ASTM C1437

Test Method and Procedure for Measuring the Flow of Hydraulic Cement Mortar

Standard Designation: ASTM C1437

Scope

This test method outlines the process for determining the flow of hydraulic cement mortars, including those containing materials other than hydraulic cements. It's designed to measure flow in contexts where mortar water content is regulated to achieve specific flow levels.

Apparatus

1. Flow Table and Flow Mold: Conforming to Specification C 230.

2. Caliper: As per Specification C 230 or a corrosion-resistant caliper marked in millimeters, with a maximum measuring extent of at least 260 mm (10¼ in.).

3. Tamper: In line with Test Method C 109.

4. Trowel: Steel blade, length 100-150 mm (4-6 in.), with straight edges.

5. Straightedge: Steel, minimum length 200 mm (8 in.), thickness 1.5-3.5 mm (0.06-0.14 in.).

Environmental Conditions

• Perform the test in a mixing room with temperature and humidity controlled as per Specification C 511.

Materials

• Hydraulic Cement Mortar, as specified for the particular application being tested.

Procedure

1. Preparation:

   • Clean and dry the flow table.

   • Center the flow mold on the table.

2. Filling the Mold:

   • Place a 25 mm (1 in.) layer of mortar in the mold.

   • Tamp 20 times using the tamper, applying uniform pressure.

   • Add more mortar to fill the mold, repeating the tamping process.

   • Use a straightedge or trowel to level the mortar flush with the mold top.

3. Flow Measurement:

   • Clean the table top, especially around the mold.

   • Remove the mold 1 minute after mixing completion.

   • Drop the table 25 times in 15 seconds (unless specified otherwise).

4. Diameter Measurement:

   • Use the caliper to measure the mortar's diameter along the four lines scribed on the table top.

   • Record each measurement, either in caliper divisions (to one-tenth of a division) or in millimeters.

Calculations

1. Determining Flow:

   • Calculate the increase in average base diameter of the mortar, expressed as a percentage of the original base diameter.

   • Add the four diameter readings for the flow percentage (if using the specified caliper).

   • For other callipers, compute flow percentage by dividing the average of four readings by the original inside base diameter, then multiplying by 100.

Reporting

• Report the flow to the nearest 1%.

Precision and Bias

1. Precision:

   • Single-operator standard deviation: 4% flow.

   • Two tests by the same operator should not differ by more than 11%.

   • Multi-laboratory standard deviation: 11%.

   • Tests from different laboratories should not differ by more than 31%.

2. Bias:

   • No bias statement due to the absence of a suitable reference material for flow determination.

Keywords: Flow, Hydraulic Cement, Mortar

Notes:

• Note 1: The trowel and straightedge specified in Test Methods C 109 and C 185 may be used if they meet the stated straightness criteria.

• Note 2: The precision data is applicable only for tests conducted with a fixed water content and specific cement type. Data from the CCRL Proficiency Sample Program for CS Flow on C 109 mortars has been used for these precision statements.