Physical Testing of Quicklime, Hydrated Lime, and Limestone

The different chemical compounds that fall under the overarching term “lime”—quicklime, hydrated lime (slacked lime), and limestone—are sharply related, with quicklime being produced through the thermal decomposition of limestone (by heating in a kiln) and hydrated lime deriving from the mixing, or “slaking,” of quicklime with water to transform the CaO powder into the slurry, viscous Ca(OH)₂. Dating back in usage to antiquity, lime compounds today find varied usage in iron and steel manufacturing, building construction, wastewater treatment, pulp and paper production, and agriculture.

ASTM C110-20 Standard for Lime

ASTM C110-20 – Standard Test Methods for Physical Testing of Quicklime, Hydrated Lime, and Limestone specifies test methods used to evaluate the physical properties of quicklime, hydrated lime, and limestone. Knowledge of these qualities is essential for the chemicals’ usage, and they also bear importance for the processes by which limestone is broken down into quicklime and quicklime is slaked into hydrated lime.

The tests in ASTM C110-20, through the use of lime samples, can be used to calculate the following:

• Consistency of Lime Putty
• Plasticity of Lime Putty
• Water Retention of Hydrated Lime
• Air Entrainment of Hydrated Lime
• Autoclave Expansion of Hydrated and Hydraulic Lime
• Popping and Pitting of Hydrated Lime
• Slaking Rate of Quicklime
• Dry Brightness of Pulverized Limestone
• Limestone Grindability
• Settling Rate of Hydrated Lime
• Quicklime Residue
• Fineness of Pulverized Quicklime and Hydrated Lime
• Particle Size of Pulverized Limestone
• Density of Hydrated Lime, Pulverized Quicklime, and Limestone
• Specific Surface Area of Hydrated Lime

The methodology for these tests and the procedures for reporting their observations are detailed in the ASTM C110-20 standard.

Formation of Limestone, Quicklime, Slaked Lime

For an overview of the formation of limestone, quicklime, and slaked lime, as well as a comparison of their properties, please view the following animation:

Calcium Oxide Uses and History

Quicklime and slacked lime have played instrumental roles throughout history for construction, illuminating stages, and even warfare. While contemporary usage of these compounds has abandoned the more-barbaric practices of the past, quicklime and slacked lime are still integral to many industries. If you are interested in reading more about the history of lime and its modern applications, please refer to our past posts on the subject:

Calcium Oxide: From Ancient Warfare to Modern Industry

“In the Limelight” Origin – Quicklime Illumination

Lime in the Pulp and Paper Industry

ASTM C110-20 – Standard Test Methods for Physical Testing of Quicklime, Hydrated Lime, and Limestone is available on the ANSI Webstore.