Magnesium lignosulfonate for concrete is used as a normal-range water reducer and plasticizer. This page is a selection and dosing guide for concrete producers and admixture blenders: which grade to use, where to start, and what to test.
Which Grade for Concrete?
| Grade | Why use it | Notes |
|---|---|---|
| Grade One (GAC-MgLS-1) | Low insolubles (1.0% max), pH 4 – 7 | First choice for admixture blending |
| Liquid (GAC-MgLS-L) | Pumped dosing, about 45% solids | Count the water it carries |
| Grade Two (GAC-MgLS-2) | Alkaline (pH around 10) | Check compatibility first |
Starting Dosage and Trial Plan
| Mix | Dry dose (% of cement) | Measure |
|---|---|---|
| Control | 0 | Slump, air, setting time, strength |
| Low | 0.20% | Same |
| Mid | 0.25% | Same |
| High | 0.30% | Same |
What to Expect
- A normal-range water reducer under ASTM C494 Type A, or Type D where it also retards setting; both must cut water to no more than 95% of a control mix.
- Some set retardation, more at higher dose.
- Possible air entrainment; measure air content.
- Any strength gain comes from the lower water-cement ratio; measure it rather than assume a figure.
Blending With Other Admixtures
Lignosulfonates are often blended with naphthalene (SNF) or polycarboxylate (PCE) superplasticizers to balance cost, slump retention and setting. Check the blend for stability and the concrete for slump loss before production.
Grade Data
| Grade (code) | Form | Lignosulphonate (dry basis) | pH | Other key values |
|---|---|---|---|---|
| Grade One (GAC-MgLS-1) | Yellow-brown powder | 55% min | 4 – 7 | Total Mg + Ca 8% min; insolubles 1.0% max; reducing matter 7% min |
| Grade Two (GAC-MgLS-2) | Powder | 50% min | around 10 | Total Mg + Ca 5% min; insolubles 1.5% max |
| Liquid (GAC-MgLS-L) | Liquid, about 45% solids | 50% min | — | Insolubles 1% max; reducing sugar about 7% |
| Feed Grade (GAC-MgLS-Feed) | Light to dark brown powder | 55% min | 4.5 – 6.5 | Pb 10, As 3, Cd 1 mg/kg max; Salmonella negative in 25 g |
Product and documents: magnesium lignosulfonate product page. Mechanism: magnesium lignosulfonate in concrete.
Packing and Storage
- Powder: 25 kg lined woven bags or 500 – 600 kg jumbo bags; 24 months unopened; keep dry and reseal opened bags.
- Liquid: flexitank, IBC or drums; 12 months; protect from freezing.
- Keep away from strong oxidizers, acids and bases (SDS).
Compared With Other Water Reducers
| Type | Water reduction class | Setting | Typical use |
|---|---|---|---|
| Lignosulfonates (Ca, Na, Mg) | Normal range (ASTM C494 Type A/D) | Retard, more at high dose | Ready-mix, precast, blends |
| Naphthalene (SNF) | High range (Type F) | Little effect at normal dose | High-strength concrete |
| Polycarboxylate (PCE) | High range (Type F) | Depends on design | Self-compacting, high-performance concrete |
Frequently Asked Questions
What is the dosage of magnesium lignosulfonate in concrete?
Start at 0.20 – 0.30% dry by weight of cement and adjust by trial; the liquid needs about 2.2 times that weight.
Which magnesium lignosulfonate grade is used in concrete?
Grade One for most admixture work; the liquid where you dose by pump.
How much water does magnesium lignosulfonate reduce in concrete?
It is a normal-range water reducer. Our magnesium TDS gives no fixed figure, so measure water reduction in your own trial mixes.
Can magnesium lignosulfonate be used in precast concrete?
Yes, as a normal-range water reducer; check setting time because early strength matters in precast.
