Economy & Market

Boosting Concrete Workability with Grinding Aids

Published

11 months ago

June 16, 2025

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Dr SB Hegde highlights how AdoCem® WE++ grinding aid improves cement fineness and reduces water demand, effectively minimising slump loss and enhancing concrete workability retention. The study confirms its role in improving both slump retention and compressive strength over time.

In the production of concrete, maintaining consistent workability is crucial for efficient mixing, transporting, and placing of the material. However, concrete slump loss, or the reduction in workability over time, is a common challenge, particularly in large-scale projects where the concrete mix needs to remain workable for extended periods, such as during long-distance transportation or complex placements. Slump loss greater than 150 mm within 3 hours can lead to difficulties in handling and finishing, impacting both the quality and the efficiency of construction.
One effective solution to control slump loss is the use of grinding aids during the cement production process. This technical note focuses on the application of AdoCem® WE++ grinding aid during the cement grinding of Ordinary Portland Cement (OPC) to resolve slump loss issues and improve concrete workability retention.

The role of AdoCem® WE++ grinding aid
AdoCem® WE++ is a high-performance grinding aid designed to improve the efficiency of cement grinding by reducing the energy required to achieve a desired fineness. It works by modifying the surface properties of cement particles, reducing agglomeration, and improving the flowability of the material. As a result, it enhances the production process, reduces specific energy consumption, and improves the overall quality of the cement.
In addition to its primary function in cement grinding, AdoCem® WE++ has been shown to have beneficial effects on the physical properties of the cement, particularly in terms of workability and water demand in concrete mixes. By optimising the cement particle size distribution, the grinding aid can reduce water requirements, resulting in better workability retention and lower slump loss over time.

Slump loss problem in concrete
Concrete slump loss is a significant issue
that affects the workability of fresh concrete. Over time, fresh concrete tends to lose its fluidity, which can lead to challenges in handling and placing the mix. The rate of slump loss is influenced by several factors, including:

Cement fineness: Finer cement particles tend to absorb more water, requiring higher water-to-cement ratios to maintain a constant slump. This leads to increased slump loss.
Cement composition: The chemical composition and particle size distribution of the cement affect hydration rates and, consequently, the workability over time.
Environmental conditions: Temperature, humidity, and mixing conditions also play a critical role in slump retention.

In this context, the introduction of AdoCem® WE++ grinding aid helps optimise cement properties, ensuring that the water demand is minimised and workability is better maintained over an extended period, thereby mitigating slump loss.

Research methodology 4.1 Materials

Cement: Ordinary Portland Cement (OPC) was used in this study.
Grinding aid: AdoCem® WE++ was used as the grinding aid, added at dosages of 0.06 per cent, 0.08 per cent, and 0.10 per cent by weight of cement.
Concrete mix: A standard concrete mix with a water-to-cement ratio of 0.50 was prepared. The target slump was 150 mm, with slump loss measurements taken at intervals up to 3 hours.

4.2 Experimental setup

Cement grinding: OPC was ground in a ball mill, with the addition of AdoCem® WE++ at the specified dosages. The energy consumption, fineness, and particle size distribution of the cement were analysed.
Concrete mix preparation: Concrete was mixed using cement treated with AdoCem® WE++ grinding aid, along with conventional mixing procedures.
Slump testing: Slump was measured using the standard slump cone test at 0, 30, 60, 90, and 180 minutes after mixing to determine the rate of slump loss.
Compressive strength: Concrete cubes (150 mm x 150 mm) were cast, cured, and tested at 7, 28, and 90 days to assess the impact of grinding aids on strength development.

Results and discussion
5.1 Cement fineness and energy consumption
The use of AdoCem® WE++ significantly improved the grinding efficiency, resulting in a more uniform particle size distribution. The cement treated with AdoCem® WE++ showed a Blaine fineness of 320 m²/kg, compared to 300 m²/kg for the control cement, indicating that the grinding aid allowed for finer grinding without increasing energy consumption. This reduced the production costs while improving cement quality.

5.2 Slump retention
The main focus of this study was to evaluate the effect of AdoCem® WE++ on slump retention. Concrete mixes with grinding aid-treated cement showed a notable improvement in slump retention over time compared to the control mix.

Control cement (no grinding aid): The control mix experienced a slump loss of 80 mm after
2 hours.
AdoCem® WE++ at 0.06 per cent dosage: Concrete with cement treated with 0.06 per cent AdoCem® WE++ showed a slump loss of 100 mm after 3 hours, a significant improvement over the control mix.
AdoCem® WE++ at 0.08 per cent dosage: At a dosage of 0.08 per cent, the slump loss was reduced to 120 mm after 3 hours, demonstrating further improvement.
AdoCem® WE++ at 0.10 per cent dosage: The highest dosage of AdoCem® WE++ resulted in the best performance, with only a 150 mm slump loss after 3 hours, which meets the target of maintaining workability over extended periods.

5.3 Hydration behaviour and setting time
The addition of AdoCem® WE++ appeared to slightly delay the initial setting time compared to the control mix. This delay in setting time helps to extend the period during which the concrete remains workable, thereby reducing the risk of excessive slump loss. The improved hydration behaviour
also contributed to better overall consistency in the concrete mix.

5.4 Compressive strength
Concrete cubes made with cement treated by AdoCem® WE++ exhibited slightly higher compressive strength compared to the control mix. At 28 days, the compressive strength of the AdoCem® WE++ mixes were 5 per cent to 8 per cent higher, indicating that the grinding aid not only improved workability but also contributed to more efficient cement hydration and stronger concrete.

Conclusion
The addition of AdoCem® WE++ grinding aid during the cement grinding process significantly improves the workability retention of concrete, effectively maintaining slump loss over a 3-hour period. By optimising the particle size distribution of cement, AdoCem® WE++ reduces water demand and enhances the stability of the concrete mix, thereby ensuring that the slump remains within the desired range (150 mm) for an extended period. Furthermore, the grinding aid improves cement efficiency, reduces energy consumption during grinding, and enhances the strength development of concrete.
This study demonstrates that AdoCem® WE++ is an effective solution for mitigating concrete slump loss, making it a valuable tool for construction projects where concrete workability must be maintained over longer periods. The optimal dosage of AdoCem® WE++ for achieving the best performance in terms of slump retention and strength is around 0.1 per cent by weight of cement.

About the author:
Dr SB Hegde, a global cement industry leader with over 30 years of experience, is a Professor at Jain College of Engineering, India, and a Visiting Professor at Pennsylvania State University, USA.

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TSR Will Define Which Cement Companies Win India’s Net-Zero Race

Published

3 days ago

April 27, 2026

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Jignesh Kundaria, Director and CEO, Fornnax Technology

India is simultaneously grappling with two crises: a mounting waste emergency and an urgent need to decarbonise its most carbon-intensive industries. The cement sector, the second-largest in the world and the backbone of the nation’s infrastructure ambitions, sits at the centre of both. It consumes enormous quantities of fossil fuel, and it has the technical capacity to consume something else entirely: the waste our cities cannot get rid of.

According to CPCB and NITI Aayog projections, India generates approximately 62.4 million tonnes of municipal solid waste annually, with that figure expected to reach 165 million tonnes by 2030. Much of this waste is energy-rich and non-recyclable. At the same time, cement kilns operate at material temperatures of approximately 1,450 degrees Celsius, with gas temperatures reaching 2,000 degrees. This high-temperature environment is ideal for co-processing, ensuring the complete thermal destruction of organic compounds without generating toxic residues. The physics are in our favour. The infrastructure is not.

Pre-processing is not the support act for co-processing. It is the main event. Get the particle size wrong, get the moisture wrong, get the calorific value wrong and your kiln thermal stability will suffer the consequences.

The Regulatory Push Is Real

The Solid Waste Management (SWM) Rules 2026 mandate that cement plants progressively replace solid fossil fuels with Refuse-Derived Fuel (RDF), starting at a 5 per cent baseline and scaling to 15 per cent within six years. NITI Aayog’s 2026 Roadmap for Cement Sector Decarbonisation targets 20 to 25 per cent Thermal Substitution Rate (TSR) by 2030. Beyond compliance, every tonne of coal replaced by RDF generates measurable carbon reductions which is monetisable under India’s emerging Carbon Credit Trading Scheme (CCTS). TSR is no longer a sustainability metric. It is a financial lever.

Yet our own field assessments across multiple Indian cement plants reveal a sobering reality: the primary barrier to scaling AFR adoption is not waste availability. It is the fragmented and under-engineered pre-processing ecosystem that sits between the waste and the kiln.

Why Indian Waste Is a Different Engineering Problem

Indian municipal solid waste is not the material that imported shredding equipment was designed for. Our waste streams frequently exceed 40 per cent to 50 per cent moisture content, particularly during monsoon cycles, saturated with abrasive inerts including sand, glass, and stone. Plants relying on imported OEM equipment face months of downtime awaiting proprietary spare parts. Machines built for segregated, low-moisture waste fail quickly and disrupt the entire pre-processing operation in Indian conditions.

The two most common failures we observe are what I call the biting teeth problem and the chewing teeth problem. Plants relying solely on a primary shredder reduce bulk waste to large fractions, but the output remains too coarse for stable kiln combustion. Others attempt to use a secondary shredder as a standalone unit without a primary stage to pre-size the feed, leading to catastrophic mechanical failure. When both stages are present but mismatched in throughput capacity, the system becomes a bottleneck. Achieving the 40 to 70 tonnes per hour required for meaningful coal displacement demands a precisely coordinated two-stage process.

Engineering a Made-in-India Answer

At Fornnax, our response to these challenges is grounded in one principle: Indian waste demands Indian engineering. Our systems are built around feedstock homogeneity, the holy grail of kiln stability. Consistent particle size and predictable calorific value are the foundation of stable kiln combustion. Without them, no TSR target is achievable at scale.

Our SR-MAX2500 Dual Shaft Primary Shredder (Hydraulic Drive) processes raw, baled, or loosely mixed MSW, C&I waste, bulky waste, and plastics, reducing them to approximately 150 mm fractions at throughputs of up to 40 tonnes per hour. The R-MAX 3300 Single Shaft Secondary Shredder (Hydraulic Drive), introduced in 2025, takes that primary output and produces RDF fractions in the 30 to 80 mm range at up to 30 tonnes per hour, specifically optimised for consistent kiln feeding. We have also introduced electric drive configurations under the SR-100 HD series, with capacities between 5 and 40 tonnes per hour, already operational at a leading Indian waste-processing facility.

Looking ahead, Fornnax is expanding its portfolio with the upcoming SR-MAX3600 Hydraulic Drive primary shredder at up to 70 tonnes per hour and the R-MAX2100 Hydraulic drive secondary shredder at up to 20 tonnes per hour, designed specifically for the large-scale throughput that higher TSR ambitions require.

The Investment Case Is Now

The 2070 Net-Zero target is not a distant goal for India’s cement sector. It starts today, with decisions being made on the plant floor.

The SWM Rules 2026 are already in effect, requiring cement plants to replace coal with RDF. Carbon credit markets are opening up, and coal prices are not going to get cheaper. Every tonne of coal a cement plant replaces with waste-derived fuel saves money on one side and generates carbon credit revenue on the other. Pre-processing infrastructure is no longer just a compliance requirement. It is a business investment with a measurable return.

The good news is that nothing is missing. The technology works. The waste is available in every Indian city. The government has provided the policy direction. The only thing standing between where the industry is today and where it needs to be is the commitment to build the right infrastructure.

The cement companies that move now will not just meet the regulations. They will be ahead of every competitor that waits.

About The Author

Jignesh Kundaria is the Director and CEO of Fornnax Technology. Over an experience spanning more than two decades in the recycling industry, he has established himself as one of India’s foremost voices on waste-to-fuel technology and alternative fuel infrastructure.

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