Toolchest · Datasheet

Concrete — Typical Reference Data (Accumath Toolchest)

Read this first. Concrete is not a fixed material. The same nominal mix can test at different strengths depending on the cement and aggregates actually used, the water actually added, how it was placed and cured, the weather during the pour, and how the test cylinders were made and broken. Every value in this dataset is a published typical or reference value for preliminary work and education only. These are not design values, and they are not a substitute for an approved mix design submittal and cylinder test results for any real structure. Where a source published a range, the dataset records the range. Where no source published a value, the cell is blank — nothing here is interpolated, estimated, or computed from a formula.

Dataset file: accumath-concrete.csv — 52 data rows, 15 columns, grouped by a section column. The basis column on every row states what kind of number it is (typical published value, published guidance value, published durability requirement, published producer data, or published classification) so a typical value can never be silently read as a design value.

Sections

Section	Rows	What it is
strength_class	8	Normal-weight concrete by specified f'c: 2,500 / 3,000 / 3,500 / 4,000 / 4,500 / 5,000 / 6,000 / 8,000 psi
field_guidance_slump	6	Recommended slump ranges by element type (ACI 211.1 Table 6.3.1, republished)
field_guidance_air	7	Target total air content by nominal maximum aggregate size, exposure classes F1 vs F2/F3 (ACI 318-14 Table 19.3.3.1, via NRMCA)
field_guidance_exposure	4	Freeze-thaw exposure-class durability limits: max w/cm and minimum f'c (ACI 318-14 Table 19.3.2.1, via NRMCA) — code minimums, not strength typicals
field_guidance_cold	4	Minimum concrete temperature as placed, by section size (NRMCA CIP 27 / ACI 306 table)
field_guidance_hot	2	Maximum fresh concrete temperature at placement, and the evaporation-rate precaution threshold
fiber_reinforcement	4	Published producer dosages: synthetic microfiber (mono- and fibrillated), macrosynthetic, steel fiber
wwr_styles	9	Common welded wire reinforcement sheet styles (ASTM A1064) with steel area per foot of width
admixture_c494	8	ASTM C494 admixture types A–G plus Type S, one published-effect line each

Field variables — the numbers move on site

The strength-class values in this dataset are lab/reference-basis values: they assume standard curing (moist curing at about 73 °F, the condition the underlying sources state for their strength relationships) and concrete tested as specified. Field concrete does not live in that world. Ambient temperature, humidity, wind, haul time from the plant, and water added at the truck all move the result:

• Temperature and set time. Cold concrete sets slowly and gains strength slowly; hot concrete sets fast and can lose slump before it is placed. A published rule of thumb in cold-weather guidance: a 20 °F drop in concrete temperature roughly doubles setting time. Hot weather accelerates slump loss and shortens the finishing window.
• Humidity, wind, and evaporation. When the evaporation rate from the surface exceeds about 0.20 lb/ft²/h (the ACI 308R criterion as published in producer hot-weather guidance), the surface dries faster than bleed water replaces it and plastic-shrinkage cracking follows. Heat alone doesn't trigger this — heat plus low humidity plus wind does.
• Haul time and site water. Every gallon of water added on site to restore slump raises the water-cement ratio and lowers the strength the lab table promised. The w/c values in this dataset are what the mix was designed to — not what arrived if water was added at the chute.
• Cold weather (NRMCA CIP 27). Cold weather is defined as a period when the average daily temperature falls below 40 °F for more than three successive days. Plastic concrete can freeze below about 25 °F, and concrete frozen early can lose more than 50% of its potential strength. Published practice: protect concrete from freezing until it reaches 500 psi (about 2 days at 50 °F), and protect saturated young concrete from freeze-thaw cycles until it reaches 3,500 psi. Minimum concrete temperatures as placed are in the CSV by section size (55 °F for sections under 12 in., down to 40 °F for mass sections over 72 in.); placed temperature should not exceed those minimums by more than 20 °F. In large sections, a surface-to-interior temperature difference over roughly 35 °F risks thermal cracking.
• Hot weather. Maximum fresh concrete temperature at placement/discharge: 95 °F (ACI 305R limit as published in CEMEX USA hot-weather guidance; ACI 305.1-14 states the same discharge limit in industry guidance). The precautions — shade aggregates, cool mix water, shorten haul, schedule pours early — apply well below that limit whenever evaporation is high.

Where the sources give prose guidance without numbers, this file summarizes the prose. No field number in the CSV or these notes was quantified by us.

Strength-class table — sources and decisions

• Water-cement ratio is from ACI 211.1 Table 6.3.4(a) (approximate compressive strength vs. w/c), as republished in open mix-design guidance and cross-checked against ACI PRC-211.1-22 excerpts. The table is published in 1,000-psi steps from 2,000 to 6,000 psi. 2,500 / 3,500 / 4,500 psi w/c cells are blank — interpolating between published steps would be fake precision. 8,000 psi is blank — outside the table's range. One flag, recorded in the CSV rather than resolved: the 6,000-psi air-entrained value prints as 0.32 in the cited republication and 0.33 in some other reproductions.
• Cement content is the weakest column in the table, and the notes on each row say why. No NRMCA/PCA "typical cement content by strength" table was found. What exists in open sources is producer batch tickets and DOT mix-class tables: 3,000 psi = 511–517 lb/yd³ (one producer ticket; Michigan DOT Grade P2), 3,500 psi = 470–658 lb/yd³ (Michigan DOT classes P1M and P-NC, with a producer ticket at 553 inside the span), 4,000 psi = 624 and 4,500 psi = 702.5 lb/yd³ (single producer tickets each — recorded as published, flagged as single-source in the row notes). 2,500 / 5,000 / 6,000 / 8,000 psi are blank: no published typicals found in the scoped sources.
• Mix proportions by weight (cement : sand : coarse aggregate) come from the same producer's published batch tickets and exist only for 3,000–4,500 psi. The 4,500-psi ticket used 3/8-in coarse aggregate only — flagged in the row.
• Modulus of elasticity (Ec) and modulus of rupture (fr) are blank in every row — deliberately. ACI 318 defines both by equation only (Ec = 57,000√f'c; fr = 7.5λ√f'c for normal-weight concrete). After an extensive search, no NRMCA, PCA, DOT, or university-extension publication in the open sources prints a per-strength Ec or fr table. The build rule for this dataset is published values only; a formula output is not a published value, so the columns stand empty rather than computed. Any future fill must come from a published table that prints the numbers.
• Unit weight is 140–150 lb/ft³ (145 typical) for normal-weight concrete, all rows, from The Engineering ToolBox's published concrete properties — sources publish this as a class property of normal-weight concrete, not per strength, so it is recorded the same way.

Fibers and welded wire reinforcement

Fibers are secondary reinforcement. Synthetic microfibers control plastic-shrinkage cracking while the concrete is fresh; they are not structural reinforcement and are not a substitute for rebar except where a fiber system has been specifically designed and approved as structural reinforcement for that application. Dosages in the CSV are exactly as producers publish them: monofilament polypropylene microfiber 0.5–1.0 lb/yd³ (Sika Fibermesh AC data), fibrillated polypropylene 1.5 lb/yd³ (Propex Fibermesh 300), macrosynthetic 3.0–5.0 lb/yd³ (Propex Fibermesh 650 — 3.0 is the producer's specification minimum, 5.0 its stated maximum rate), steel fiber 25–65 lb/yd³ typical (Bekaert published guidance; ACI's FAQ cites 15–20 lb/yd³ minimums for slabs-on-ground). Bekaert's own caveat is recorded in the row: dosage alone is not a performance value — post-crack performance is established by ASTM C1609 beam testing. Steel fiber at typical rates also reduces measured slump 1–3 in. without an equal loss of workability.

Welded wire reinforcement styles are from the Wire Reinforcement Institute's published sectional-area tables, with weights from a published industry stock-style table: 6×6 styles W1.4 through W5.5 and 4×4 styles W1.4 through W4.0, each with wire diameter, steel area per foot of width, and approximate weight per 100 ft². WWR in slabs-on-ground is temperature/shrinkage reinforcement; like fiber, it is not a structural-rebar substitute unless the design says so.

Admixtures (ASTM C494)

One published-effect line per type, from the C494 type definitions as republished in open standards listings: A water-reducing (≥5% water reduction in qualification testing), B retarding, C accelerating, D water-reducing + retarding, E water-reducing + accelerating, F high-range water-reducing (≥12%; the high-slump effect is temporary, roughly 30–60 minutes per the standard's Note 1), G high-range + retarding, S specific performance. Air-entraining admixtures are not C494 — they are ASTM C260, and the Type S row says so.

What stayed blank, and why

Blank	Why
Ec and fr, all rows	No published per-strength table found in open NRMCA/PCA/DOT/extension sources; ACI gives equations only, and formula outputs are not recorded as data
w/c at 2,500 / 3,500 / 4,500 psi	ACI 211.1 table is published in 1,000-psi steps; no interpolation
w/c at 8,000 psi	Outside the table's published range (ends at 6,000 psi)
Cement content at 2,500 / 5,000 / 6,000 / 8,000 psi	No published typicals found in the scoped sources
Mix proportions at 2,500 / 5,000 / 6,000 / 8,000 psi	Same — producer tickets found only for 3,000–4,500 psi
Slump/air/exposure numbers outside their tables	Sources publish these by element type, aggregate size, and exposure class only — there is no per-strength-class version to record

Legal basis

Every value is a published fact transcribed into our own table with its source named in the row — NRMCA guidance articles and CIP sheets, producer data sheets and batch tickets (Sika, Propex, Bekaert, Day's Concrete Floors), the Wire Reinforcement Institute, a state DOT specification table, and industry republications of ACI table values. No standards document (ACI, ASTM) was copied; where a standard's table values appear, they come through an openly published republication and are cited as such. Facts are not copyrightable; the compilation, framing, and notes are ours.