Concrete QC — Drilled Core Assessment
Drilled Core Assessment for concrete quality control and investigation work.
Cores judge in-place concrete by a kinder rule — 85% of f'c — because drilling damage, in-situ curing and specimen size all bias low versus a lab cylinder. A 'failing' 26 MPa core against a 30 MPa spec is, by ACI 318's actual criterion, a PASS; this calculator settles that argument.
Formula
Note: Planning estimate only — strength for structural decisions (formwork striking, post-tensioning, loading) must be verified by site-cured specimens or a calibrated maturity system per the project specification.
Drilled Core Assessment for concrete quality control and investigation work. A free concrete curing, maturity & strength tool — no sign-up, no upload, instant results in your browser.
About Concrete QC — Drilled Core Assessment
Concrete QC — Drilled Core Assessment computes the governing relationship f_corr = f_core × k(l/d) [ASTM C42 length-diameter correction] live as you type. Cores judge in-place concrete by a kinder rule — 85% of f'c — because drilling damage, in-situ curing and specimen size all bias low versus a lab cylinder. A 'failing' 26 MPa core against a 30 MPa spec is, by ACI 318's actual criterion, a PASS; this calculator settles that argument. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Concrete QC — Drilled Core Assessment
- 1Enter your values — Core strength (l/d = 2), Actual l/d ratio, Specified f'c (sensible defaults are pre-filled).
- 2Read the live results: Corrected core strength, vs specified.
- 3Check the "with your numbers" line to see f_corr = f_core × k(l/d) [ASTM C42 length-diameter correction] substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Concrete QC — Drilled Core Assessment?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula f_corr = f_core × k(l/d) [ASTM C42 length-diameter correction] with authoritative sources cited on the page (ACI 318 / ASTM C39, C42, C496, C597; IS 456:2000 — Plain and reinforced concrete code of practice; Neville, A.M., Properties of Concrete, 5th ed.)
- ✓Cores judge in-place concrete by a kinder rule — 85% of f'c — because drilling damage, in-situ curing and specimen size all bias low versus a lab cylinder.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the concrete qc — drilled core assessment use?+
It evaluates f_corr = f_core × k(l/d) [ASTM C42 length-diameter correction], exactly as published. Sources: ACI 318 / ASTM C39, C42, C496, C597; IS 456:2000 — Plain and reinforced concrete code of practice; Neville, A.M., Properties of Concrete, 5th ed.. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Cores judge in-place concrete by a kinder rule — 85% of f'c — because drilling damage, in-situ curing and specimen size all bias low versus a lab cylinder. Planning estimate only — strength for structural decisions (formwork striking, post-tensioning, loading) must be verified by site-cured specimens or a calibrated maturity system per the project specification.
When is this calculator the right tool for the job?+
Drilled Core Assessment for concrete quality control and investigation work. A free concrete curing, maturity & strength tool. A 'failing' 26 MPa core against a 30 MPa spec is, by ACI 318's actual criterion, a PASS; this calculator settles that argument. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
Related tools
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- Concrete QC — Rebound Hammer Interpretation
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- Network — Series Airways Resistance
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