【C1】Early Strength Admixture

C1 Early-Strength Admixture (C1) is a groundbreaking material designed to replace traditional sulphoaluminate cement (SAC) in construction applications. Engineered for rapid hardening, unmatched strength, and sustainability, C1 delivers superior performance while reducing costs and environmental impact.

Why Choose C1 Over Sulphoaluminate Cement?

1.Rapid Hardening & High Strength

• Achieves initial setting in 15 minutes and final setting in 20 minutes, significantly faster than SAC.

• 3-hour compressive strength exceeds 20 MPa, with 28-day strength surpassing 80 MPa—no strength regression.

• Ideal for time-sensitive projects like structural repairs and precast elements.

2.Micro-Expansion & Crack Resistance

• Contains non-crystalline calcium sulfoaluminate, ensuring micro-expansion during hydration to prevent early cracking.

3.Excellent Compatibility with Additives

• Seamlessly integrates with common concrete admixtures, enhancing workability without compromising performance.

4.Eco-Friendly & Sustainable

• Produced at lower temperatures using industrial by-products (e.g., gypsum, high-alumina waste), reducing carbon footprint by 10–20% compared to SAC.

Application Scene

1. Tunneling: 

• Early-strength admixture is widely used in shotcrete construction in tunneling projects. For example, in tunnels under complex geological conditions, such as the Sichuan-Tibet Railway, shotcrete needs to reach high strength quickly in order to provide initial support and prevent deformation and collapse of the surrounding rock.

2. Shotcrete: 

• Research shows that after adding 10% of early-strength admixture, the 3-hour compressive strength of shotcrete can be more than 3MPa, and the 8-hour compressive strength can reach more than 10MPa, meanwhile, the slump loss is small, and the rebound rate is significantly reduced.

Mixed with C1 and P-0 cement mortar fluidity, setting time comparison experiment

• The setting time is shorter for both C1 and SAC alone, but SAC uses more water; moreover, C1 and SAC replace 30% P-O cement equally, and C1 obviously has shorter setting time.

Early Strength Admixture (C1) Application

For the structure of the rapid repair material our team has done experimental test program, the data are as follows:

Structural fast repair in the application: mixed with C1 flow is obviously better, and 30min flow loss is smaller, 2 hours strength is high, 2 hours mixed with C1 structural repair material compressive strength of 24MPa, mixed with SAC has no strength; 28 days mixed with C1 compressive strength is 30% higher than mixed with SAC.

Technical features

1. Rapid Strength Development

•  Early Strength Admixtures allow shotcrete to reach higher strengths in a short period of time, e.g. 15 MPa or more in 8 hours.

2. Reduced rebound rate: 

• By enhancing the cohesion and bonding of concrete, it reduces the rebound rate of shotcrete and improves the material utilization rate.

3. Strong adaptability

•  It is suitable for a variety of complex engineering environments, such as tunnels, slope support and so on.

4. Special environment construction

• In the special environment such as weak surrounding rock, high heat, water-rich, etc., the early-strength admixture can significantly improve the early strength and durability of the concrete and adapt to the complex construction conditions.

5.Improvement of durability

•  Early-strength admixtures not only improve the early strength, but also enhance the durability of concrete by lowering the electrical flux (reducing the electrolyte transport within the concrete).

Product Characteristics

1.  Fast hardness, high strength, no downsizing

• It contains a large number of amorphous highly active substances that can promote rapid hydration of cement, improve early strength, and can make the hydration reaction more complete, improve the late strength. The strength is not shrinking, and the surface is not powdery.

2. Micro-expansion, anti-cracking

• This product contains amorphous anhydrous calcium sulfoaluminate, etc., which has micro-expansion characteristics during hydration, and can inhibit the early cracking of mixed soil (mortar) with excellent performance.

3. Good adaptability of additives

• This product introduces the group with better adaptability to cementitious materials, and C1 has good adaptability to common admixtures in the market after a large number of experiments.

4. Green environmental protection

• This product and the traditional fast-hardening materials than the firing temperature is low, and mixed with by-products of stone have, high aluminum and calcium industrial solid waste, to achieve the development goal of green low-carbon waste utilization.