Introduction to water reducers and representative products

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There’s no information on this topic in the forum. I’ve gathered materials from online sources; some tables couldn’t be included because the text-editing functions in the forum aren’t suitable for them. :Q Water-reducing admixtures fall under the categories of water treatment and plasticizers. A water-reducing admixture is a substance that allows for a reduction in the amount of water used in mixing, while maintaining the workability of concrete and the amount of cement used, thereby increasing the strength of the concrete； Or admixtures that reduce the amount of cement used while maintaining workability and strength. 　　Based on their water-reducing and strengthening capabilities, they are divided into ordinary water reducers (also known as plasticizers) and high-efficiency water reducers (also known as superplasticizers), which are further classified into first-class products and qualified products. 　　Classified by constituent materials: (1) Alkyl sulfonates ； (2) Polycyclic aromatic salts ； (3) Water-soluble resin sulfonates. 　　Conventional water reducers are suitable for concrete work carried out when the daily minimum temperature is above 5°C. High-efficiency water reducers are suitable for concrete work carried out when the daily minimum temperature is above 0°C, and they are applicable to the production of highly fluid concrete, high-strength concrete, as well as autoclaved concrete. 　　The commonly used water-reducing agents in the market currently include: naphthalene-based high-efficiency water-reducing agents, aliphatic high-efficiency water-reducing agents, amino super-high-performance water-reducing agents, water-reducing accelerators, sodium saccharinate, sodium lignosulfonate, lignosulfonic acid, and expansion agents. Mechanism of action of water-reducing agent in waterproof concrete: Water-reducing agent waterproof concrete is prepared by adding an appropriate amount of water-reducing agent to concrete, with the aim of improving its impermeability; it is now widely used. The water reducers used in the preparation of waterproof concrete mainly include calcium lignosulfonate water reducers, polycyclic aromatic sulfonate sodium water reducers, and sugar-melasse retarding water reducers. Calcium lignosulfonate superplasticizer is also known as M-type superplasticizer, sugar-density retarding superplasticizer, etc. Calcium lignosulfonate superplasticizer is also known as type M superplasticizer, while polycyclic aromatic sulfonate sodium salts superplasticizers come in various types such as MF, JN, NNO, FDN, and UNF. During the hydration process of ordinary concrete, the mineral composition of cement carries opposite charges that cause attraction between particles; the thermal movement of these cement particles in the liquid phase leads to collisions and adhesion between them, and there is also a cohesive force acting between the particles. All these factors result in the formation of irregular flocculent structures among the cement particles, which contain a large amount of mixing water. This reduces the surface area of contact between the cement particles and water, preventing thorough hydration of the cement and thereby lowering the density of the concrete ； At the same time, the flocculent structure increases the friction between cement particles, which reduces the workability of the concrete mixture. To achieve the desired workability, more water must be used in mixing, resulting in excess water remaining during the curing process. When this excess water evaporates, pores are formed, which is detrimental to waterproofing and impermeability. Water reducers are surface-active substances; when added to fresh concrete, their adsorption-and-diffusion mechanism breaks down the flocculent structure of the cement, releasing the water that was previously trapped within it. This allows for a reduction in the amount of water used in mixing, while still maintaining the desired workability. As a result, the amount of free water in the concrete is reduced, and the capillary pores formed due to water evaporation are diminished, thereby improving the density of the concrete. At the same time, the anions generated when the water-reducing agent dissolves in water adsorb onto the surface of the cement particles, causing them to carry a negative charge and repel each other; this separates the cement particles from one another, resulting in a highly uniformly dispersed suspension of particles. As a consequence, the distribution of pore structures in the concrete is improved, with both the pore size and the overall porosity being significantly reduced. When air-entraining water reducers such as type M and type MF are incorporated, in addition to the aforementioned water-reducing mechanism, they also generate fine and uniform closed bubbles within the concrete, thereby reducing bleeding and enhancing the concrete’s impermeability. Water reducers, especially those with retarding effects, can also delay the onset of the peak heat generation during cement hydration. This allows the concrete to possess a certain tensile strength by the time cooling begins after the peak heat period, enabling it to resist thermal stresses; as a result, cracks can be reduced or prevented, and the concrete’s impermeability can be improved as well. 　 TH-928 Polycarboxylate-based high-performance water reducer (OPQC series water reducers) TH-928, a polycarboxylate-based high-performance water reducer, is currently the most advanced type of concrete superplasticizer (water reducer) in the world, featuring the highest level of technological sophistication, the best prospects for application, and the optimal overall performance. TH-928 is a high-performance polycarboxylate superplasticizer, which is a composite product of carboxylic acid-grafted polymeric copolymers along with other effective additives. Comparisons with similar products at home and abroad have shown that the TH-928 polycarboxylate-based high-performance water reducer meets international advanced standards in terms of technical performance indicators and cost-effectiveness. 　　I. Performance Characteristics 　　1. Low dosage with high water reduction rate; the water reduction rate can reach up to 45% ； 　　2. When the slump is low, the loss is minimal; the slump loss rate for pre-mixed concrete is less than 5% after 1 hour and less than 10% after 2 hours ； 　　3. The enhancement effect is significant: the 3D compressive strength of concrete increases by 50–110%, the 28-day compressive strength increases by 40–80%, and the 90-day compressive strength increases by 30–60% ； 　　4. The concrete has excellent workability, with no segregation or bleeding, and its appearance is uniform in color. When used to prepare high-strength concrete, it provides good cohesion to the concrete and is easy to mix ； 　　5. It has a moderate air content, which has no adverse effect on the elastic modulus of concrete; it also boasts good frost resistance and durability ； 　　6. It can reduce the early hydration heat of cement, which is beneficial for mass concrete and construction in summer ； 　　7. It has excellent adaptability, good compatibility with cement and admixtures, as well as good temperature tolerance; it exhibits good compatibility with various types of cement and admixtures, addressing the issue of poor compatibility between other types of water reducers and cementitious materials ； 　　8. Low shrinkage: it can significantly reduce concrete shrinkage, and its resistance to freeze-thaw cycles and carbonation is markedly superior to that of ordinary concrete ； Significantly improves the volume stability and long-term durability of concrete ； 　　9. The alkali content is extremely low, at ≤0.2%, which effectively prevents the occurrence of alkali-aggregate reaction. 10. The product has good stability; no stratification or precipitation occurs during long-term storage, and no crystallization takes place at low temperatures ； 　　11. The product is eco-friendly and free of formaldehyde, making it an environment-friendly option ； 　　12. It offers good economic benefits; the overall cost of the project is lower compared to using other types of products, and 15–25% less cement can be used under the same strength requirements. 　 II. Technical Specifications
Homogeneity specifications of TH-928 polycarboxylate-based high-performance water reducer

| Parameter | Specification |
|-----------|---------------|
| Appearance | Light brown liquid |
| Density (g/ml) | 1.09±0.02 |
| Solid content (%) | 22±2 |
| Flowability of cement paste (reference cement) (mm) | ≥ 250 (W/C=0.29) |
| pH | 6–8 |
| Chloride content (%) | ≤ 0.02 |
| Alkali content (Na2O + 0.658K2O) (%) | ≤ 0.2 |

III. Instructions for Use
1. The dosage ranges from 0.4% to 2.0% of the total weight of the binding materials; the commonly used dosage is 0.4% to 1.2% ； Concrete mix trials should be conducted prior to use to determine the optimal dosage ； 　　2. It shall not be used in combination with naphthalene-based high-efficiency water reducers; when used together with other admixtures, concrete compatibility tests must be conducted in advance ； 　　3. Slump has a high sensitivity to water content; it is necessary to strictly control the amount of water used during application ； 　　4. Pay attention to the curing of the concrete surface. 　　IV. Scope of Application Applicable to pumped or normal concrete projects with strength grades of C15~C60 and above. It is particularly suitable for concrete projects that require high durability, good flowability, excellent slump retention, high strength, and high standards regarding appearance quality. It is highly advantageous for preparing high-fluidity concrete, self-compacting concrete, and fair-faced concrete. 　　V. Packaging and Storage 　　1. TH-928, a high-performance polycarboxylate-based water reducer, is a liquid product that is supplied in barrels ； 　　2. It should be stored in a cool, dry place, away from direct sunlight, and protected from frost in winter ； 　　3. The sealed storage period is 12 months; it can still be used after expiration provided it passes verification. HSB aliphatic high-efficiency water reducer HSB (High Strence Bing) is a carbonyl pyroglual formed through the synthesis of polymer sulfones. The hydrophobic backbone, which is an aliphatic hydrocarbon and hereafter referred to as HSB, is a green and efficient water-reducing agent developed in Qingdao. This product does not pollute the environment nor harm human health. It has wide applicability in cement, provides a significant enhancement effect on concrete, results in minimal loss of slump, and does not exhibit sodium sulfate crystallization at low temperatures. It is widely used in the formulation of various specialty water reducers such as those for pumping, retarding, early strength, freeze protection, and air entrainment; it can also be used in combination with naphthalene-based water reducers, amino water reducers, and polycarboxylate water reducers. 　　I. Main technical specifications 1. Appearance: brownish-red liquid ； 2. Solid content > 35% ； 3. Specific gravity: 1.15–1.2 II. Performance characteristics: 1. High water reduction rate. With a dosage of 1-2%, the water reduction rate can reach 15-25%. Under the same strength and slump conditions, the use of HSB can reduce cement consumption by 25-30% ； 　　2. It exhibits significant early-strength and reinforcement effects. When HSB is added to concrete, it can reach 60-70% of the designed strength after three days, 100% after seven days, and its strength is 30-40% higher than that of concrete without HSB after 28 days ； 　　3. High plastic retention. The slump loss of concrete is minimal over time; there is almost no loss after 60 minutes, while a loss of 10–20% occurs after 90 minutes ； 　　4. It has wide applicability to cement, with good workability and cohesion. Works well in combination with various other types of admixtures ； 　　5. It can significantly improve the frost-thaw resistance, impermeability, and resistance to sulfate attack of concrete, as well as enhance other physical properties of concrete overall ； 　　6. It is particularly suitable for the following types of concrete: fluidized plasticized concrete, concrete cured naturally or by steaming, waterproof and impermeable concrete, durable concrete resistant to freeze-thaw cycles, marine concrete resistant to sulfate attack, as well as reinforced concrete and prestressed concrete ； 　　7. HSB is non-toxic, non-flammable, does not corrode rebar, and does not produce sodium sulfate crystals in winter. 　　III. Usage Method 　　1. Determine the optimal dosage through experiments; the recommended dosage is 1.5-2% ； 　　2. HSB can be added to the concrete together with the mixing water; an alternative approach is to add it later, in which case mixing time should be extended by 30 seconds for the concrete containing HSB ； 　　3. Due to the high water reduction rate of HSB, a layer of yellow slurry will emerge on the surface before the concrete sets; this is a normal phenomenon. After pouring the concrete and finishing it with a trowel, the color will disappear; or once the concrete has gained strength, the color will fade away on its own. Watering the concrete during curing will accelerate this fading process, without affecting the internal or surface properties of the concrete. 　　IV. Storage and Packaging 　　1. HSB can be stored at temperatures between -20 and 40 degrees Celsius, but it should not be exposed to direct sunlight; its shelf life is one year. 　　2. Packaging: Available in 250KG iron drums or in bulk; packaging can also be arranged according to the customer’s requirements. This post was last edited by zosy990 on 2008-12-22 14:47.]