Kraft Vapor Curing Technology for Eco Stone Precast Infra.

India has emerged as one of the most dynamic and strategically important markets for Kraft Curing Systems. With the country’s rapid urbanization, ambitious infrastructure investments, and growing demand for high-quality building materials, India’s concrete industry is expanding at a remarkable pace. In response, Kraft Curing has significantly increased its local footprint: more than 50 curing systems have been installed across the country, backed by three full-time service technicians, as well as a dedicated sales manager based locally.

This strong presence is no coincidence—India’s construction sector is one of the fastest-growing in the world, with billions being invested in housing, commercial development, smart cities, and transportation infrastructure. The need for faster, more reliable, and higher-quality concrete products has never been greater. And that’s exactly where Kraft’s curing technology excels.

One standout example of this successful expansion is the partnership with Eco Stone Precast Infra., a forward-thinking precast concrete and concrete block manufacturer based in Rajasthan. With a focus on quality, efficiency, and future-ready production methods, Eco Stone turned to Kraft Curing Systems to modernize and optimize their concrete curing process. The result is a custom-engineered vapor curing system that has not only accelerated their concrete block production, but also dramatically improved the consistency and durability of their product.

Vapor Curing: A Game Changer for Concrete Block Production

At the heart of the project is Kraft’s KC 10-1S direct-fired Vapor Generator, a 300 kWh, non-IBR system capable of delivering vapor instantly and precisely. This system introduces controlled heat and humidity into the curing environment, accelerating strength gain in concrete blocks while enhancing their durability and appearance. The impact on production has been substantial: blocks can now be dispatched the day after casting, thanks to significantly shortened curing times and consistent temperature and humidity profiles. With temperatures up to 50 °C and relative humidity reaching 99%, Eco Stone is achieving faster curing without sacrificing product integrity.

As a result, their blocks now feature:

Harder edges and corners;

Reduced breakage during handling and shipping;

Significant reduction in efflorescence;

More consistent surface color.

Customized Chambers and Local Integration

The system’s design includes five independent curing zones, all housed within customer-supplied chambers, constructed according to Kraft’s detailed engineering drawings and specifications. These curing zones are sized at 15 x 4.5 x 3.6 meters, each capable of curing up to 30,750 kg of concrete per cycle, with total daily throughput exceeding 154,000 kg. With a chamber fill time of just 2 to 3 hours, Eco Stone’s production flow has become significantly more efficient.

Importantly, by locally sourcing and fabricating the curing chambers and vapor distribution piping based on Kraft’s detailed layout and bill of materials, Eco Stone managed to reduce capital costs and minimize dependency on imported equipment, all without compromising system performance.

Precision-Controlled Curing Process

The Kraft vapor curing system operates through a fully automated, multi-phase process that is precisely managed by the AutoCure control system, ensuring optimal curing conditions in every zone. The process begins with the Preset phase, during which the freshly cast concrete is allowed to rest for approximately one hour.

Following this, the system transitions into the Ramp phase, where the temperature within the curing chamber is gradually increased. The rise is carefully controlled, typically at a rate of about 10 Kelvin per hour, over a period of two to three hours. This slow, measured increase prevents thermal shock and supports uniform internal development within the concrete blocks.

Once the target curing temperature is reached – up to 50°C, with relative humidity levels approaching 99% – the process enters the Soak phase. Lasting six to nine hours, this is the most critical stage of the cycle. The concrete is maintained under these stable high-temperature, high-humidity conditions, allowing it to fully hydrate and gain the desired early strength. This consistent environment contributes to a significant reduction in surface defects, minimizes the risk of efflorescence, and ensures uniform color and hardness throughout the block.

The entire process is supported by a network of stainless-steel vapor valves, temperature and humidity sensors, and motorized control systems, all working together to deliver precise, repeatable, and energy-efficient curing. This level of control ensures that each batch of concrete blocks achieves consistent quality, durability, and strength, meeting the rigorous demands of modern concrete production.

Efficiency and Sustainability Built In

Compared to conventional steam boilers, Kraft’s vapor generator offers 60% lower operating costs, thanks to ist direct-fired combustion design. The system operates at low pressure, runs on natural gas or propane, and requires minimal floor space, making it ideal for facilities focused on energy efficiency and safety.

Key technical features include:

98% operating efficiency;

Water-cooled 304L stainless steel combustion chamber with lifetime warranty;

Fully automatic, low-maintenance operation;

Safe, insulated vapor piping and chamber construction;

Flexible curing temperatures from 35 °C to 80 °C.

Eco Stone also benefits from detailed technical support, including stamped structural drawings available on request for compliance with wind, snow, or seismic load standards.

Concrete Results from a Global Partnership

The partnership between Kraft Curing Systems and Eco Stone Precast Infra. is more than a one-off equipment installation, it’s a compelling example of how international engineering expertise and localized execution can drive measurable improvements in concrete manufacturing. At its core, this project demonstrates how tailored concrete curing technology – designed in Germany, applied in India - can bridge performance gaps and unlock new levels of production capacity and product quality. By collaborating closely during the design, engineering, and installation phases, both companies ensured that the system would not only meet the unique environmental and operational conditions in Rajasthan but also support Eco Stone’s long-term growth strategy.

With the new vapor curing system in place, Eco Stone now benefits from:

Faster production cycles, allowing blocks to be shipped the day after casting;

Superior product quality, with stronger edges and fewer defects;

Lower operating costs, with up to 60% savings on energy compared to traditional steam curing;

Reduced maintenance, thanks to the system’s robust design;

Greater sustainability, through efficient fuel use, local material sourcing, and minimal waste.

Additionally, the decision to locally fabricate the curing chambers and vapor distribution piping, under Kraft’s guidance, helped Eco Stone reduce lead times, optimize project budgets, and develop in-house technical capability. This localization approach aligns with global sustainability and economic resilience goals.

For Kraft, the success at Eco Stone reinforces its reputation as a global leader in concrete curing technology, with the ability to custom-engineer solutions for manufacturers anywhere in the world. Whether working in Europe, North America, or South Asia, Kraft’s team combines precise design, high-performance equipment, and on-site engineering support to deliver results that stand the test of time—and temperature.