic deformation of cylindrical specimen of bituminous mixture is measured when the same is loaded at the periphery at 5 cm per minute. In this test an attempt is made to obtain optimum binder content for the type of aggregate mix and traffic intensity.

Apparatus : -
Mould Assembly, Sample Extractor, Compaction Pedestal and Hammer, Breaking Head, Loading Machine, Flow meter.
Application of Marshall Stability Test : -

1. The stability values obtained in this test procedure indirectly represent the strength of a paving mix at a zero vertical stress level which is critical.
2. Mixer with very high Marshall stability values and very low Flow values are not desirable as the pavements of such mixes may be brittle and are likely to crack under heavy traffic.

Softening Point Test : -
Introduction : -
The softening point is the temperature at which the substance attains particulars degree of softening under specified condition of test. For bitumen, it is usually determine by Ring and Ball test.

Apparatus : -
Steel Balls, Brass Rings, Support, Bath and stirrer.

Application of softening Point Test : -
Softening point is essentially the temperature at which the bitumen binders have an equal viscosity. The softening Point of tar is therefore related to the equiviscous temperature.

Ductility Test : -
Introduction : -
The ductility is expressed as the distance in centimeters to which a standard briquette of bitumen can be stretched before the thread breaks. The test is conducted at 27 ± 0.5 0 and rate of pull of 50 ± 2.5 mm per minute. The test has been standardized by the ISI.

Apparatus : -
Briquette mould and
Ductility machine

Application of Ductility Test : -

1. A certain minimum ductility is necessary for a bitumen binder. This is because of the temperature changes in the bituminous mixed and the repeated deformations that occur in flexible pavement due to the traffic loads.
2. If the bitumen has low ductility value, the bituminous pavement may crack, especially in cold weather. The ductility values of bitumen vary from 5 to over 100.

Penetration Test : -
Introduction : -
The penetration test determines the consistency of these materials for the purpose of grading them, by measuring the depth to which a standard needle will penetrate vertically under specified condition of standard load, duration and temperature. The softer the bitumen, the greater will be the penetration.

Apparatus : -
Container, Needle, Water-bath, Penetrometer, Transfer tray.

Application of penetration test : -

1. Penetration test the most commonly adopted test an bitumen to grade the material in terms of its hardness.
2. Depending upon the climate condition and type of construction, bitumen of different penetration grades are used, 80/100 bitumen denote that the penetration value range between 80 and 100.
3. For bituminous macadam and penetration macadam Indian Roads Congress suggests bitumen grades, 30/40, 60/70 and 80/0.

Elongation Index : -
Introduction : -
The elongation index of an aggregate is the percentage by weight of particle whose greatest dimension (length) is greater than one and four fifth times (1.8 times) their mean dimension. The test is not applicable to sizes smaller than 6.3 mm.

Apparatus :-
The apparatus consists of a length guage shown in fig , IS sieve of sizes 63, 50, 40, 31.5 , 25, 20, 16, 12.5, 10 and 6.3 mm and a balance to weight the sample.

Application of Shape Tests : -

1. The pavement construction flaky and elongated particles are to be avoided, particularly in surface course. If flaky and elongated aggregate are present in applicable proportions, the strength of the pavement layer would be adversely affected due to possibility of breaking down under loads.
2. In cement concrete the workability is also reduced.
3. However, the reduction in strength in cement concrete depends on the cement content and water-cement ratio.
4. Though elongated shape of the aggregate also affects the compaction and the construction of pavements, there are no specified limit of elongation index values as in the case of flakiness index for different methods of pavement construction.

Flakiness Index : -
Introduction : -
The particle shape of aggregate is determine by the percentage of flaky and elongated particles contained in it. Flakiness index of aggregate is the percentage by weight of weight of particle whose least dimension (thickness) is less than three ?fifths (0.6) of their mean dimension. The test is not applicable to sizes smaller than 6.3 mm.

Apparatus : -
The apparatus consists of a standard thickness guage shown in fig , IS sieve of sizes 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3 mm and a balance to weight the sample.

Aggregate Impact Test : -
Introduction : -
To evaluate the toughness or stone i.e., the resistance of the stones to fracture under repeated impacted may be called an impact test for road stones. Toughness is the property of a material to resist impact. Due to traffic loads, the road stones are subjected to the pounding action or impact and there is possibility of stones breaking into smaller pieces.

Apparatus : -

1. Impact testing machine
2. Measure: - A cylindrical metal measure having internal diameter 7.5 cm and depth 5 cm for measuring aggregate.
3. Tamping rod: - 1 cm in diameter and 23 cm long
4. Sieve: - IS sieve of sizes 12.5 mm, 10mm, and 2.36 mm
5. Balance , Oven

Applications of Aggregate Impact Value : -
The aggregate impact test is considered to be an important test to assess the suitability of aggregate as regards the toughness for use in pavement construction. it is found that for majority of aggregates the aggregate crushing and aggregate impact values are numerically same within in the close limits .but in case of fine grained highly siliceous aggregate which are less resistant to impact than to crushing the aggregate values are higher than the aggregate crushing values.

Los Angeles Abrasion Test : -
Introduction : -
The principal of Los Angeles Abrasion test is to find the percentage wear due to the relative rubbing action between the aggregate and steel balls used as abrasive charge; pounding action of these balls also exist while conducting the test. Los Angeles abrasion test has been standardized by the ASTM, AASHO and also by the ISI

Apparatus : -

1. Los Angeles machine consists of a hollow steel cylinder.
2. Set of steel ball of 48 diameter.
3. Revolution Counter.

Application of Aggregate Crushing Test : -

1. Los Angeles Abrasion test is very widely accepted as a suitable test to assess the hardness of aggregates used in pavement construction.
2. Many agencies have specified the desirable limits of the test, for different methods of pavement constructions.

Aggregate Crushing Value Test : -
Introduction : -
The strength of coarse aggregate is assessed by aggregate crushing test. The aggregate crushing value provides a relative measure of resistance to crushing under a gradually applied compressive load. To achieve a high quality of pavement .aggregate possessing low aggregate crushing value should be preferred.

Apparatus : -

1. Steel cylinder with open ends, and internal diameter 25.2cm.
2. Cylindrical measure having internal diameter of 11.5 cm and height 18cm
3. Steel temping rod.
4. Balance
5. Compression testing machine capable of applying load of 40 tonnes.

Application of Aggregate Crushing Test : -

1. The aggregate crushing value is an indirect measure of crushing strength of the aggregate. Low aggregate crushing value indicates strong aggregate, as the crushed fraction is low.
2. The Aggregate used for the surface course of pavement should be strong enough to withstand the high stresses due to wheel loads, including the steel tyres of loaded bullock-carts.
3. Indian Roads Congress and ISI have specified that the aggregate crushing value of the coarse aggregate used for cement concrete pavement at surface should not exceed 30 percent.