Let's break down the question and solve it step by step: --- ### **Question** > Because asphalt is a thermoplastic material that changes viscosity with changes in temperature, the various ASTM viscosity tests must be performed at very specific temperatures. - True - False --- ### **Step-by-Step Explanation** #### **Step 1: Understanding Asphalt** - **Asphalt** is a **thermoplastic material**. - **Thermoplastic** means its properties (like viscosity) change when temperature changes. #### **Step 2: Viscosity and Temperature** - **Viscosity** is a measure of a fluid's resistance to flow. - For thermoplastic materials like asphalt, **viscosity decreases as temperature increases** (it flows more easily when hot). #### **Step 3: ASTM Viscosity Tests** - ASTM (American Society for Testing and Materials) sets standards for testing materials like asphalt. - To get **consistent and comparable results**, viscosity tests **must be done at specific temperatures**. (If not, results would vary just because of the temperature difference.) #### **Step 4: Analyzing the Statement** - The statement says tests **must be performed at very specific temperatures** *because* of asphalt's temperature-sensitive viscosity. - We know this is correct because the results would otherwise not be accurate or comparable. --- ### **Final Answer** **The correct answer is:** - **True** --- ### **Summary** Because asphalt's viscosity changes with temperature, ASTM requires tests at specific temperatures to ensure consistent, reliable results. So, the statement is **True**.