Polycarboxylates are a family of polymers with a carboxylate backbone. In concrete, polycarboxylate ether superplasticizers (PCE) have long polyethylene oxide side chains on that backbone. They are the most powerful class of water reducers in use today.
How PCE Works
- The carboxylate backbone adsorbs on cement particles.
- The long side chains stick out into the water and physically keep particles apart (steric hindrance).
- Because the effect does not rely on charge alone, PCE works at low dosage and gives high water reduction.
PCE Family Types
| Type | Designed for |
|---|---|
| Water-reducing type | Maximum water reduction and early strength |
| Slump-retaining type | Long workability during transport |
| Blends | A mix of two or more PCEs for both early strength and slump life |
Our PCE Powder
| Parameter | Typical value (GAC-PCE TDS) |
|---|---|
| Appearance | White or yellowish powder |
| Solid content | 98 ± 0.5% |
| pH (23 °C) | 7 – 10 |
| Na2SO4 | 3.0% max |
| Water content | 3.0% max |
| Loss on ignition | 86% min |
| Chloride ion | 0.1% max |
| Bulk density | 500 – 700 kg/m³ |
| Water reducing rate | 25% min |
It is synthesised from a modified polyether (SAE-IPEG) and is free of calcium chloride, nitrates and nitrites (TDS). Full product details: PCE powder product page.
Practical Notes
- Do not combine PCE with naphthalene (PNS) superplasticizers in the same mix (TDS warning).
- Clay in aggregates can absorb PCE; test with your actual aggregates.
- PCE can change air content; check and adjust air-entraining admixtures.
Mix-Design Considerations
| Factor | Why it matters with PCE |
|---|---|
| Cement type and fineness | Changes how much PCE adsorbs and the dose needed |
| Clay in sand | Clay absorbs PCE side chains and reduces performance |
| Supplementary materials (fly ash, slag, silica fume) | Change water demand and dose |
| Temperature | Affects slump retention |
| Water-cement ratio | PCE is used where very low ratios are needed |
Dosage
The PCE TDS does not give a fixed dosage. Set the dose by trial mixes with your cement, aggregates and target slump, and state it on a clear basis (powder by weight of cementitious material).
Packing and Storage
- PE-lined plastic woven bags, 25 kg.
- Store in a cool, dry, well-ventilated area, protected from moisture.
PCE vs Other Water Reducers
Compared with SNF and lignosulfonate, PCE gives the highest water reduction at the lowest dosage but is more sensitive to cement and clay. See SNF superplasticizer and sodium lignosulfonate.
Frequently Asked Questions
How is PCE dosed?
By trial mixes; the TDS gives no fixed dosage. State it as powder by weight of cementitious material.
What are polycarboxylates?
Polymers with a carboxylate backbone; in concrete, PCE superplasticizers with polyethylene oxide side chains.
What is a PCE-based superplasticizer?
A high-range water reducer that disperses cement by steric hindrance from its side chains.
Is PCE better than SNF?
PCE gives higher water reduction at lower dosage, while SNF is less sensitive to cement and clay. The choice depends on the mix.
What is the water reducing rate of our PCE?
25% min (TDS).