Wet Aggregate Impact Value Test | IS Procedure & Calculation
Wet Aggregate Impact Value Test OBJECT To determine the Aggregate Impact value of coarse Aggregate. APPARATUS AIV machine, IS Sieve 12.5mm, 10.0mm, 2.36mm, Oven, Brush, Balance 0.1 gm accuracy. PROCEDURE The test sample shall consist of aggregate the whole of which passes a 12.5-mm IS Sieve and retained on 10 mm IS Sieve. The aggregate comprising the test sample shall be dried in an oven for a period of four hours; the weight becomes constant at a temperature of 105 to 110°C and cooled. The measure shall be filled about one-third full with the aggregate and tamped with 25 strokes of the rounded end of the tamping rod. A further similar quantity of aggregate shall be added and a further tamping of 25 strokes given. The measure shall finally be filled to overflowing, tamped 25 times and the surplus aggregate struck off, using the tamping rod as a straight-edge. The net weight of aggregate in the measure shall be determined to the nearest gram (weight A) and this weight of aggregate shall be used for the duplicate test on the same material. This oven-dried sample is immersed in water for three days. Wet sample after the immersion period is surface dried by suitable cloth. The cup shall be fixed firmly in position on the base of the machine and the whole of the test sample placed in it and compacted by a single tamping of 25 strokes of the tamping rod. The hammer shall be raised until its lower face is 350 mm above the upper surface of the aggregate in the cup, and allowed to fall freely onto the aggregate. The test sample shall be subjected to a total of 15 such blows each being delivered at an interval of not less than one second. The crushed aggregate shall then be removed from the cup and the whole of it sieved on the 2.36 mm IS Sieve and washed with water till no further significant amount passes in one minute. The fraction retained on the sieve shall be dried in an oven to the constant weight at 105 to 110°C and weighed to an accuracy of 0.1 g (weight B). The fraction retained on the sieve (weight B) shall be subtracted from the weight of the original oven dried sample (weight A). The resultant weight (weight A – weight B) shall represent the fraction passing 2.36 mm IS Sieve (weight C). Two tests shall be made. CALCULATION Aggregate Impact Value = (C / A) × 100 Where: C = Weight of fines formed A = Weight of the oven-dried sample
Stripping Value of Aggregate – Complete Guide for Highway Construction
Stripping Value of Aggregate – Procedure, Calculation & Result Interpretation Author: Kishor Kumar · Updated: February 2026 · Read time: ~8 minutes 1. Introduction The Stripping Value Test evaluates the loss of adhesion between bitumen and aggregate in the presence of water. This test is crucial to ensure durable, water-resistant pavements and minimize premature failures. Determines bitumen-aggregate adhesion quality Helps select suitable aggregates for hot mix asphalt (HMA) Predicts susceptibility of pavement to water damage 2. Engineering Significance Stripping of bitumen from aggregates can lead to raveling, potholes, and reduced pavement life. Testing the stripping value identifies weak adhesion and ensures selection of aggregates that will provide long-lasting flexible pavements. 3. Importance of Stripping Value Test Assess aggregate resistance to bitumen stripping under wet conditions Comply with MoRTH and IRC:SP:62 guidelines Ensure durable HMA layers in highways Plan use of anti-stripping agents if necessary Higher stripping values indicate weaker adhesion and potential risk of water damage in pavements. 4. Applications in Highway Construction Selection of coarse aggregates for wearing course layers Checking compatibility of aggregates with bitumen grades Approval of aggregates for DBM and HMA layers Stripping tests are mandatory for NH, SH, PMGSY, and EPC road projects to prevent premature pavement distress. 5. Applicable Standards IS:6241 – Determination of Stripping Value of Aggregates MoRTH Specifications – Hot Mix Asphalt & DBM layers IRC:SP:62 – Guidelines for asphalt mixtures 6. Apparatus Required Aggregate sample sieves and trays Bitumen of specified penetration grade Water bath maintained at 60 ± 1°C Glass containers / beakers Balance and drying oven 7. Test Procedure Heat bitumen to a fluid state and coat aggregate sample thoroughly. Immerse coated aggregate in a water bath at 60°C for 24 hours. Remove aggregates and dry them at 105°C to constant weight. Record initial and final weights to calculate percentage loss of bitumen. 8. Stripping Value Calculation Formula: Stripping Value (%) = ((W1 – W2) / W1) × 100 Initial Weight (W1, g) Final Weight (W2, g) Stripping Value (%) 500 460 8.0 500 450 10.0 Lower stripping values indicate strong adhesion between bitumen and aggregate, ensuring better water resistance. 9. Result Interpretation Stripping Value (%) Aggregate Adhesion Quality < 10% Excellent 10 – 20% Good 20 – 30% Fair > 30% Poor (Not recommended) 10. Field Engineer Notes Ensure uniform bitumen coating for accurate results Maintain water bath temperature precisely at 60°C Use correct aggregate size fraction as per IS:6241 Repeat test for multiple samples and calculate average 11. Common Mistakes Overheating bitumen leading to oxidation Non-uniform coating of aggregates Incorrect water bath temperature Insufficient drying before weighing Always verify equipment calibration and strictly follow IS:6241 guidelines. 12. Stripping Value Excel Sheet ⬇ Download Stripping Value Excel Sheet 13. Who Should Read This Guide? Highway site engineers QA / QC engineers Laboratory technicians Civil engineering students EPC contractors and consultants 14. Conclusion Stripping Value testing is vital for assessing the water resistance of aggregates in bituminous pavements. Accurate testing ensures long-lasting and durable highway surfaces. Frequently Asked Questions What is an acceptable stripping value for aggregates? Less than 10% is excellent; 10–20% is good; above 30% is poor and not recommended. Why is the water bath set at 60°C? This simulates hot climate conditions and accelerates water exposure for evaluating bitumen-aggregate adhesion. Can this test be applied to all aggregate sizes? Only the size fraction specified in IS:6241 should be tested to maintain standardization. Why do stripping results sometimes vary? Variations occur due to bitumen coating method, aggregate type, water bath temperature, and drying accuracy.
Flakiness & Elongation Test
Flakiness & Elongation Index Test – Method Statement Flakiness & Elongation Index Test – IS 2386 Procedure with Calculation Procedure • Apparatus • IS Sieve Table • Results format OBJECT Assess aggregate particle shape quality using the Flakiness & Elongation Index Test as per IS 2386 (Part I). This essential aggregate shape test determines the percentage of flaky and elongated particles that can adversely affect compaction, interlocking, and overall pavement performance. Excessive flaky and elongated aggregates reduce load-bearing capacity, increase voids, and lead to premature failures such as rutting, cracking, and surface deformation in flexible pavements. Therefore, strict compliance with IS specifications is critical for ensuring structural durability and long service life. This practical, site-ready guide covers: Required apparatus and gauge dimensions Step-by-step laboratory procedure Calculation formulas for Flakiness Index (FI) and Elongation Index (EI) Permissible limits as per MoRTH and IS standards Interpretation tips for QA/QC engineers Designed specifically for site engineers, QA/QC teams, and highway professionals, this guide ensures accurate testing, proper documentation, and informed decision-making for high-performance pavement construction. APPARATUS The apparatus for the shape tests consists of the following: A standard thickness gauge A standard length gauge IS sieves of sizes: 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3 mm A balance of capacity 5 kg, readable and accurate up to 1 g The particle shape of aggregates is determined by the percentages of flaky and elongated particles contained in it. For base course and construction of bituminous and cement concrete types, the presence of flaky and elongated particles are considered undesirable as these cause inherent weakness with possibilities of breaking down under heavy loads. Thus, evaluation of shape of the particles, particularly with reference to flakiness and elongation is necessary. The Flakiness Index of aggregates is the percentage by weight of particles whose least dimension (thickness) is less than three-fifths (0.6 times) of their mean dimension. This test is not applicable to sizes smaller than 6.3 mm. The Elongation Index of an aggregate is the percentage by weight of particles whose greatest dimension (length) is greater than nine-fifths (1.8 times) their mean dimension. This test is also not applicable for sizes smaller than 6.3 mm. PROCEDURE Sieve the sample through the IS sieves (as specified in the table). Take a minimum of 200 pieces of each fraction to be tested and weigh them or take the maximum number of pieces available up to 200 Nos. In order to separate the flaky materials, gauge each fraction for thickness on a thickness gauge. The width of the slot used should be of the dimensions specified in column (4) of the table for the appropriate size of the material. Weigh the flaky material passing the gauge to an accuracy of at least 0.1 per cent of the test sample. In order to separate the elongated materials, gauge the non-flaky material for length on a length gauge. The width of the slot used should be of the dimensions specified in column (6) of the table for the appropriate size of the material. Weigh the elongated material retained on the gauge to an accuracy of at least 0.1 per cent of the test sample. … IS SIEVE & GAUGE TABLE Passing through IS Sieve, mm Retained on IS Sieve, mm Weight of fraction (200 pieces), g Thickness gauge size, mm Weight passing thickness gauge (Xi) Length gauge size, mm Weight retained on length gauge (Yi) 63 50 W1 23.90 X1 – – 50 40 W2 27.00 X2 81.00 Y1 40 31.5 W3 19.50 X3 58.00 Y2 31.5 25 W4 16.95 X4 – – 25 20 W5 13.50 X5 40.5 Y3 20 16 W6 10.80 X6 32.4 Y4 16 12.5 W7 8.55 X7 25.5 Y5 12.5 10 W8 6.75 X8 20.2 Y6 10 6.3 W9 4.89 X9 14.7 Y7 Total W = X = Y = OBSERVATIONS and: FORMULAE Record every fraction’s weights clearly. Use at least two significant figures for percentages and record sample piece counts. Flakiness Index = ((X1 + X2 + …) / (W1 + W2 + …)) × 100 Elongation Index = ((Y1 + Y2 + …) / (W1 + W2 + …)) × 100 Fraction Total pieces taken (Wi) Flaky weight (Xi) Elongated weight (Yi) Remarks 63–50 mm 50–40 mm 40–31.5 mm 31.5–25 mm 25–20 mm 20–16 mm 16–12.5 mm 12.5–10 mm 10–6.3 mm Total RESULT I. Flakiness Index = X II. Elongation Index = Y NOTES & REFERENCES This document preserves the original technical content. Do not alter the definitions if your contract specification references a specific IS edition. Reference: IS 2386 Part 1 – Methods of Test for Aggregates for Concrete (Particle Shape Tests). Record environmental conditions and the balance calibration status with every test batch for traceability. Permissible Limits as per MoRTH Application Combined FI + EI Limit Bituminous Concrete (BC) ≤ 30% Dense Bituminous Macadam (DBM) ≤ 35% Wet Mix Macadam (WMM) ≤ 35% Note: Always verify latest MoRTH revision applicable to your contract. Document: • Generated: 20 Nov 2025 Enter Values to Calculate Indices W Values X Values Y Values Calculate Results: Flakiness Index: 0% Elongation Index: 0% Quick Reference: Flakiness & Elongation Index Test Applicable Aggregate Size: Only aggregates ≥6.3 mm are tested. Minimum Sample Count: 200 pieces per sieve fraction (or maximum available). Flakiness Index Criterion: Particles with thickness < 0.6 × mean size. Elongation Index Criterion: Particles with length > 1.8 × mean size. Required Gauges: Thickness gauge for flakiness; Length gauge for elongation. Accuracy: Weigh materials to at least 0.1% accuracy of sample weight. Outcome: FI = (Flaky Weight / Total Weight) × 100; EI = (Elongated Weight / Total Weight) × 100. Purpose: Ensures aggregates are suitable for pavement and concrete strength requirements. Top FAQs – Flakiness & Elongation Index Test What is the minimum aggregate size for these tests? Aggregates smaller than 6.3 mm are not tested. Why are flaky and elongated particles undesirable? They reduce pavement strength and break easily under heavy loads. How many aggregate pieces must be tested?
Water Absorption Test
Water Absorption Test of Coarse Aggregate — Objective, Procedure & Calculation Water Absorption Test of Coarse Aggregate The Water Absorption Test determines the percentage of water absorbed by coarse aggregates, providing an indication of pore structure, density, and suitability for high-quality concrete and asphalt works. Objective To determine the Water Absorption (%) of a coarse aggregate sample using SSD and Oven-dry mass values. Apparatus Required Tray or suitable container Balance (Capacity ≥ 3 kg, Accuracy 0.5 g) Oven (100–110°C) Cotton cloth Test Procedure 1. Immersion (Saturation) Take at least 2000 g (2 kg) of aggregate. Immerse in clean water for 24 hours to fill internal pores. 2. Saturated Surface Dry (SSD) Condition Remove the sample and wipe gently with a cotton cloth. Ensure no visible free water film remains on the surface. Weigh the sample → SSD Mass (A). 3. Oven Drying Place SSD sample in oven at 100–110°C for 24 hours. Cool it and weigh → Oven‑Dry Mass (B). 4. Repeat Trial Repeat the procedure on another sample and take the average. Calculation Water Absorption (%) = (A − B) / B × 100 Where: A = SSD Mass of aggregate B = Oven‑Dry Mass of aggregate Example If: A (SSD Mass) = 2045 g B (Oven-Dry Mass) = 2000 g Water Absorption (%) = (2045 − 2000) / 2000 × 100 = 45 / 2000 × 100 = 2.25% Importance in Construction Mix Design Adjustments: Highly absorptive aggregates steal mix water → affects workability. Durability: Higher absorption = higher porosity → weaker freeze-thaw and weathering resistance. ✔️ Typical Acceptable Limits Aggregate Type Max Water Absorption (%) Coarse Aggregate (Normal concrete) ≤ 2% Fine Aggregate (Sand) ≤ 3% For high-performance or severe exposure concrete, stricter limits may apply. Background & Standard Reference The Water Absorption Test is covered under IS 2386 (Part 3) – Specific Gravity, Density, Voids, Absorption and Bulking. This test provides insight into the internal pore structure of aggregates, which directly affects concrete durability, water demand, and long‑term performance. Aggregates with excessive pores tend to absorb more water, which may lead to reduced compressive strength and increased shrinkage. By determining absorption, engineers calibrate mix water content accurately to achieve the target workability and strength parameters. Factors Affecting Water Absorption Aggregate Type: Crushed rock typically has lower absorption than natural aggregates. Surface Texture: Rough, angular particles may retain more surface moisture. Pore Structure: Aggregates with interconnected pores have higher absorption levels. Weathering: Older, weathered aggregates tend to be more porous. Mineral Composition: Some minerals inherently exhibit higher porosity. Significance of SSD Condition The SSD (Saturated Surface Dry) condition is critical because it represents the state where internal pores are full of water while the exterior surface is dry. This allows mix water calculations to remain accurate. If aggregates are not brought to SSD before batching, they either absorb mix water (leading to lower workability) or contribute excess water (making the mix too wet). The SSD condition ensures correct water‑cement ratio, the single most important factor governing concrete strength. Impact on Concrete Performance Water absorption is directly linked to aggregate quality. Aggregates with low absorption are denser and more durable, making them suitable for high‑strength and long‑life structures. On the other hand, aggregates with high absorption may lead to increased permeability, reduced freeze‑thaw resistance, and potential durability issues. Additionally, when absorption is high, the concrete mix becomes unpredictable without proper adjustments, affecting slump, cohesiveness, and compaction. Precautions Ensure aggregates are completely submerged during the 24‑hour soaking period. Wipe surface moisture gently—over‑drying may lead to inaccurate SSD readings. Do not exceed oven temperature beyond 110°C to avoid thermal damage. Use a calibrated balance for precise mass measurements. Allow oven‑dry samples to cool in a desiccator if available, to prevent moisture uptake from air. Notes for Field Engineers In site conditions, aggregates stored in open yards exhibit varying levels of moisture. Regular absorption testing helps determine free moisture correction during batching to maintain consistent mix quality. For automated batching plants, entering accurate absorption values ensures the batching software adjusts water content correctly. This prevents issues such as plastic shrinkage, excessive bleeding, or segregation in fresh concrete. IS Code References IS Code Description IS 2386 (Part 3) Methods of Test for Aggregates – Specific Gravity, Density, Voids & Water Absorption IS 383 Specification for Coarse and Fine Aggregates for Concrete IS 456 General concrete requirements & material quality guidance Frequently Asked Questions (FAQ) 1. What is a good water absorption value for coarse aggregates? For most concrete works, water absorption should be ≤ 2%. Lower values indicate denser and more durable aggregates. 2. Why is SSD condition important? SSD ensures that aggregate pores are filled without free surface water. This prevents errors in mix design water calculations. 3. Can high water absorption affect concrete strength? Yes. Aggregates with high absorption draw water from the concrete mix, reducing effective W/C ratio and causing poor workability and potential strength loss. 4. How often should this test be performed? Typically during material approval and periodically during construction to ensure consistent aggregate quality. 5. Do different rocks have different absorption characteristics? Yes. Dense rocks like basalt and granite have low absorption. Porous rocks like sandstone and lightweight aggregates have higher absorption. Related Aggregate Tests for Highway & Concrete Works Explore detailed test procedures, calculations and acceptance criteria as per IS, MoRTH & IRC specifications: ✅ Aggregate Impact Value (AIV) Test – Toughness of Aggregates ✅ Los Angeles Abrasion Test – Wear & Abrasion Resistance ✅ Aggregate Crushing Value (ACV) Test – Strength Evaluation ✅ Flakiness & Elongation Index Test – Shape Characteristics ✅ Water Absorption Test – Durability & Porosity Check Pro Tip: Use AIV, ACV, Los Angeles Abrasion, and Shape & Water Absorption Tests together to ensure aggregate suitability for bituminous layers & cement concrete as per MoRTH Section 400 & 500.
Aggregate Crushing Value Test
Aggregate Crushing Value Test — Procedure, Calculation & Limits | QC for Pavements Aggregate Crushing Value (ACV) Test — Procedure, Calculation & Acceptance Limits Quick lab method for QC of aggregates used in concrete pavements — Field & Lab Overview The Aggregate Crushing Value (ACV) test measures the resistance of an aggregate sample to crushing under a gradually applied compressive load. The result helps determine suitability of aggregates for different pavement layers and wearing surfaces. Why This Test Matters in Highway Construction In highway and pavement engineering, aggregates form the backbone of structural layers such as Sub-Base, Base, and Surface Courses. Their strength directly influences the ability of pavements to resist traffic loads, impacts, and repeated loading without excessive crushing or breakdown. The Aggregate Crushing Value (ACV) test provides a relative measure of the resistance of aggregates to crushing under gradually applied compressive loads, as defined by IS 2386 (Part IV). Aggregates with a low ACV (i.e., lower percentage of fines) indicate higher strength and durability, which is critical for long-lasting road surfaces and reduced maintenance costs. As per standard practice, the ACV of aggregates used in wearing surfaces (e.g., concrete pavements) should be controlled rigorously to ensure structural performance over the design life. Aggregates failing this test may lead to premature rutting, surface degradation, and loss of serviceability. Apparatus Item Specification / Notes Steel cylindrical measure Internal diameter 115 mm, height 180 mm Plunger / piston Diameter 150 mm (for main apparatus) Tamping rod Diameter 16 mm (rounded end), length 450–600 mm Balance Capacity ≈ 3 kg with 0.01 g accuracy Compressive testing machine 40 tonnes capacity, uniform loading rate 4 tonnes/min IS sieves 12.5 mm, 10 mm, and 2.36 mm Sample Selection & Preparation Use aggregate passing 12.5 mm and retained on 10 mm IS sieve. Ensure the aggregates are surface-dry (no visible free moisture). Sample weight: as required by the cylinder capacity — record dry weight (W1). Procedure (Step-by-step) The aggregate passing 12.5 mm IS sieve and retained on 10 mm IS sieve shall be selected for standard test. The aggregate should be in surface dry condition before testing. The cylindrical measure shall be filled by the test sample of aggregate in three layers of approximately equal depth, each layer being tamped 25 times by the rounded end of the tamping rod. After the third layer is tamped, using the tamping rod as a straight edge levels off the aggregate at the top of the cylindrical measure. Weigh the sample and repeat the test for another trial. The cylinder of the test apparatus shall be placed in position on the base plate; place one third of the test sample in this cylinder and tamp 25 times by the tamping rod. Similarly, the other two parts of the test specimen are added, each layer being subjected to 25 blows. The surface of the aggregates shall be levelled and insert the plunger so that it rests on this surface in level position. Keep the cylinder with the test sample and the plunger in position and place on the compression testing machine. Load is then applied through the plunger at a uniform rate of 4 tons per minute until the total load is 40 tonnes, and then release the total load. Remove the aggregates including the crushed portion from the cylinder and sieve on a 2.36 mm IS sieve. Collect the material, which passes this sieve. The above crushing test shall be repeated on second sample of the same weight in accordance with above test procedure. Thus two tests are made for the same specimen for taking an average value. Calculation Aggregate Crushing Value (ACV) is the percentage ratio of crushed fines to the total sample weight. Aggregate Crushing Value = (W2 / W1) × 100 Where: W1 = Total dry weight of sample W2 = Weight of material passing 2.36 mm IS sieve Report: Mean of two test results Results & Reporting Report the mean of the two test values as the final ACV for the aggregate sample. Include: Sample identification and date Apparatus used and calibration status W1 and W2 values for both trials and the mean ACV Any deviations from standard procedure Acceptance Limits Application Maximum ACV (%) Cement concrete pavements 30 Wearing surfaces 45 Frequently Asked Questions Why do we use a 2.36 mm sieve for fines? 2.36 mm is the standard IS limit for defining crushed fines in this test — it provides a consistent basis to compare strength characteristics across aggregate sources. What if my aggregate grading differs? If grading is outside the specified range (12.5–10 mm) use a representative fraction or follow the standard practice for coarse/fine fractions as specified in the relevant code. Notes & Best Practices Always run two trials and report the mean to reduce random error. Ensure the compression machine platen and the plunger are clean and parallel before applying load. Record ambient conditions and any visible degradation of sample during handling. Quick Checklist Aggregate: 12.5–10 mm Tamping: 25 blows/layer Loading: 4 t/min to 40 t Sieve for fines: 2.36 mm Acceptable ACV: <=30% (concrete pavements) Useful snippets <strong>ACV = (W2 / W1) × 100</strong> Use this procedure Related Aggregate Tests for Highway & Concrete Works Explore detailed test procedures, calculations and acceptance criteria as per IS, MoRTH & IRC specifications: ✅ Aggregate Impact Value (AIV) Test – Toughness of Aggregates ✅ Los Angeles Abrasion Test – Wear & Abrasion Resistance ✅ Aggregate Crushing Value (ACV) Test – Strength Evaluation ✅ Flakiness & Elongation Index Test – Shape Characteristics ✅ Water Absorption Test – Durability & Porosity Check 📌 Pro Tip: Use AIV, ACV, Los Angeles Abrasion, and Shape & Water Absorption Tests together to ensure aggregate suitability for bituminous layers & cement concrete as per MoRTH Section 400 & 500.
Los Angeles Abrasion Test IS 2386 Part IV
Los Angeles Abrasion Test – Procedure, Calculation, Apparatus & Limits (IS 2386 Part IV) The Los Angeles Abrasion Test is one of the most important tests used to evaluate the toughness and abrasion resistance of coarse aggregates used in road construction and concrete works. This test determines how aggregates behave when subjected to wear, impact and grinding action. Aggregates with high abrasion resistance ensure longer pavement life, better durability and reduced maintenance costs. The test is conducted according to IS 2386 (Part IV) – Methods of Test for Aggregates and is also specified in MoRTH Specifications for Road and Bridge Works (5th Revision, 2013). Importance of Los Angeles Abrasion Test in Highway Engineering Aggregates are the primary load-bearing material in flexible pavements. When traffic loads move over pavement surfaces, aggregates are continuously subjected to: Abrasion due to tyre friction Impact from moving vehicles Grinding action between aggregate particles If aggregates are weak, they will break into smaller particles, causing: Pavement rutting Loss of surface texture Premature road failure The Los Angeles Abrasion Test helps engineers select durable aggregates suitable for highway construction. Objective of the Test The main objectives of the Los Angeles Abrasion Test are: To determine the abrasion resistance of aggregates To measure the toughness of aggregates To evaluate the quality of aggregates for road works To ensure aggregates meet MoRTH specifications Relevant Standards IS 2386 (Part IV) – 1963 Methods of test for aggregates for concrete. MoRTH Specifications (2013) Specifications for road and bridge works. ASTM C131 / ASTM C535 International standards for abrasion testing. Apparatus Required for Los Angeles Abrasion Test Los Angeles Abrasion Machine Hollow steel drum Internal diameter: 700 mm Length: 500 mm Rotational speed: 30–33 rpm Steel Abrasive Balls Diameter: 48 ± 2 mm Weight: 390 – 445 g each Hardness: 400 – 450 HB IS Standard Sieves Weighing Balance (accuracy 1 g) Drying Oven (105 – 110°C) Tray and sieve brush Sample Preparation Proper sample preparation is essential for accurate test results. The following steps should be followed: Collect representative aggregate samples. Wash aggregates to remove dust and impurities. Dry the aggregates in an oven at 105–110°C. Allow the sample to cool to room temperature. Weigh the required sample weight (usually 5000 g). Grading of Aggregates for the Test Grading Aggregate Size (mm) Sample Weight (g) No. of Revolutions Typical Use A 63 – 50 5000 500 Granular Sub Base B 50 – 40 5000 500 WMM Base C 40 – 25 5000 500 Dense Bituminous Macadam D 25 – 20 5000 500 Bituminous Macadam E 20 – 12.5 5000 1000 Bituminous Concrete Test Procedure PROCEDURE – LOS ANGELES ABRASION TEST Clean aggregates dried in an oven at 105–110°C shall be used for testing. The grading used in the test should be nearest to the grading to be used in the construction. Aggregates weighing 5 kg for grading A, B, C or D and 10 kg for grading E, F or G may be taken as test specimen and placed in the cylinder. Choose the abrasion charge depending on the grading of the aggregate and place in the cylinder of the machine. Fix the cover dust tight and rotate the machine at a speed of 30 to 33 revolutions per minute. The machine shall be rotated for 500 revolutions for grading A, B, C and D, and for grading E, F and G it shall be rotated for 1000 revolutions. After the desired number of revolutions, stop the machine and discharge the material from the machine taking care to take out entire stone dust. Using a sieve of size 1.70 mm IS Sieve, the material is first separated into two parts and the finer portion is taken out and sieved further on a 1.70 mm IS Sieve. The portion of material coarser than 1.70 mm size is washed and dried in an oven at 105–110°C to constant weight and weighed correct to one gram. Calculation of Los Angeles Abrasion Value The Los Angeles abrasion value is calculated using the following formula: Los Angeles Abrasion Value (%) = ((A − B) / A) × 100 Where: A = Original weight of sample (g) B = Weight retained on 1.70 mm sieve after test (g) Example Calculation Initial weight of sample = 5000 g Weight retained after test = 3600 g Abrasion Value = ((5000 − 3600) / 5000) × 100 Abrasion Value = 28% Permissible Limits as per MoRTH Layer Maximum LA Abrasion Value Granular Sub Base 45% Base Course 40% Bituminous Layers 35% Wearing Course 30% Advantages of the Test Simple and widely used method Provides reliable measure of aggregate toughness Essential for pavement design Helps maintain highway quality control Limitations of the Test Does not fully simulate field traffic conditions Results may vary for soft aggregates Not suitable for very small aggregates Frequently Asked Questions (FAQ) What is the Los Angeles Abrasion Test? It is a laboratory test used to determine the resistance of aggregates to abrasion and impact. What is the maximum permissible abrasion value? For wearing courses in highways, the maximum value is typically 30%. Which IS code specifies the test? The test is specified in IS 2386 (Part IV). What does a lower abrasion value indicate? Lower abrasion value means stronger and more durable aggregates. Related Aggregate Tests for Highway & Concrete Works Explore detailed test procedures, calculations and acceptance criteria as per IS, MoRTH & IRC specifications: ✅ Aggregate Impact Value (AIV) Test – Toughness of Aggregates ✅ Los Angeles Abrasion Test – Wear & Abrasion Resistance ✅ Aggregate Crushing Value (ACV) Test – Strength Evaluation ✅ Flakiness & Elongation Index Test – Shape Characteristics ✅ Water Absorption Test – Durability & Porosity Check 📌 Pro Tip: Use AIV, ACV, Los Angeles Abrasion, and Shape & Water Absorption Tests together to ensure aggregate suitability for bituminous layers & cement concrete as per MoRTH Section 400 & 500.
Aggregate Impact Value Test | Procedure, Formula & IS Code
The Aggregate Impact Value (AIV) Test evaluates the toughness of coarse aggregates by measuring their resistance to impact or sudden shocks, ensuring their suitability for road and highway construction.