Concrete

Making Concrete in Cold Conditions

Published

9 years ago

February 28, 2017

admin

Cold weather is defined as a period when the average daily temperature falls below 4?C for more than three successive days. These conditions warrant special precautions when placing, finishing, curing and protecting concrete.

Concrete production always faces a problem during cold weather. There are two main problems associated with cold weather. The general rule is that the concrete has to gain strength till about 500 psi (35 kg per cm2).

Concrete can freeze before it gains strength which breaks up the matrix;
Concrete sets more slowly when it is cold – very slow below 6? C; below 4? C, the hydration reaction basically stops and the concrete doesn’t gain strength.
But these are concrete temperatures, not air temperatures. So when it’s cold, the concrete has to be protected until it can handle the cold on its own. The general rule is that the concrete has to gain strength till about 500 psi (35 kg per cm2). Almost the same time that the concrete achieves 500 psi compressive strength, hydration of the cement consumes enough of the water in the original mix so that even if it does freeze, there’s not enough water left in the pores to damage the concrete. With most concrete, even at 6?C, this happens during the second day.

To help it reach that 500 psi strength, the mix can then be changed to get it to set more quickly or protect the concrete from the cold – or more likely do both.

Changes to Concrete Mix during Cold Weather
Many of the problems with cold weather can be overcome by the ready mix producer. Here are a few things to keep in mind:
Hot water: A ready mixed concrete producer will usually have, and use, hot water in the concrete when the weather turns cold. Most producers will try to have the concrete be at least 180C when it leaves the plant, which is generally good enough depending on air temperature and thickness of the concrete element. The slump has to be specified at less than 100 mm and air-entrained concrete should be used to reduce bleeding.

Accelerators: Since colder weather leads to colder concrete, the set time can be delayed. Accelerators added to the concrete can keep it on schedule. Addition of 2 per cent (by weight of cement) of calcium chloride is the traditional way to accelerate the hydration reaction – it is very effective and reasonably cheap. But – a big but -that much chloride can lead to corrosion of any steel embedded in the concrete (like rebar) and can lead to a mottled surface appearance with coloured concrete.

Non-chloride accelerators are also widely available and are very effective. They won’t discolour the concrete, but they are a bit expensive. Accelerators are not anti-freeze agents – they simply increase the rate of the hydration reaction.

Fly ash: Producers should typically stay away from using fly ash or slag cement in cold weather, since those materials set more slowly and generate less internal heat; slag can cause the same effect.

To make the reaction a bit hotter, the ready mix producer can add some extra cement (typically 60 kg per cubic metre) or can use Type III (high-early strength) cement, which hydrates more rapidly.

Producers have to be careful with water reducers in cold weather, since they can slow the set time. Besides, cooler concrete seldom needs water reduction since the cooler temperatures prevent slump loss. For admixtures added at the job site, they shouldn’t be used if they have frozen. The chemicals may have separated.

Precautions before Placing Concrete in the Cold
When cold weather comes on unexpectedly, the following tips will help:
Frozen ground: Concrete should be never placed on frozen ground or onto ice or snow. There are a couple of problems with this. First, frozen ground will settle when it thaws, cracking the concrete. Second, when the ground is cold, the concrete in contact with it will be cold and will set more slowly. Crusting might also occur, with the top part of the concrete set and the bottom still soft. If the ground is frozen, it can be thawed using hydronic heat pipes and blankets (such as those from ground heaters), or electric blankets.

Anything that will come in contact with the concrete should be warmed up, including forms and any embedment, to at least 00C. If it’s not too cold and everything is covered with tarps the day before the pour, it will stay dry and warm enough.

Concrete

Cement Makers Reaffirm Commitment to Sustainable Growth

Published

2 days ago

June 5, 2026

admin

World Environment Day spotlight on innovation and circularity

On World Environment Day, the Indian cement industry reiterated its commitment to supporting India’s climate ambitions through sustainable manufacturing, resource efficiency and the adoption of cleaner technologies.

The Cement Manufacturers’ Association (CMA) said the sector remains aligned with the Government of India’s Net Zero commitments and is accelerating efforts to reduce its environmental footprint while supporting the country’s infrastructure and development agenda.

Parth Jindal, President, CMA and Managing Director, JSW Cement, said the industry is increasingly adopting cleaner technologies, improving energy efficiency and expanding the use of alternative fuels and raw materials. He also highlighted the growing importance of circular economy practices, where industrial by-products and waste streams from one sector are utilised as resources in another.

“The Indian Cement Industry is aligned to the Government’s commitments on carbon mitigation and is accelerating the adoption of cleaner technologies, resource efficiency and circular economy practices while actively exploring the potential of Carbon Capture, Utilisation and Storage (CCUS) as a critical pathway for deep decarbonisation,” said Jindal.

He added that coprocessing industrial waste and by-products helps conserve natural resources, reduce disposal requirements and lower the environmental footprint across multiple sectors.

According to Jindal, sustainability is no longer limited to manufacturing processes but is increasingly influencing investment decisions, innovation strategies and long-term growth plans within the industry.

Echoing similar views, Dr Raghavpat Singhania, Vice President, CMA and Managing Director, JK Cement, said sustainable development extends beyond emissions reduction and must also focus on responsible resource utilisation and waste minimisation.

“Sustainability in the built environment cannot be measured by emissions alone. It is equally about how efficiently we use resources, how effectively we minimise waste and how responsibly we create the infrastructure that will serve future generations,” said Singhania.

He noted that the cement industry is advancing its sustainability agenda through greater resource efficiency, increased circularity, technological innovation and continuous improvements in manufacturing practices. As a key contributor to India’s infrastructure development, the sector has a critical role to play in balancing economic growth with environmental responsibility.

On the occasion of World Environment Day, industry leaders reaffirmed their commitment to supporting India’s climate goals while delivering the materials required for resilient, durable and sustainable infrastructure.

Concrete

Building a Greener Future Together

Published

3 days ago

June 4, 2026

admin

Environmental sustainability requires immediate action, not just long-term commitments and discussions. Recycling, circular economy practices, and technology-driven waste management can help industries reduce environmental impact while supporting sustainable growth.

Author: Jignesh Kundaria, Director and CEO, Fornnax Technology

World Environment Day serves as an important reminder that environmental sustainability can no longer remain confined to discussions, reports, or long-term commitments. The environmental challenges facing the world today demand immediate, measurable, and collective action. Across industries and communities, waste generation continues to outpace our ability to process it responsibly, placing increasing pressure on ecosystems, natural resources, public health, and the well-being of future generations.

One of the most significant shifts required today is a change in how society perceives waste. Rather than being viewed as a material to be discarded, waste must be recognised as a valuable resource that can contribute to both economic growth and environmental protection when managed through the right technologies and systems. This mindset forms the foundation of the circular economy model that countries across the world are increasingly adopting to reduce landfill dependence, recover valuable materials, and create more sustainable industrial ecosystems.

India has made meaningful progress in strengthening awareness around sustainability, recycling, and environmental responsibility over the past decade. Significant efforts are being made to formalise the recycling sector through improved infrastructure, technology adoption, policy implementation, and broader stakeholder participation. These developments are creating a stronger foundation for responsible waste management and resource recovery across the country.

However, achieving long-term environmental impact requires collaboration from all stakeholders. Industries, policymakers, technology providers, and communities must work together with greater accountability to strengthen recycling ecosystems, encourage responsible waste management practices, and create sustainable outcomes through consistent execution rather than temporary interventions.

As someone closely associated with the recycling industry, I firmly believe that technology will play a decisive role in addressing future environmental challenges. Advanced recycling systems have the potential to recover valuable resources, reduce pollution, minimise landfill burdens, and conserve energy, creating a more sustainable future for generations to come. This belief is deeply reflected in Fornnax’s motto, “Committed to Create a Green Future,” which embodies our commitment to building long-term environmental value through innovation and responsible action.

At the same time, technology alone cannot deliver meaningful change. Real progress requires intent, awareness, participation, and a shared sense of responsibility. Sustainable development can only be achieved when innovation is supported by collective action and a genuine commitment to environmental stewardship.

On this World Environment Day, let us move beyond conversations and take meaningful steps towards creating a cleaner, greener, and more sustainable planet. By embracing innovation, strengthening recycling ecosystems, and acting responsibly today, we can create lasting environmental impact and secure a better future for generations to come.

Concrete

JK Lakshmi Advances LC3 Cement Expansion

Company highlights commercial production and research partnerships

Published

6 days ago

June 1, 2026

admin

The meeting reviewed progress in limestone calcined clay cement (LC3) technology and its commercial adoption in India’s cement sector, focusing on low-carbon alternatives to conventional binders. JK Lakshmi Cement noted that limestone calcined clay cement can reduce carbon dioxide emissions by up to 40 per cent compared with conventional cement and said this reduction supports industry decarbonisation. The company highlighted that it was among the first two cement manufacturers in India to move LC3 into commercial production after the Bureau of Indian Standards approved the technology as a cement standard.

Vinita Singhania said the transition of LC3 from research to commercial production reflected collaboration between industry, academia and international institutions. Maya Tissafi acknowledged JK Lakshmi Cement’s role in advancing LC3 adoption in India and its contribution in taking the technology from laboratory trials to commercial implementation. Both representatives underlined the growing relevance of sustainable construction materials as India expands infrastructure and urban development.

The meeting explored continued collaboration with Swiss research institutions such as EPFL, EMPA and ETH Zurich alongside Indian academic partners and development organisations. JK Lakshmi Cement has been associated with the LC3 initiative since 2014 and worked with EPFL, IIT Delhi, IIT Madras, Development Alternatives and Technology and Action for Rural Advancement. The company conducted one of the earliest industrial trials of LC3 and recently announced commercial production of Green Pro LC3 cement from its Jaykaypuram plant in Rajasthan.

India remains the world’s second-largest cement producer and expansion of infrastructure, urbanisation and housing demand continue to support long-term sector growth, increasing interest in low-carbon technologies. The company reported an annual turnover of more than Rupees (Rs) 60 bn and current cement capacity of about 18 million (mn) tonnes (t) per annum, with a target of reaching 30 million (mn) tonnes (t) by 2030. Apart from grey cement, the company also makes ready-mix concrete, gypsum plaster, wall putty, primers, adhesives and fly ash blocks, and both sides concluded on the need for continued collaboration to develop sustainable construction solutions.