What are the dimensions of plate glass used in concrete testing?

The correct choice refers to plate glass dimensions that are specifically suitable for concrete testing applications. In concrete testing, particularly when using measuring containers like molds or cylinders, a plate of glass serves an important function: it creates a smooth surface that allows for effective leveling and finishing of the concrete sample.

The specified dimensions of 1/4" thickness provide the right balance of strength without being excessively heavy or difficult to handle. Additionally, having the glass measure be at least 1" larger in diameter than the measuring container ensures that the glass covers the entirety of the container's top surface, which is crucial for preventing contamination and loss of moisture during the curing process.

This particular choice optimally supports the requirements for concrete testing, ensuring that the sample is properly contained and that the glass can withstand handling without risk of breaking. Other options either specify inappropriate thicknesses or insufficient dimensions that would not meet safety and accuracy standards in concrete testing procedures.