Toolchest · Datasheet

Accumath Toolchest — Rebar Grades & Types: Notes

Dataset file: accumath-rebar-grades.csv Built: 2026-10-20 Companion dataset: accumath-rebar.csv (bar sizes #3–#18 — diameters, areas, weights; this file deliberately carries no size geometry beyond bar-number references in elongation classes).

This file records specification minimums by spec, grade and type — yield, tensile, elongation — plus coating requirements for coated bars and guaranteed properties for FRP bars. Every value was taken from a published producer/industry table that republishes the specification minimums; the source column names the table for each row. The ASTM documents themselves were not copied. Where a source publishes only one unit system, the other unit cell is blank — never converted by hand.

How to read the columns

min_yield_ksi / min_yield_MPa, min_tensile_ksi / min_tensile_MPa — specification minimums. For FRP rows the tensile values are guaranteed tensile strengths (see FRP section); there is no yield, so the yield cells are blank on purpose.
min_elongation_pct + elongation_basis — elongation depends on bar size in every steel spec, so each steel row is scoped to a size class and the basis states it (always "in 8 in. [200 mm]" unless noted). For FRP rows the cell carries the published ultimate tensile strain at rupture, and the basis says so — FRP has no elongation requirement of the steel kind.
max_yield_ksi / max_yield_MPa — only where the spec caps yield (A706; A955 Supplementary Requirement S2; A706 Grade 100).
carbon_equiv_max — A706 only (0.55%).
coating — A767/A775 rows only.
tensile_modulus_ksi / tensile_modulus_GPa — added for the FRP rows; modulus is a defining property for FRP and is meaningless as a per-grade variable for steel (29,000 ksi for all grades).

The types, in plain terms

A615 — carbon steel (the default bar). Plain carbon-steel bars, no chemistry control aimed at welding, no cap on actual yield. Cheapest and most available; marked "S". If it might be welded, the spec itself warns to approach with caution.

A706 — low-alloy, weldable (the seismic bar). Same nominal grades as A615 (60, 80) but with two controls A615 lacks, and together they are the whole point of the spec: 1. Carbon equivalent ≤ 0.55% (plus capped carbon, manganese, phosphorus, sulfur, silicon in the chemistry table) — this is what makes the bar reliably weldable without heroic preheat. 2. A maximum yield strength — Grade 60 must land between 60 and 78 ksi; Grade 80 between 80 and 98 ksi. Seismic design (capacity design) needs to know how strong the bar can actually get, because the plastic hinge and everything downstream are sized off the real yield, not the nominal. A615's uncapped yield can overrun the design assumption; A706's cannot. A706 also requires tensile strength ≥ 1.25 × the actual yield strength, guaranteeing strain-hardening headroom in the hinge. Bars are marked "W".

A1035 — low-carbon chromium steel (the high-strength corrosion-resistant bar). Grades 100 and 120 only. Corrosion resistance comes from chromium in the steel (three alloy types — CL, CM, CS — defined by chromium content range in the spec's chemistry table), not from a coating. There is no yield plateau: yield is defined by the 0.2% offset method. Tensile minimum is 150 ksi for both grades; the types share identical mechanical minimums, so the CSV repeats them per type rather than pretending they differ. Welding caution applies — the spec includes no weldability provisions.

A955 — stainless steel. Grades 60/75 (Grade 80 in recent editions). The spec does not fix one alloy: the chemistry is chosen by agreement between producer and purchaser for the application. Typical alloys named in the spec's Table 2: XM-28 (UNS S24100), XM-29 (S24000), 304 (S30400), 316L (S31603), 316LN (S31653), and duplex S31803 (the 2205 family); producers (e.g. Outokumpu) also offer 2304 and lean duplex LDX 2101 in Grade 75. Elongation minimum is a flat 20% in 8 in. for all sizes — much more ductile on paper than carbon bar. Optional Supplementary Requirement S2 gives controlled mechanical properties (a capped yield range and a 1.25 minimum actual TS/YS ratio) — functionally the stainless answer to A706, and recorded as separate rows.

A767 — zinc-coated (galvanized). A coating spec, not a steel spec. It sets zinc coating mass by class: Class I = 3.00 oz/ft² for #3 bars, 3.50 oz/ft² for #4 and larger; Class II = 2.00 oz/ft². Strengths follow the base bar — the bar under the zinc must meet A615, A706 or A996 as ordered, and ACI's summary table states it flatly: A767 bars are "same as A615/A706 bars" for strength. The CSV therefore records coating data on the A767 rows and no invented strengths.

A775 — epoxy-coated. Also a coating spec (fusion-bonded epoxy over an A615/A706/A996 base bar); strengths likewise follow the base bar. Coating thickness after curing, current edition (A775/A775M-22): 7–12 mils [175–300 µm] for #3–#5, and 7–16 mils [175–400 µm] for #6–#18. Note this corrects the "8–12 mils typical" figure in the original task brief — 8–12 mils is the AASHTO M 284 band quoted in FHWA review guidance, not the A775 requirement; older A775 editions held all sizes to 7–12 mils, and the 16-mil upper allowance for large bars is the current text, confirmed independently by the FHWA/JTRP synthesis comparison table and the TxDOT alternate-reinforcement report.

⚠️ Edition change inside A615 — read this before using the A615 rows

The dataset carries two labeled blocks for A615, because the spec changed underneath the industry:

Five-grade editions (through A615/A615M-16): Grades 40, 60, 75, 80, 100 with tensile minimums 60 / 90 / 100 / 105 / 115 ksi. These are the values in every producer comparison chart in circulation (Harris Supply chart; industry mechanical-requirements tables) and are the first block of rows.
Current editions (A615/A615M-22, -26): Grade 75 is gone from the main specification (removed in the -20 edition; it survives only via Annex A2 for other applications), and the specified tensile minimums were lowered — Grade 60: 90 → 80 ksi [550 MPa]; Grade 80: 105 → 100 ksi [690 MPa] — with a new floor on the ratio of actual tensile to actual yield strength (≥ 1.10) doing part of the work the old specified tensile used to do. Grades 40 (60 ksi) and 100 (115 ksi) are unchanged. Source for the current block: ACI PRC-439.4-25, Table 3.1, which summarizes current ASTM minimums.

Practical consequence for QA: an MTR evaluated against a current-edition A615 Grade 60 purchase order can legitimately show a specified tensile minimum of 80 ksi. Rejecting it against the old 90 ksi figure — or accepting a Grade 75 bar against a spec edition that no longer contains Grade 75 — is an edition error, not a material defect. Check the edition on the PO.

FRP bars (scope addition) — what the sources actually say

ASTM D7957 covers glass only. Its title is "Standard Specification for Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement." It contains no grades — one property set: tensile modulus ≥ 44,800 MPa [6,500 ksi], ultimate tensile strain ≥ 1.1%, and tensile capacity specified as a guaranteed ultimate tensile force per bar size (Table 3: #2 = 6.1 kip … #10 = 98.2 kip — reproduced in the D7957 floor row's notes rather than divided into stresses here). The Grade I / II / III families are CSA S807 grades (Canadian), not ASTM grades — producers cite them alongside D7957 (e.g. Pultrall's V-ROD lists CSA S807 Grade III and MTO Grade III; Owens Corning's Greenbar2X lists CSA S807 Grade I), and the grade a product claims under S807 is a modulus/strength class of that standard. The CSV does not present S807 grades as D7957 grades.

Basalt DOES have an ASTM product spec — since 2023. The working assumption that "no ASTM standard governs BFRP" is out of date: ASTM D8505/D8505M-23, "Standard Specification for Basalt and Glass Fiber Reinforced Polymer (FRP) Bars for Concrete Reinforcement," covers basalt and glass straight bars. Its qualification floor is notably stiffer than D7957: mean tensile modulus ≥ 60,000 MPa [8,700 ksi] (vs 44,800 MPa for D7957), mean ultimate tensile strain ≥ 1.1%, mean transverse shear ≥ 152 MPa [22 ksi], guaranteed tensile force per Table 3, with tensile strength a "report value." Bent bars, hybrid-fiber bars, and any fiber other than glass or basalt are expressly out of scope. Florida DOT's Section 932-3 work (2020) predates D8505 and treated BFRP with the D7957-style load table; that is now superseded by a real product standard. ACI CODE-440.11-22 is the design code, and it covers structural concrete reinforced with GFRP bars complying with D7957 specifically — designing BFRP or CFRP to it is an extrapolation the code does not itself make.

CFRP has no ASTM bar product spec. D7957 is glass-only and D8505 §1.6.2 excludes fibers other than glass or basalt. The CFRP rows are therefore producer data only (Hughes Brothers Aslan 200, the long-standing US product): guaranteed tensile 325/315/300 ksi for #2/#3/#4, modulus 18,000 ksi [124 GPa] — about 62% of steel, far stiffer than glass or basalt bar, still not steel.

Producer-data honesty flags in the FRP rows: - Aslan 100 (GFRP) and Aslan 200 (CFRP) values are guaranteed properties (producer defines guaranteed as lot mean − 3σ per ACI 440.1R) — comparable in spirit to a spec minimum. - The Bastech (BFRP) values are mean experimental properties, and the producer's own manual says so in bold terms and points designers to separate guaranteed properties. They are recorded as published and flagged in every BFRP row; do not use them as design minimums. - Aslan 100 sizes #11–#13 are listed by the producer but expressly not guaranteed (a valid ASTM D7205 bar break cannot be achieved) — recorded as a note row with no values. - Guaranteed tensile strength falls as bar size grows in every producer's table (Aslan GFRP: 130 ksi at #2 → 80 ksi at #10). That is a real published property of pultruded bar, not a data error.

Defining behavioral differences (all FRP): no yield point — the stress-strain curve is linear-elastic to rupture, so there is no ductility reserve of the steel kind and the yield columns are blank by design; modulus is roughly ¼ to ⅓ of steel for glass (6,500–8,700 ksi vs 29,000 ksi), somewhat higher for basalt, ~⅔ for carbon; bars cannot be field-bent — bends are factory-formed during manufacture before the resin cures; density is roughly ¼ of steel (BFRP producer figure 1.9–2.1 g/cm³); the bars do not corrode, are electrically non-conductive and non-magnetic (the MRI/telecom/magnetic-levitation niche), and cannot be welded.

Conflicts found and how they were settled

Punchlist Zero's strength chart prints Grade 40 yield/tensile as "40 / 70" ksi while its own article text says Grade 40 tensile is 60,000 psi. The chart is internally inconsistent; 60 ksi (Harris chart + industry table + every edition of the spec) is recorded.
Secondary summaries listing A615 Grade 80 tensile as 100 ksi [690 MPa] (e.g. SourceBySpec's guide) are printing the current-edition value against the five-grade lineup. Both blocks are in the CSV, labeled by edition, so the conflict is preserved rather than resolved by stealth.
A706 Grade 80 maximum yield in MPa: ACI PRC-439.4-25 prints 98,000 (670); A706M-derived tables print [675]. The CSV records ACI's (670) with ACI as the cited source; the [675] variant is noted here.
Harris Supply's 2011 chart shows an A615 "Grade 100" column at 120 ksi tensile — but Grade 100 did not enter A615 until 2015. The chart's high-strength columns predate standardization; the standardized minimum (115 ksi [790 MPa]) is recorded.
A775 thickness "8–12 mils" in the task brief is the AASHTO M 284 acceptance band, not A775's requirement range (7–12 / 7–16 mils by size). Corrected above with two independent published confirmations.

Gaps (deliberate blanks)

A615 Grade 75 and Grade 80 tensile in MPa — the five-grade-era dual-unit values ([690] / [725]) were not printed by any republisher actually opened in this pass (producers publish these grades in ksi; the dual-unit summaries found print current-edition values). Cells left blank rather than converted. Yield MPa for both grades is published (grade designations [520] / [550]) and is recorded.
A706 Grade 100 elongation — strengths are published in ACI's summary; size-class elongations were not captured from an opened producer table.
A955 Grade 80 elongation — Iowa DOT's republished A955 table stops at Grade 75; ACI's summary gives strengths only.
A1035 chromium content ranges per type (CL/CM/CS) — the types are defined by chromium range in the spec's chemistry table, which no opened producer source republishes numerically; the dataset states the types differ by chromium range without inventing the ranges.
Owens Corning PINKBAR+ per-size values — its data sheet's property table did not extract completely in this pass; the complete per-size GFRP table was instead taken from Hughes Brothers' Aslan 100 sheet (a fuller table from an equivalent D7957 producer), cross-checked against Owens Corning's Greenbar2X sheet for #3–#5 (120/108/94 ksi — agrees with the D7957 Table 3 forces divided by nominal area, and with Aslan's #3 value; Aslan's #4/#5 run 2–11 ksi higher as product-specific guarantees).
CSA S807 grade minimums — referenced by producers but not tabulated here; this dataset's scope is the ASTM specs plus producer data.

Sources (as cited per row)

Harris Supply Solutions, Concrete Reinforcing Bar Products comparison chart (2011) · Industry A615/A706 mechanical-requirements training tables · ACI PRC-439.4-25, Table 3.1 · ANSI webstore, ASTM A706/A706M-08a Table 2 · SourceBySpec, Deformed Rebar Guide · ASTM A1035/A1035M-23a Table 3 as republished in standards previews (iTeh; GSO adoption record) · Iowa DOT Materials IM 452 · American Galvanizers Association, ASTM A767 for Rebar (galvanizeit.org) · FHWA/IN/JTRP-2025/03 synthesis report, Table 2.1 · Basekim epoxy-coated rebar data sheet · ASTM D7957/D7957M-22 Tables 2–3 and D8505/D8505M-23 Table 1 as republished in standards previews (iTeh; ANSI webstore) · Hughes Brothers / Aslan FRP, Aslan 100 and Aslan 200 product data sheets · Pultrall, V-ROD 60 product data sheet (Feb 2025) · Basalt Engineering LLC, Bastech BFRP Design Manual DM-1 v2 · Owens Corning Greenbar2X technical data sheet (cross-check).