Highway Engineering/CBR Method Sub-Engineer SSC-JE 🎯 Quick Revision 📚

#sscje #upsc2025 #civilengineering #engineering #shorts📌 What is CBR? California Bearing Ratio (CBR) is a penetration test developed by the California State Highway Dept. to evaluate subgrade soil strength and determine thickness of pavement layers. 🧪 CBR Test Overview Conducted on remoulded soil at 95% compaction & optimum moisture content. Plunger Diameter: 50 mm Penetration Rate: 1.25 mm/min Load Measured for: 2.5 mm penetration 5.0 mm penetration ✅ CBR (%) = (Test Load / Standard Load) × 100 Standard Load (kg): 2.5 mm → 1370 kg 5.0 mm → 2055 kg 🔧 Use the higher value (usually 2.5 mm) for design unless 5.0 mm greater than 2.5 mm 📊 Typical CBR Values Soil Type CBR (%) Clayey soil greater than 5% Sand 10 – 30% Gravel/Crushed rock greater than 30% 📐 CBR Method Application CBR value is used to determine thickness of pavement layers from IRC charts. 📌 IRC:37-2018 is the latest design guideline followed. 🧠 Exam Special Tricks CBR Less than 2% → Very Poor subgrade CBR 2–5% → Poor CBR 5–10% → Fair CBR greater than 10% → Good 💥 High CBR = Less Pavement Thickness 🔍 Example PYQ Style Q: If CBR of subgrade soil is 4%, what does it indicate? A: Poor subgrade (needs thick pavement) 🎯 Rapid-Fire Facts for SSC JE CBR = (Test Load / Std Load) × 100 Test plunger = 50 mm dia Penetration = 2.5 mm & 5 mm IRC-37 used for flexible pavement design CBR test checks subgrade bearing capacity #CBRMethod #HighwayEngineering #SSCJE2025 #SubEngineer2025 #CBRTestExplained #FlexiblePavementDesign #CivilEngineeringMCQ #SSCJEPreparation #EngineeringExamReady #GATECivil2025 #SoilTesting #CBRSoilStrength #IRC372018 #SSCJEHighway #CBRvsThickness #QuickRevisionCivil #EngineerStyleRevision #CivilPYQSession #CBRConceptClear #RoadDesignSSCJE CBR method,CBR test,California bearing ratio,SSC JE highway engineering,Sub engineer civil,Highway engineering SSC JE,Flexible pavement design,IRC 37 2018,CBR method explained,CBR for pavement design,CBR soil testing,SSC JE civil 2025,CBR SSC JE,CBR formula,Highway engineering quick revision,Civil engineering PYQs,SSC JE preparation,CBR pyq questions,Sub engineer exam 2025,Road design CBR method