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.

Grain Size Analysis of Soil – Sieve Analysis Procedure, Calculation & Interpretation | HighwayQualityTest Grain Size Analysis of Soil – Sieve Analysis Procedure, Calculation & Interpretation Author: Kishor Kumar · Updated: February 2026 · Read time: ~15 minutes 1. Introduction The Grain Size Analysis of Soil, commonly known as the Sieve Analysis, is a fundamental laboratory test to determine the particle size distribution of soil. Understanding soil gradation is essential for designing pavements, embankments, subgrades, and other civil engineering structures. This test provides critical data for evaluating soil compaction, permeability, and stability. Soil in natural deposits contains a mixture of gravel, sand, silt, and clay. Proper gradation ensures good drainage, uniform compaction, and strong load-bearing characteristics. Coarse-grained soils are better for pavement sub-base, whereas fine-grained soils may need stabilization. 2. Purpose of Grain Size Analysis Determine particle size distribution and gradation Assist in soil classification (Gravel, Sand, Silt, Clay) Design highway subgrades, embankments, and pavement layers Assess permeability and drainage characteristics Guide soil stabilization or replacement decisions 3. Applicable Standards IS 2720 (Part 4) – Grain Size Analysis / Sieve Analysis IS 2720 (Part 1) – Preparation of dry sample MoRTH Specifications – Subgrade, GSB & WMM layer quality ASTM D6913 / D422 – International reference for particle size distribution 4. Apparatus Required Set of standard sieves (4.75 mm to 75 μm) with pan and lid Mechanical or hand shaker Weighing balance (accurate to 0.1 g) Oven for drying soil samples Glass or plastic containers for sample handling Hydrometer (for fine soils & particle 20 mm and organic debris Mix well to homogenize Split sample if needed for multiple tests 6. Test Procedure – Sieve Analysis Step 1: Dry Sieving Stack sieves in decreasing order of aperture size, largest on top, smallest at bottom. Place a pan at the bottom to collect soil passing the smallest sieve. Pour the soil sample on top sieve evenly. Use mechanical shaker or hand shake for 10–15 minutes. Weigh soil retained on each sieve and record the values. Step 2: Wet Sieving (Optional for cohesive soils) Soak sample in water to disintegrate clay lumps. Use dispersion solution (e.g., 0.1 N NaOH) for high plasticity soils. Wash soil over the sieve stack and allow to dry before weighing retained soil. Step 3: Hydrometer Analysis (Fines 4.75 mm Sand: 0.075 – 4.75 mm Silt: 0.002 – 0.075 mm Clay: 0.075 mm and hydrometer for fine particles

Soundness Test of Cement – Le Chatelier Method Author: Kishor Kumar · Updated: February 2026 · Read time: ~8 minutes 1. Introduction The Soundness Test of Cement ensures that cement does not undergo excessive expansion after setting, which can cause cracks in concrete and structural failure. The Le Chatelier Method specifically measures expansion due to free lime (CaO) or magnesia content. 2. Purpose Check dimensional stability of cement Detect presence of free lime (CaO) or magnesia Prevent cracking in concrete structures Ensure compliance with IS 4031 Part 3 and MoRTH specifications 3. Applicable Standards IS 4031 (Part 3) – Soundness test of cement using Le Chatelier method IS 4031 (Part 4) – Standard consistency for paste MoRTH Specifications – Cement quality control 4. Apparatus Le Chatelier Mould (split ring, inner & outer arcs) Vernier Caliper – for measuring expansion Water Bath / Beaker – 27–30°C Glass Plate / Base Plate Mortar Preparation Tools (trowel, spatula) 5. Test Sample Preparation Cement paste is prepared using standard consistency water. Example ratio: 1 part cement : 0.78 parts water (by weight). Sample Preparation Example: For 100 g of cement: Water required = 100 × 0.78 = 78 g Mix cement and water to obtain a uniform paste for filling the Le Chatelier mould. 6. Test Procedure – Le Chatelier Method Preparation of Cement Paste Determine the standard consistency of cement using IS 4031 (Part 4). Mix cement and water (~1:0.78 by weight) to obtain uniform paste. Avoid lumps to ensure accurate test results. Filling the Le Chatelier Mould Clean mould thoroughly and lightly oil to prevent sticking. Fill mould carefully, avoiding air pockets. Tap gently or use spatula to compact paste evenly. Leveling the Paste Level top of paste to match upper rim of mould. Ensure flush surface to avoid erroneous readings. Immersion in Water Bath Place mould in water bath maintained at 27–30°C for 24 hours. Keep undisturbed and maintain constant temperature. Measurement of Expansion Remove mould carefully after 24 hours. Measure distance between indicator arms using vernier caliper. Take measurements to nearest 0.5 mm for precision. Calculation of Expansion Formula: Expansion (mm) = Final distance between arms – Original distance between arms Record mean of two measurements if multiple moulds are tested for accuracy. 7. Acceptance Criteria Maximum expansion for OPC: ≤ 0.8 mm (IS 4031 Part 3) Rapid Hardening Cement: slightly lower limits 8. Engineering Significance Prevents cracks in concrete due to excessive expansion Ensures dimensional stability of cement in structural and pavement applications Critical for highway pavements, bridges, and high-rise concrete structures 9. Common Mistakes Air bubbles while filling mould Incorrect water bath temperature Improper vernier caliper measurement Using non-standard consistency paste Ensure proper handling to avoid false readings; repeat test if inconsistent. 10. Frequently Asked Questions What is the purpose of the Le Chatelier test? It checks cement expansion due to free lime or magnesia, ensuring dimensional stability. Which IS code covers the test? IS 4031 (Part 3) What is the maximum allowable expansion? ≤ 0.8 mm for Ordinary Portland Cement (OPC) How is cement paste prepared? Using standard consistency water; example ratio: 1 part cement : 0.78 parts water by weight. What happens if expansion exceeds the limit? Excessive expansion indicates free lime; cement should be rejected or used with caution in structural work. 11. Conclusion The Soundness Test of Cement – Le Chatelier Method ensures cement stability, prevents cracks, and guarantees compliance with IS 4031 and MoRTH specifications. Always perform this test for critical concrete and pavement works. Written by: Kishor Kumar · Civil / Highway Engineer – QA/QC & Site Execution · Source: HighwayQualityTest.com

Bituminous Concrete (BC) Profile Corrective Course – Construction Methodology | MoRTH Profile Corrective Course Using Bituminous Concrete (BC) – Construction Methodology Bituminous Concrete (BC) Profile Corrective Course is a thin, dense graded bituminous layer laid to correct minor surface undulations, rutting, shallow depressions and riding quality issues prior to or as part of the final wearing course. 1.0 Scope and Surface Preparation This work consists of providing a Profile Corrective Course using Bituminous Concrete of variable thickness, generally ranging from 30 mm to 50 mm, to restore the pavement profile as per approved longitudinal and cross levels. 1.1 Existing Bituminous Surface Repairs: Potholes, cracks, ravelled areas repaired as per MoRTH Clauses 3004.2 & 3004.3. Milling / Scarifying: Where required, shallow milling carried out to remove surface irregularities. Cleaning: Surface cleaned using mechanical broom and air compressor. Tack Coat: Uniform tack coat applied prior to BC laying. 1.2 Existing Granular Surface (If Applicable) Surface made firm, even and free from loose materials. Priming carried out as per MoRTH Clause 502. Tack coat applied after priming and curing. 1.3 Pre-Laying Level Checks Existing levels shall be checked jointly with Engineer’s representative and recorded to determine thickness and extent of profile correction. 2.0 Plant, Machinery & Equipment Sl. No. Equipment Quantity 1 Batch Type Hot Mix Plant (150–200 TPH) 01 2 Sensor Paver with Electronic Screed Control 01 3 Tandem Vibratory Roller 02 4 Pneumatic Tyred Roller 01 5 Bitumen Pressure Distributor 01 6 Mechanical Broom / Air Compressor 01 7 Tipping Trucks As required 3.0 Materials & Mix Design 3.1 Materials Coarse & fine aggregates conforming to MoRTH Table 500-18 Bitumen: VG-30 / VG-40 / Modified Bitumen (as per contract) Mineral Filler: Cement / Lime / Stone Dust Tack Coat: Rapid Setting Cationic Bitumen Emulsion 3.2 Job Mix Formula (JMF) BC mix design shall be carried out using the Marshall Method as per MoRTH Clause 509. Approved JMF shall specify grading, binder content, temperature limits and target density. 3.3 Hot Mix Plant Operation Bitumen temperature: 150–165°C Aggregate temperature: 150–170°C Mix discharge temperature: 140–165°C Uniform coating ensured with controlled mixing time 4.0 Laying & Compaction 4.1 Transportation of Mix BC mix transported in insulated, tarpaulin-covered trucks. Truck beds coated with approved release agent. Temperature at paver hopper: ≥135°C. 4.2 Tack Coat Application Application rate: 0.20–0.25 kg/m² on bituminous surface. Applied by calibrated mechanical sprayer. Laying commenced only after tack coat breaks. 4.3 Laying & Finishing Sensor wire fixed at 10 m intervals for level control. Minimum laying temperature: 130°C. Loose thickness allowance: approx. 20–25%. Manual finishing permitted in confined or irregular areas. 4.4 Compaction Initial rolling by tandem vibratory roller. Intermediate rolling by PTR. Final finish rolling by static tandem roller. Rolling continued till specified density achieved. Transverse joints cut full depth and edges painted with hot bitumen. 5.0 Quality Control & Traffic Management Core cutting after 24 hours for density verification. Marshall properties verified as per approved JMF. Surface regularity and levels checked as per Clause 902. Traffic opened minimum 24 hours after completion. Traffic diversion with barricades, cones and flagmen. Frequently Asked Questions – BC Profile Corrective Course Purpose of BC PCC? To correct minor profile defects and improve riding quality. Typical thickness? 30–50 mm. Where used? Rutting, shallow depressions, uneven surface. Material? Bituminous Concrete as per MoRTH Clause 509. Tack coat rate? 0.20–0.25 kg/m². Compaction? Tandem roller + PTR. Joint treatment? Full depth cut with hot bitumen painting. Traffic opening? After minimum 24 hours.