Parameters

Total weight of the sliding parts, including the test cone: 300 g

The test cone has a large sliding stroke of 70 mm.

Net weight ≈4.2 kg

Instructions

According to GB/T 1346-2001 “Test Methods for Water Requirement of Normal Consistency, Setting Time, and Soundness of Cement Paste,” the Vicat needle method is designated as the representative method for determining normal consistency, while the standard rod method is recognized as the standard method for this determination. Consequently, in routine testing, the Vicat needle method may still be used to measure normal consistency. This set of Vicat needle fixture accessories is primarily intended for use in the standard method of determining normal consistency and for measuring initial and final setting times. When determining the water requirement of normal consistency (standard method) and the setting time of cement paste in accordance with the new standard, only the sliding component of the original setting-time tester needs to be replaced, while the fixed components—namely the support frame and scale—remain unchanged. All components of this Vicat needle fixture set are made of stainless steel, offering superior durability compared with conventional steel parts that have been electroplated in the past. It is suitable for use in the determination of normal consistency and setting times for silicate cement, ordinary Portland cement, slag cement, pozzolanic cement, fly-ash cement, and other types of cement.

1. Sliding rod: 1 piece. φ12 mm +0.02 mm –0.10 mm

2. Standard consistency test rod: 1 piece; effective length: 50 mm ± 1 mm; diameter: φ10 mm ± 0.05 mm.

3. Initial setting test needles: 2 pieces. Effective length: 50 mm ± 1 mm; diameter: φ1.13 mm ± 0.05 mm.

4. Final setting test needle: 1 piece; effective length: 30 mm ± 1 mm; diameter: φ1.13 mm ± 0.05 mm.

5. Reading pointer: one

6. Total weight of the sliding parts: 300 g ± 1 g

1. This Vicat apparatus consists primarily of a cast-iron base, a support frame, a sliding rod, a graduated scale, a circular mold, a test rod, and a test needle. The set-screw adjacent to the sliding rod is used to adjust its height, while the pointer is secured to the sliding rod by a retaining sleeve and screw to measure the movement of the sliding rod.

2. This Vicat apparatus is equipped with a bilateral graduated control scale. Reading is performed by sliding the vernier rod and observing the indicator needle fixed to the rod. The left side of the scale is marked “S,” indicating the sinking depth in millimeters, with a range from 0 to 70 mm and a smallest scale division of 1 mm. The right side of the scale is marked “P,” with graduations from 21% to 33%, representing the water requirement for standard consistency.

3. The standard consistency rod is used for determining consistency, while the test needle is used for determining setting time; both the rod and the needle are detachable to accommodate different testing requirements.

1. Before use, apply a small amount of lubricant to the sliding parts and verify that they can move freely up and down.

2. Determination of standard consistency: Immediately after mixing is completed, the prepared cement paste shall be placed into the test mold positioned on a glass base plate; the paste shall then be tamped with a small knife and gently vibrated several times. Excess paste shall be scraped off, the surface smoothed, and the mold and base plate promptly transferred to the Vicat apparatus, with the center of the mold aligned directly beneath the Vicat rod. The rod shall be lowered until it contacts the surface of the cement paste, the screw tightened, and then abruptly released, allowing the rod to sink vertically and freely into the paste. The distance between the Vicat rod and the base plate shall be recorded when the rod ceases to sink or 30 seconds after the rod is released. After raising the rod, it shall be immediately wiped clean. The entire procedure must be completed within 1.5 minutes after mixing. The cement paste whose Vicat rod sinks to a depth of 6 mm ± 1 mm from the base plate is defined as the standard-consistency paste, and the amount of water used in its preparation is the standard-water requirement for that cement (P), expressed as a percentage of the cement mass.

3. Determination of the Initial Setting Time: The test specimen shall be cured in a humidity-controlled curing chamber until 30 minutes have elapsed after water is added, at which point the first measurement is taken. During the measurement, remove the cylindrical mold from the humidity-controlled curing chamber and place it under the test needle, ensuring that the test needle is in contact with the surface of the cement paste. After tightening the screw, release it suddenly after 1 to 2 seconds, allowing the test needle to sink vertically and freely into the cement paste. Observe whether the test needle ceases to sink, or record the pointer reading 30 seconds after the needle is released. When the test needle has sunk to a position 4 mm ± 1 mm from the bottom plate, the cement is considered to have reached the initial setting state; the time elapsed from the moment all the cement is added to the water until the initial setting state is defined as the initial setting time of the cement, expressed in minutes.

4. Determination of the final setting time: To accurately observe the penetration behavior of the test needle, a ring-shaped attachment is fitted onto the final-setting needle. After completing the determination of the initial setting time, the test mold together with the cement paste is immediately removed from the glass plate by a translational motion, inverted by 180° with the larger-diameter end upward and the smaller end downward, placed on a glass surface, and then transferred to a humidity-controlled curing chamber for continued curing. As the final setting time approaches, measurements are taken every 15 minutes. When the test needle penetrates the specimen by 0.5 mm—i.e., when the ring-shaped attachment no longer leaves a mark on the specimen—the cement is considered to have reached the final setting state. The time elapsed from the moment all the cement is added to water until the final setting state is attained is defined as the final setting time of the cement, expressed in minutes.

5. Precautions for measurement: During the initial measurements, the metal plunger should be gently supported to allow it to descend slowly, so as to prevent the test needle from being bent upon impact; however, the final result shall be determined based on free fall. Throughout the entire testing process, the position of the test needle’s penetration must be at least 10 mm from the inner wall of the test mold. As the initial setting time approaches, measurements shall be taken every 5 minutes; as the final setting time approaches, measurements shall be taken every 15 minutes. Upon reaching either the initial or final setting, a repeat measurement must be carried out immediately. Only when the results of two consecutive measurements are identical may the state of initial or final setting be officially confirmed. Each measurement must ensure that the test needle does not re-enter the original needle hole. After each test, the test needle must be thoroughly cleaned, and the test mold returned to the humidity-controlled curing chamber. Throughout the entire testing procedure, vibration of the test mold must be strictly avoided.