What Is the Dosage Ratio of Superplasticizer in GRC? Qinglong's Precise GRC Admixture Control Technology

High-range water reducers are a key technology for achieving GRC's low water-cement ratio and high durability, and their dosage directly affects workability and economy. Through systematic research, Qinglong GRC has established a scientific admixture usage system.

In a super high-rise project in Shenzhen, Qinglong GRC used a polycarboxylate-based water reducer; at a dosage of 0.8%, the water reduction rate reached 35%, lowering the water-cement ratio from 0.38 to 0.32 while maintaining the same fluidity. Microstructural analysis showed that the electrostatic repulsion of the water reducer dispersed cement particles more evenly, increasing the release of entrapped water in the flocculated structure by 15%, which is the key to achieving the high water reduction rate. The delayed addition method adopted in the project improved water reducer utilization by 20%, reducing costs while ensuring workability.

Relationship Between Water Reducer Types and Dosage

Naphthalene-based water reducers: 0.5%-0.8%, water reduction rate 15%-20%; aminosulfonate-based: 0.6%-1.0%, water reduction rate 25%-30%; polycarboxylate-based: 0.8%-1.2%, water reduction rate 30%-40%. Different water reducers suit different cement types, and the optimal dosage must be determined through testing.

Effect of Dosage on Performance

For every 0.1% increase in dosage, the water reduction rate rises by 3%-5%, but overdosing causes bleeding and segregation. Within the optimal dosage range, compressive strength increases with dosage; beyond the critical value, strength growth levels off. Shrinkage first decreases and then increases with dosage, with an optimal value.

Corrections for Construction Environment Effects

For every 10℃ rise in temperature, the water reducer dosage must be adjusted by 0.1%-0.2%. When humidity is below 60%, the dosage should be appropriately reduced by 0.1%. For long-distance transport, use sustained-release water reducers with the dosage increased by 0.2%-0.3%.

Quality Control and Acceptance Criteria

Each batch of water reducer must undergo a cement paste fluidity test upon arrival; batches with deviation exceeding 10% are rejected. During production, dosage error is controlled within ±0.05%. The solid content of the water reducer is tested regularly, and the dosage adjusted promptly.

Water reducer usage requires precise control. Through automatic metering systems and online monitoring, Qinglong GRC ensures accurate and stable dosage, safeguarding GRC's high performance.