Concrete Curing for 7 Days and Formwork Removal at 30 Hours: Bina Marga Guide
Concrete curing means keeping concrete moist and at a fairly constant temperature so the cement hydrates fully. The Guide for Concrete Works on Roads and Bridges, Pd T-07-2005-B from the Directorate General of Highways (Bina Marga), Ministry of Public Works, gives clear figures: wet covering for at least 7 days, formwork on thin walls and columns not removed before 30 hours, and formwork under slabs and beams waiting for a compressive test of 85% of design strength. This article summarises clauses 4.6, 6.3, 7.3, 8.1, 8.4, 9.1 and 9.2 plus Tables 5 and 6. The guide is for roads and bridges, not houses; for a house the figures can serve as a benchmark, and the final decision rests with the structural designer. Data as of 23 October 2026.
Concrete curing, formwork removal and slump: figures from Pd T-07-2005-B
| Stage | What the guide says | Clause | homeX note | Source |
|---|---|---|---|---|
| Weather when pouring | Pouring must be shielded from direct sun; it must not be done when the evaporation rate exceeds 1.0 kg/m²/hour (ACI 305.R-77 chart), nor during rain or in dusty air; the pour location is kept free of rain with a tent | 4.6 and 7.1 | We did not copy the evaporation chart; the guide only gives the 1.0 kg/m²/hour limit | Kementerian PU (Bina Marga) |
| Pouring | Written notice at least 24 hours before the pour; pouring into the formwork finished within 1 hour of mixing (unless a retarder is used); layers of at most 15 cm for complex shapes or dense reinforcement, up to 30 cm for walls; free-fall height at most 150 cm; no water may flow over the surface in the first 24 hours; old concrete faces are roughened and treated with a tested bonding agent | 7.3 | For ready-mix deliveries, the 1-hour limit has to be compared with the travel time and pump schedule | Kementerian PU (Bina Marga) |
| Planned slump (Table 5) | Walls, foundation slabs and reinforced footings 5.0–12.5; unreinforced footings, caissons and underground works 2.5–9.0; slabs, beams, columns and walls 7.5–15.0; road pavement 5.0–7.5; mass concrete 2.5–7.5; measured slump must not exceed the planned slump by more than 20 mm | 6.3 (Table 5) and 9.1 | Data gap: Table 5 in the PDF copy we read does not print a unit; since the tolerance is written as 20 mm, the unit is probably cm (homeX inference, not data) | Kementerian PU (Bina Marga) |
| Wet curing | Protect the concrete from early drying, excessive heat and mechanical disturbance; start as soon as the concrete begins to harden (before plastic shrinkage cracks) by covering it with water-absorbent material kept saturated for at least 7 days and in contact with the surface; timber formwork not yet removed is kept wet | 8.4 a, b | 7 days is the minimum in this guide, not a quality guarantee; no specific material such as burlap is named | Kementerian PU (Bina Marga) |
| Special cases | A concrete surface used directly as a wearing course is cured with a 5 cm layer of damp sand for at least 21 days; high early-strength cement concrete is kept wet until it reaches at least 70% of the 28-day design strength | 8.4 c, d | Applies to wearing surfaces (e.g. a carport floor without tile cover) and high early-strength cement; the guide does not mention PCC or OPC | Kementerian PU (Bina Marga) |
| Formwork removal | Vertical faces, walls, thin columns and similar must not be stripped earlier than 30 hours after pouring, without neglecting curing; formwork supported by props under slabs, beams, girders or arches must not be removed until a compressive test shows at least 85% of design strength or a calculation shows the load can be carried; exposed surfaces for finishing are stripped 9 to 30 hours after pouring | 8.1 | The 30-hour and 85% figures come from a road and bridge guide; for a house, agree them with the structural designer and test specimen results | Kementerian PU (Bina Marga) |
| 7- and 28-day compressive tests (Table 6) | One pair of specimens for each mix poured, at least one set per grade and per component type cast separately each day; cylinder 15–30 cm minimums: fc 15 MPa 9.5 (7 days) and 14.5 (28 days); fc 20 15.0 and 21.0; fc 25 18.0 and 25.0; fc 30 21.0 and 29.0; fc 35 24.0 and 33.0 MPa; if the 7-day result is below the requirement, pouring stops until the cause is known | 9.2 and 6.3 (Table 6) | Table 6 is the same one discussed in our K-to-fc concrete grade conversion article; here it is used only for the 7-day test limits | Kementerian PU (Bina Marga) |
Source: Pd T-07-2005-B, Guide for Concrete Works on Roads and Bridges, Directorate General of Highways (Bina Marga), Ministry of Public Works (clauses 4.6, 6.3, 7.3, 8.1, 8.4, 9.1, 9.2; Tables 5 and 6). Data gaps: this document is for roads and bridges, not houses; the Table 5 unit is not printed in the copy we read; we did not read SNI 2847 or other concrete SNIs, so no house-specific figures are set; the steam curing clause (8.5) is not covered; no Indonesian weather or temperature data were checked. The document code carries 2005; we did not check whether a newer revision exists. Not engineering advice; consult a structural designer. Data as of 23 October 2026.
How to read the concrete curing figures for a house (homeX analysis)
homeX analysis, not guide data: the guide sets minimums for supervised road and bridge works. For a house slab or beam pour, three things are easiest to check and consistent with the guide: (1) record the mixing time and the finish time of the pour; (2) start covering and wetting as soon as the surface hardens and keep it saturated for at least 7 days; (3) do not remove props under a slab or beam without the designer approval, because the guide requires proof of 85% strength or a calculation. When exactly a slab may be loaded is not set here.
Buyer tips
- Record the mixing time and the finish time; the 1-hour limit in the guide counts from mixing.
- Start wet covering as soon as the surface hardens and keep it saturated for at least 7 days.
- Do not remove props under slabs or beams before the designer approves.
- Make specimens for each grade and pour day; a low 7-day result is a signal to stop and check.
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Disclaimer: prices change without notice and differ by store, city, pack size, grade and promotion. Data as of 23 October 2026; always confirm with the seller before buying.
FAQ
How long is concrete curing per the Bina Marga guide? Clause 8.4 asks for water-absorbent material kept saturated for at least 7 days. A concrete wearing course uses 5 cm of damp sand for at least 21 days, and high early-strength cement concrete is kept wet to 70% of the 28-day strength.
When can formwork be removed? Per clause 8.1, vertical faces, walls and thin columns are not stripped before 30 hours; formwork under slabs or beams waits for a compressive test of at least 85% of design strength or a load calculation.
Does this guide apply to a house slab pour? Not directly: Pd T-07-2005-B is for roads and bridges. Its figures can be a benchmark, but for a house the decision follows the structural designer and building standards we have not read.
Concrete curing: related articles and products
Related articles:
- Concrete Grade K to fc Conversion: K-300 Is About 25 MPa (Bina Marga Table 6)
- Concrete Slab (Cor Dak) Cost per m² 2026: Ready Mix, Rebar, Formwork, Pump
- Ready-Mix Concrete Price per m³ 2026: K-225, K-300 & Minimix
- Practical Column, Sloof and Ring Beam for a House: Rebar and Spacing
- Cement Types in Indonesia: OPC vs PCC vs PPC and When to Use Each
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Price sources (checked 23 October 2026): Kementerian PU (Bina Marga) — Pd T-07-2005-B: Concrete works for roads and bridges (clauses 4.6, 6.3, 7.3, 8.1, 8.4, 9.2, Tables 5 and 6).