IS 10078 : 1982Specification for jolting apparatus for testing cement

IS 10078:1982 is the specification for the jolting apparatus for testing cement — the standardised jolting table that compacts the reference mortar when moulding cement test prisms/cubes, the alternative to the IS 10080 vibration machine and the route aligned with the ISO/EN cement-strength method. Like its vibration-machine sibling, it sits directly under the number that defines cement strength grade.

It sits in the cement-testing stack:

• IS 4031 Part 1 (Part 6 = compressive strength) — physical tests that use the moulded specimens · IS 650 — standard sand for the mortar
• IS 269 — OPC (grade defined by the strength of these specimens) · IS 10080 — vibration machine (the parallel compaction route)

Cement strength is reported on a standard mortar compacted by a standard energy — change the compaction and you change the apparent strength of the same cement. IS 10078 fixes the jolting route:

• A table that lifts the mould a fixed height and drops it ('jolts') a fixed number of times (the classic method: a defined drop through a fixed height, a set number of jolts at a controlled rate) — a repeatable compactive energy
• A rigid frame and mould clamping so all the jolt energy enters the mortar, not the structure
• A controlled drop height and jolt count/rate — the parameters that *are* the standardisation

The engineering point: jolting and vibration are two valid roads to the same end — a standard, fully-compacted reference specimen. What matters is that the chosen apparatus runs to its standardised parameters. A jolting table with a worn cam, wrong drop height or off jolt-count under- or over-compacts the mortar and produces a *machine* error that looks exactly like a cement defect.

Scenario: verify an OPC 43 consignment to IS 269 on 28-day strength using jolting-table moulding.

Step 1 — standard mortar: 1 : 3 cement : IS 650 standard sand, water = (P/4 + 3.0)% per IS 4031 Part 1.

Step 2 — mould on the jolting table: clamp the mould; confirm the drop height and jolt count/rate are within the IS 10078 standard before use.

Step 3 — jolt: introduce the mortar and apply the standardised number of jolts — fixed energy, every batch, identically.

Step 4 — cure & crush: demould at 24 h, water-cure, crush at 3/7/28 d in a calibrated IS 14858-compliant CTM; OPC 43 → ≥ 43 MPa at 28 d.

If the table's drop height or jolt count is off, the 'low' result is the *apparatus*, not the cement — you would reject conforming cement, or pass weak cement if over-compaction flatters it. Same failure mode as a drifting IS 10080 vibration machine.

1. Unverified drop height / jolt count. Worn cams or mis-set parameters change compaction and the reported strength — periodic verification is mandatory.

2. Loosely clamped mould. Energy lost to mould movement under-compacts the mortar → false low strength.

3. Mixing methods within a comparison. Jolting some specimens and vibrating others makes results non-comparable — fix one route for a given comparison.

4. Worn/non-true moulds. Wrong prism/cube dimensions skew the MPa independent of cement or compaction.

5. Non-standard sand/water. Site sand instead of IS 650 sand, or wrong water, invalidates the test whatever the table does.

• IS 4031 Part 1 — physical tests for hydraulic cement (strength uses the moulded specimens)
• IS 10080 — vibration machine for cement mortar cubes (parallel compaction route)
• IS 650 — standard sand for testing of cement
• IS 269 — OPC 33/43/53 (grades defined by this strength test)
• IS 14858 — compression testing machine (crushes the specimens)

IS 10078 is reaffirmed and is the jolting counterpart to IS 10080: two different machines, one job — compact the standard cement mortar by a standardised energy so the strength test fairly grades the cement. The practitioner point is identical to its sibling: when a consignment 'fails' on cube strength, the moulding apparatus is a prime suspect before the clinker — a worn cam, wrong drop height or off jolt count is a machine error wearing a cement defect's clothes. Pick one compaction route for a given comparison, verify the drop height and jolt count periodically, clamp the mould hard, and use true moulds with genuine IS 650 sand. Then the IS 4031 strength is an honest verdict on the cement that goes into your IS 456 concrete.