LimsPulse
Construction materials testing

Vicat Apparatus

A weighted sliding rod with interchangeable plunger and needles used to find the standard consistency of cement paste and its initial and final setting times.

  • Cement manufacturing
  • Construction materials testing
  • Ready-mix concrete
  • Admixture manufacturers
  • Academic labs
Photo of a Vicat Apparatus
Photo: Habib M’henni, CC BY-SA 3.0 (cropped), via Wikimedia Commons
LEARN & PRACTICE

Test your Vicat knowledge

Multiple-choice questions

Pick an answer to see whether you are right and why.

  1. Q1. Which Vicat attachment is used to find standard consistency of cement paste?

    basic

  2. Q2. Under IS 4031 Part 4, the paste is at standard consistency when the plunger stops at what distance from the bottom of the mould?

    basic

  3. Q3. Standard consistency is 30%. How much water is used for 400 g of cement in the setting-time test?

    intermediate

  4. Q4. For ordinary Portland cement, IS 269 typically requires:

    intermediate

  5. Q5. What is the typical total mass of the Vicat moving rod with its attachment?

    intermediate

  6. Q6. Setting times in your lab are suddenly much shorter than usual for the same cement. Which is the most likely cause?

    advanced

Viva questions

Think of your answer first, then open it to compare.

  1. 1. Define initial and final setting time.

    Initial setting time is the time from adding water until the paste starts to lose plasticity: the 1 mm needle can no longer pierce to within about 5 mm of the bottom of the mould. Final setting time is when the paste has hardened enough that the needle marks the surface but the collar does not.

  2. 2. What do you check in a Vicat needle and plunger dimension check?

    Plunger diameter and length, initial needle section, length and straightness, final needle collar diameter and needle projection, total moving mass, scale zero and graduation, and mould dimensions, all against the apparatus standard or SOP.

  3. 3. Why is gypsum added to cement, and how would its absence show in a Vicat test?

    Gypsum controls the rapid reaction of tricalcium aluminate with water. Without enough gypsum the paste can stiffen almost immediately (flash set), giving an extremely short initial setting time in the Vicat test.

In LimsPulse · Calibration Management

Keep every Vicat in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how