CEMENT TESTING EQUIPMENT

In the construction world, cement is considered a binding agent that sets, hardens and adheres to other materials to bind them together. Most notably, cement is a cornerstone ingredient of concrete, which is created by mixing cement, water, aggregates and other additives or admixtures. Cement can also bind with water and sand to create mortar (a thicker material used to bond bricks or masonry units together) and grout (a more viscous material used to fill voids between structural surfaces).

Cement is made by heating limestone, clay, shale and other minerals at high temperatures in a kiln then grinding the resulting product into a fine powder. Mixing this powder with water causes a chemical reaction called hydration, which forms calcium silicate hydrates and gives concrete its strength.

There are many different types of cement with varying strength, durability, setting time and other properties depending on your application. Here are the main types of cement recognized by ASTM:

+ Portland Cement (ASTM C150)

There are five different types of Portland cement with varying levels of sulfate resistance, heat of hydration, and strength.

Sulfate resistance is the ability of cement to withstand the corrosive effects of sulfate ions present in certain environmental conditions. Type II Portland cement has moderate sulfate resistance, while Type V has high sulfate resistance.  

Heat hydration refers to the heat energy released when water is added to cement during hydration (when cement is mixed with water). Type IV has lower heat hydration, which is desirable for applications like mass concrete pours where temperature control is essential to prevent thermal cracking.

+ Blended Hydraulic Cements (ASTM C595)

Blended hydraulic cement is made by blending Portland cement with other cementitious materials (slag, fly ash, clay, hydrated lime, etc) to produce a performance cement. ASTM C595 classifies these cements into two types: Type IS (Portland blast-furnace slag cement) and Type IP (Portland-pozzolan cement).

+ Performance Cements (ASTM C1157)

There are six types of performance categories specified by ASTM C1157, again relating to properties like early strength, sulfate resistance, and heat of hydration:

• GU: General Use
• HE: High Early-Strength
• MS: Moderate Sulfate Resistance
• HS: High Sulfate Resistance
• MH: Moderate Heat of Hydration
• LH: Low Heat of Hydration

Before cement can be used in construction, it must be tested to ensure it meets the required quality and performance standards. In addition to strength, cement is often tested for:

• Air permeability: Air permeability is the ability of cement paste to resist air, informing its fineness and porosity.
• Bleed: Bleeding is the process in which water in the cement mix “bleeds” upward through the cement as a result of heavy particles sinking or settling. A certain level of bleed is tolerable (and, in some cases, desirable), but if your cement bleeds too much, it can adversely affect the material’s durability.
• Water retention: The capacity of cementitious materials to retain water without excessive drying, which is essential for workability and curing.
• Strain: The deformation or elongation of cement under applied stress, indicating its ability to withstand load.
• Consistency: The workability and flow characteristics of cement paste, which influence placement and finishing.
• Mud flow & density: Reflects the flowability, viscosity and weight of cement slurry.
• Setting time: The time it takes for cement to change from a plastic to a hardened state.

Cement testing equipment refers to a range of instruments and apparatuses used to evaluate the properties of cement to ensure quality construction materials (concrete, mortar, grout, etc). Equipment includes:

• Blaine apparatus: draws a known quantity of air through the cement. As the air flows through the cement, you can measure the airflow rate and determine how fine the cement material is.
• Cement bleeding apparatus: analyzes the rate and capacity of bleeding in cement paste and mortar.
• Water retention device: used in specification tests of masonry cement and physical testing of quicklime and hydrated lime.
• Strain gauge: tests the strain level in a cement sample by attaching to cement and vibrating the tensioned wire that runs from one flange to the other with an electromagnet.
• Vicat: measures a cement paste’s consistency level. Forney’s automatic Vicat apparatus can quickly and precisely measure the paste’s setting times, allowing you to perform penetration tests with ease.
• Mortar penetration resistance apparatus: determines the time of setting of concrete, with slump greater than zero by means of penetration resistance.
• Cement molds: used to form samples of cement, mortar cube, and grout cubes to conduct compression tests.
• Test sand: naturally rounded silica sands of nearly pure quartz in three different gradings specifically for ASTM tests. ASTM tests include ASTM C109, ASTM D1556, and ASTM C778.

Cement testing is an important part of construction materials testing, especially when it comes to foundational building materials like concrete. Here are some other helpful resources related to cement testing and equipment: 

• Construction Materials Testing Protocols [Full Listing]
• Glossary of Construction Materials Testing Terms
• Simple Guide to ASTM C1019-20: Sampling & Testing Grout for Masonry