Cement Testing

Compressive Strength of Hydraulic Cement Mortars Using 2″ Cube Specimens

Cube specimens are cast and three are tested at each of 1, 3, 7, and 28 days of curing. Samples are cured for the first 24 hours in a standard moist room, and all subsequent days in saturated lime water.

Standard Test Methods for Chemical Analysis of Hydraulic Cement

A variety of chemical testing methods are described. Testing covers all relevant chemical compounds required in most specifications.

Autoclave Expansion of Hydraulic Cement

Prisms are cast, and after 24 hours of curing, the lengths are measured. They are subsequently subjected to multiple hours of elevated temperature and pressure in an ASTM C151 compliant autoclave. Cement prisms are then cooled and measured. The length change is then compared with the initial length and compared to any relevant specification.

Air Content of Hydraulic Cement Mortar

Mortar is cast to the desired consistency, and it is consolidated in a 400mL brass measuring container described in ASTM C185. The weight/volume is determined, and the air content is calculated based on the mix proportions.

Time of Setting of Hydraulic Cement Pastes by Vicat Needle

Cement is cast to normal consistency per ASTM C187. After initial readings, cement paste is left in the Vicat Apparatus and allowed to cure until readings indicate initial set of the Vicat Needle. Sample is allowed to cure until no visible markings are made by the needle, and this is determined to be final set.

Fineness of Hydraulic Cement Powder by Blaine Fineness Apparatus

A cement powder is compacted in a calibrated container. The container is sealed onto the apparatus, and air is allowed to be pulled through the compacted specimen. The rate of hydraulic fluid forced through the system is compared with that of a calibration cement, and the fineness of the cement is determined.

Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)

Mortar bars are cast from the cement/aggregate combination in question. The lengths are measured, and they are stored in appropriate containers submerged in water at the desired test temperature. Length change measurements are recorded for 14 days and may be continued for up to 12 months or more if desired.

Early Stiffening of Hydraulic Cement Mortars Using Vicat Needle

Cement mortar is cast to a specified consistency and consolidated in the C359 container. The vicat apparatus is used to measure penetration resistance at 3, 5, 8, and 11 minutes while the sample is allowed to cure in laboratory air. The material is then re-mixed, and the initial reading is performed again. Early stiffening amount, average early stiffening rate, and early stiffening recovery are reported.

Early Stiffening of Hydraulic Cement Pastes Using Vicat Needle

Cement paste is cast to a specified consistency. Sample is allowed to cure in standard laboratory air for 5 minutes, and retested. Sample is then re-mixed, and the initial reading is taken again. Values for % final penetration and re-mix penetration are reported.

Heat of Hydration of Hydraulic Cementitious Materials Using Isothermal Conduction Calorimetry

An isothermal heat conduction colorimeter is a constant-temperature heat sink, to which two heat-flow sensors and sample holders are attached. One is attached to the sample and one to a reference cell. The heat of hydration can be measured by the calorimeter for up to 7 days to confirm compliance with specifications.

Sulfate Resistance by Percent Expansion of Mortar Bars Exposed to Sulfate

Mortar bars are cast with a gypsum addition to the cement. The lengths of samples are measured and they are allowed to cure in standard lime water. Length comparitor measurements are taken after 14 days of immersion.

Time of Setting of Hydraulic Cement Pastes by Gillmore Needle

Paste is caste to the desired consistency and placed in each section of the Gillmore apparatus. The Gillmore needles are used to determine when the initial and final set have occurred.