Overview
ISO 1920-14:2019 specifies a standardized method to determine the setting time of concrete mixtures (slump > 0) by measuring the resistance to penetration of mortar sieved from the fresh concrete. The method defines initial and final setting times based on penetration-resistance thresholds and can be used in both controlled laboratory and field conditions to assess the influence of variables such as temperature, cement type/content, mix proportions and admixtures.
Key topics and technical requirements
- Scope: Applies to mortar obtained by sieving concrete through a 5 mm (or 4.75 mm) sieve; suitable for concrete with slump greater than zero.
- Definitions:
- Initial setting time: elapsed time after water–cement contact until mortar reaches 3.5 N/mm² penetration resistance.
- Final setting time: elapsed time until mortar reaches 27.6 N/mm² penetration resistance.
- Specimen preparation:
- Obtain representative concrete sample; sieve to collect mortar, mix, measure temperature, place in rigid watertight containers.
- Container minimum dimensions: lateral ≥ 150 mm and height ≥ 150 mm; mortar depth ≥ 140 mm.
- Apparatus:
- Penetration resistance apparatus (spring or hydraulic) with accuracy ±10 N; removable needles with bearing areas 645, 323, 161, 65, 32, and 16 mm².
- Needles penetrate to 25 mm depth; typical penetration time ≈ 10 s.
- Storage and environmental control:
- Laboratory: store at 20 °C ± 2 °C (or 27 °C ± 2 °C for tropical countries) and relative humidity >65%, or as required by user/national standards.
- Field: store under ambient, shielded from direct sunlight.
- Test schedule and frequency:
- Normal mixes: first test at 2–3 h post-mixing, then hourly.
- Accelerated: first test at 1–2 h, subsequent tests at 30 min.
- Retarded/low-temperature: first test may be 4–6 h or later.
- Minimum six penetrations per hardening rate test; continue until ≥27.6 N/mm² achieved.
- Data handling:
- Plot penetration resistance (N/mm²) vs elapsed time (min); determine times where 3.5 and 27.6 N/mm² are reached (report to nearest 5 minutes). Log–log regression methods permitted.
Applications and who uses it
- Quality control and research for concrete producers, testing laboratories, materials engineers, and contractors.
- Evaluating effects of cement type, admixtures, temperature and mix adjustments on setting and early hardening.
- Useful for mix design validation, troubleshooting early-age performance, and assessing suitability for formwork removal or finishing operations.
Related standards
- Part of the ISO 1920 series (Testing of concrete). Refer to other ISO 1920 parts and applicable national standards for complementary concrete test methods and local environmental/testing requirements.
Keywords: ISO 1920-14:2019, setting time, penetration resistance, concrete testing, mortar, initial setting time, final setting time, concrete mix, admixtures, concrete laboratory test.
Open preview (PDF)Testing of concrete — Part 14: Setting time of concrete mixtures by resistance to penetration
