# PCC Admixtures

Admixtures are the ingredients in PCC other than aggregate, portland cement and water. Typically, an admixture is added to alter a specific PCC property such as workability, setting time, strength or durability.

- Canonical URL: https://pavementinteractive.org/reference-desk/design/mix-design/pcc-admixtures/
- Last updated: 2026-11-01
- Review: reviewed by licensed professional engineers on the previous Pavement Interactive site, where reviewers were not recorded by name
- Standards: ASTM C989

Admixtures are the ingredients in PCC other than aggregate, [portland cement](https://pavementinteractive.org/glossary/portland-cement/) and water. Typically, an admixture is added to alter a specific PCC property such as workability, setting time, strength or durability.

**Table 1.**

| Type | Desired Effect | Material |
| --- | --- | --- |
| Accelerators | Accelerate setting and early strength development | Calcium chloride, triethanolamine, sodium thiocyanate, calcium formate, calcium nitrite, calcium nitrate |
| Air detrainers | Decrease air content | Tributyl phosphate, dibutyl phthalate, octyl alcohol, water-insoluble esters of carbonic and boic acid, silicones |
| Air-entraining | Improve durability in environments of freeze-thaw, deicers, sulfate and alkali reactivityImprove workability | Salts of wood resins, lignin, petroleum acids, proteinaceous material or sulfonated hydrocarbonsSome synthetic detergentsFatty and resinous acids and their saltsAlyklbenzene sulfonates |
| Alkali-reactivity reducers | Reduce alkali-reactivity expansion | Pozzolans, blast-furnace slag, salts of lithium and barium, air-entraining agents |
| Bonding | Increase bond strength | Rubber, polyvinyl chloride, polyvinyl acetate, acrylics, butadienestyrene copolymers |
| Corrosion inhibitors | Reduce steel corrosion activity in a chloride environment | Calcium nitrite, sodium nitrite, sodium benzoate, certain phosphates or flurosilicates, fluroaluminates |
| Damp proofing | Retard moisture penetration into dry PCC | Soaps of calcium or ammonium stearate or oleateButyl stearatePetroleum products |
| Cementitious Minerals | Hydraulic propertiesPartial cement replacement | Ground granulated blast-furnace slagNatural cementHydraulic hydrated lime |
| Natural pozzolans | Pozzolonic activityImprove workability, plasticity, sulfate resistanceReduce alkali reactivity, permeability, heat of hydrationPartial cement replacementFiller | Diatomaceous earth, opaline cherts, clays, shales, volcanic tuffs, pumicitesFly ash (classes C and F)Silica fume |
| Inert minerals | Improve workabilityFiller | Marble, dolomite, quartz, granite |
| Permeability reducers | Reduce permeability | Silica fume, fly ash, ground slag, natural pozzolans, water reducers, latex |
| Pumping aids | Improve pumpability | Organic and synthetic polymersOrganic flocculentsOrganic emulsions of paraffin, coal tar, asphalt, acrylicsBentonite and pyrogenic silicasNatural pozzolansFly ashHydrated lime |
| Retarders | Retard setting time | Lignin, borax, sugars, tartaric acid and salts |
| Superplasticizers (high-range water reducers) | Reduce water-cement ratio by a minimum of 12%Increase workability at low water-cement ratios | Sulfonated melamine formaldehyde condensatesSulfonated naphthalene formaldehyde condensatesLignosulfonates |
| Water reducer | Reduce water demand by a minimum of 5% | LignosulfonatesHydroxylated carboxylic acidsCarbohydrates |
| Workability agents | Improve workability | Air-entraining admixturesCementitious materials, natural pozzolans and inert minerals (except silica fume) |