Last updated February 15, 2026

ASTM C20 Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water

ASTM C20 is a widely accepted standard test method for establishing the apparent porosity, water absorption, apparent specific gravity, and bulk density of fired refractory bricks and shapes by the boiling water method. These values are critical in measuring the quality, durability, and performance of refractory products operating in extreme industrial conditions.

Read More

GET STARTED


    ASTM C20 Introduction

    Refractory shapes and bricks are engineered to sustain temperature, corrosive environments, and mechanical stress in various industries like steelmaking, glass production, and cement manufacturing. Accurate characterization of these materials’ physical properties helps ensure reliability and durability. ASTM C20 provides a precise method of testing essential parameters like apparent porosity, water absorption, apparent specific gravity, and bulk density by a systematic boiling water test. This process facilitates the determination of material integrity, structural flaws, and application appropriateness.

    Get Certified ASTM C20 Testing for Uncompromising Quality and Project Success

    Issuing ASTM C20 certification shows that refractory braces and shapes comply with rigorous physical property standards in the construction of industrial furnaces. Testing is done under controlled conditions in accredited laboratories, and reports are issued that confirm the values of porosity, density, and absorption. The certification enhances the credibility of suppliers, facilitates project approvals, and mitigates the risk of premature refractory failure in very critical thermal installations.

    Service NameRemarks
    ASTM C20 TestingContact US

    ASTM C20 Testing Procedure and Requirements

    Apparent PorosityThe sample is dried, weighed, and then boiled in water. After cooling, the specimen is weighed while suspended in water and then in air to calculate apparent porosity.
    Water AbsorptionThe increase in specimen weight after boiling in water and cooling indicates water absorption. This is expressed as a percentage of the dry weight.
    Apparent Specific Gravity and Bulk DensityCalculations are based on dry weight, suspended weight, and saturated weight, using formulas provided in ASTM C20 to determine density-related properties.

    Scope of ASTM C20

    • Gauges the apparent porosity of refractory brick and shapes that have been burned.
    • Determines water uptake following boiling immersion.
    • Figure out the bulk density in order to assess the structure.
    • Determines the apparent specific gravity of material characterization.
    • Helps in the control of quality and in the comparison of products.

    ASTM C20 Equipment and Sample Preparation

    Drying OvenThe specimens are dried in an oven at a specified temperature (usually around 110°C) to remove all moisture before testing.
    Balance with Adequate PrecisionA high-precision balance is required to record dry weight, suspended weight in water, and saturated weight for accurate calculations.
    Boiling Water Apparatus and ContainerThe specimen is boiled in distilled water for a set duration (commonly two hours), followed by cooling in water to ensure complete saturation.

    Use of ASTM C20

    • Quality assurance in refractory manufacturing
    • Verification of supplier compliance with specifications
    • Performance assessment for furnace linings
    • Comparative evaluation of refractory materials
    • Research and development of improved formulations

    Common Challenges and Troubleshooting in ASTM C20

    Incomplete boiling can trap air inside pores and distort porosity results. Technicians ensure steady boiling and proper immersion depth. Surface water residue can increase saturated weight. Analysts wipe excess water carefully without extracting absorbed moisture. Irregular specimen geometry can affect suspended weight readings, so precise cutting and handling improve accuracy.

    ASTM C20 Aggregate Testing Technique, Process, and Data Collection

    Technicians record three primary weights: dry weight, saturated weight, and suspended weight. They use these values in standard equations to compute apparent porosity, water absorption percentage, bulk density, and apparent specific gravity. Careful data logging ensures traceability and repeatability. Consistent temperature control during boiling and cooling strengthens data reliability.

    Analysis Results and Interpretation for ASTM C20

    Higher apparent porosity indicates greater open pore volume, which can reduce strength and increase slag penetration risk. Lower bulk density often signals lightweight or insulating characteristics. Water absorption values reveal pore connectivity. Engineers interpret these parameters together to assess suitability for specific furnace zones and thermal loads.

    Problem and The Solution for ASTM C20

    The problem arises when refractory bricks show excessive porosity, which can shorten service life. Manufacturers adjust raw material grading, pressing pressure, and firing temperature to reduce pore volume. Accurate ASTM C20 testing identifies such deviations early and supports corrective production control.

    Factors to Consider Us To Test For ASTM C20

    Speed

    Fast turnaround supports project timelines and production release schedules.

    Expert

    Experienced technicians ensure precise measurements and correct calculations.

    Cost

    Competitive testing cost allows routine quality monitoring without increasing production expenses.

    Process for testing
    • STEP 01

      You share your testing requirements

    • STEP 02

      You share your sample(s)

    • STEP 03

      We deliver your test reports

    Get your testing done

    Let us known your testing requirements and we will be right back with a solution.



      Let us root for each other. Collaborate to grow, expand, and accelerate our businesses.

      Partner with us





        close

        Please share your requirement with us

          ×

          Contact Us