Powder Water Reducing Agent

A water-reducing agent, also known as an admixture or plasticizer, is a chemical additive used in concrete and cement mixtures to reduce the water content needed for workability without sacrificing strength. By decreasing the water-cement ratio, these agents help improve the concrete’s compressive strength, durability, and overall performance.

Types of Water-Reducing Agents

1. Normal Water Reducers: Reduce water content by about 5-10%. They are commonly used in general concrete mixes.
2. High-Range Water Reducers (Superplasticizers): Reduce water content by more than 25-45%. They enable the production of highly flowable concrete with minimal water, suitable for intricate work or high-strength applications.
3. Retarding or Accelerating Agents: Some admixtures also modify setting times, but their primary function relates to controlling the hydration process.

Common Chemical Types

• Lignosulfonates
• Melamine Superplasticizer
• Polycarboxylate Superplasticizer
• Napthalene sulfonates

 Specifications

The powdered polycarboxylate superplasticiser presents as a white powder and functions as a high-performance superplasticiser/water-reducing agent, combining high water-reduction rates with excellent workability retention. This versatile powdered polycarboxylate superplasticiser can be flexibly applied in mortars formulated with various cementitious and gypsum-based binder systems. By employing powdered polycarboxylate superplasticisers, mortar products achieve significantly enhanced workability and flow properties, thereby effectively elevating the overall quality of both cementitious and gypsum-based materials. Furthermore, this superplasticiser demonstrates excellent compatibility, permitting concurrent use with other mortar additives such as early-strength agents, retarders, redispersible polymer powders, and defoamers without adversely affecting other mortar properties.

Naphthalene-based high-efficiency water-reducing agents appear as brown powders. They exhibit outstanding water-reducing properties; when an appropriate amount is incorporated into concrete, they can significantly reduce the required water content, achieving a water-reduction rate of 15%-20%. Additionally, they possess a degree of slump retention, typically employed in the production of C30 concrete.

The issue of sodium sulphate generated during the production of naphthalene-based high-efficiency water-reducing agents warrants attention. Following filtration, the sodium sulphate content in high-efficiency agents is controlled below 5%, whereas standard types may contain up to 20%. It is noteworthy that while sodium sulphate contributes to early strength development, the sodium ions it contains adversely affect concrete durability. Furthermore, naphthalene-based high-performance water-reducing agents require industrial naphthalene, sulphuric acid, and formaldehyde as raw materials, which cause environmental pollution. Additionally, their compatibility with cement requires improvement. Simultaneously, concrete produced using naphthalene-based water-reducing agents exhibits significant shrinkage, making it prone to cracking.

Lignosulfonate water-reducing agents are conventional water-reducing admixtures classified as anionic surfactants. They may be employed directly or serve as a component in compound admixtures. Due to their cost-effectiveness, they remain widely utilised. When incorporated into mortar, they enhance workability and flowability while increasing strength, with a water-reduction rate of 8%–10%.

Lignosulphonates are categorised into calcium lignosulphonate and sodium lignosulphonate based on production processes: both may be employed as concrete water-reducing agents, though they exhibit relatively high air-entraining properties. Presently, standalone lignosulphonate-based water-reducing agents are seldom utilised in the market, being almost exclusively blended with high-efficiency water-reducing agents.