Asphalt

At the company's North American network of asphalt plants high-quality, innovative asphalts are produced using the latest processing technology. Lafarge asphalt materials are designed to provide enhanced performance and with sustainable construction, a growing concern for all industry stakeholders, provides environmentally responsible solutions to client's needs.

At the heart of all our asphalt operations is safety - Lafarge is committed to providing a safe work environment and to conducting its various businesses in a safe manner. Health and safety are core business values that are incorporated into all aspects of our asphalt operations.

Durapave®

Roller Compacted Concrete

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Manufacturing Process

Hot Mix Asphalt (HMA) Manufacturing

The basic purpose of a hot mix asphalt (HMA) plant is to properly proportion, blend, and heat aggregate and liquid asphalt cement to produce an HMA that meets the requirements of the job mix formula (JMF) (Roberts et al., 1996). Modern HMA plants also have the ability to incorporate reclaimed asphalt pavement (RAP), mineral filler, fibers, and anti-stripping agents, and will have advanced environmental systems to limit noise and dust emissions.

There are two basic types of HMA plants commonly in use today: the batch plant, and the drum mix plant. Batch plants produce HMA in individual batches while drum plants produce HMA in a continuous operation.

How HMA Is Made

Hot mix asphalt (HMA) is produced in a manufacturing plant that proportions, blends, and heats aggregate and liquid asphalt cement to produce a material that conforms to the specific product mix design and job mix formula (JMF). The JMF ensures that the HMA produced will provide the designed performance characteristics of that particular mix (durability, stability, rut resistance, skid resistance, and so on).

There are two basic types of HMA plants commonly in use today: batch plants and drum mix plants. As their name implies, batch plants produce HMA in individual batches, whereas drum plants produce HMA in one continuous operation. Both types of production plants produce the same HMA, and a mix produced in one will perform the same as a mix produced in the other. The choice of a batch or drum mix plant depends upon on business factors such as purchase price, operating costs, production requirements, and the need for flexibility in local markets.

Batch Plants

Drum Mix Plants

Batch plants, which produce HMA in individual batches, tend to be smaller-volume output plants than drum mix plants. However, they offer greater flexibility in the amounts of a particular mix they can produce, the variety of materials that can be incorporated into one batch, and their ability to produce small batch sizes. Typical batch quantities range from 2.0 to 5.5 metric tons of HMA, running at production capacities of up to 350 metric tons per hour, with each batch taking 15 to 45 seconds to make.

Drum plants produce HMA in a continuous manner and generally offer higher production rates than batch plants for comparable cost. Typical production rates for drum plants vary from about 100 metric tons per hour to more than 900 metric tons per hour, depending on the drum design.

Drum plants are suited to continuous production runs and are generally restricted in both the size of the smallest volume they can mix and the amount of different materials they can mix. Due to their method of operation, however, in general drum mix plants generally can incorporate higher levels of recycled material than batch plants.

Sustainability

Hot Mix Asphalt - The Sustainable Solution

Lafarge Asphalt supports sustainability in construction through material conservation, reduced energy costs, water preservation, noise reduction, and long-life pavements.

Hot Mix Asphalt Is Sustainable

Asphalt is widely recognized as one of the most recyclable construction materials in use on the planet today. Lafarge North America typically incorporates up to 30 percent of reclaimed asphalt pavement (RAP) back into new asphalt production, reducing total life-cycle greenhouse gases by 10 percent. Hot Mix Asphalt (HMA) pavement is the most recycled material in the United States; each year more than 100 million tonnes of asphalt pavement is reused or recycled into new pavements.

Lafarge asphalt operations do not just recycle RAP but our mixes utilize waste material from other industries, with roofing shingles, tire rubber, glass, and spent rail ballast all being incorporated into new asphalt production.

Currently, 100 percent of the asphalt supplied can be recycled. Even more important, it can be recycled at the highest point in the asphalt value chain-back into new asphalt construction-without detriment or compromise to the quality of the finished product.

Sustainable construction is a growing concern for all stakeholders, from state governments with major highway projects to parking lots for grocery chains that also want to demonstrate a commitment to the green agenda.

Lafarge is promoting and driving sustainability on five fronts:

Recycling

Lafarge has incorporated the latest technology in our asphalt plant network and where mix types and specifications can add up to 40% RAP.
Lafarge North America is the leading recycler of asphalt shingles into HMA.

Energy Consumption

Lafarge North America has taken an industry-leading stance on the development of Warm Mix Asphalt (WMA).
Duraclime® is produced and laid at lower temperatures than traditional asphalt and provides energy savings through reduced drying and heating costs as well as substantially reduced overall carbon emissions.
Duraclime has the double advantage of being able to incorporate recycled material.

Water Preservation

Porous Asphalt Pavement is a paving solution that allows surface water to ‘drain' through the upper layers of material. Spray and water runoff are reduced, increasing safety and promoting rapid infiltration and groundwater recharge to reduce erosion and particulates to improve overall water quality.
This pavement design can also allow water to be trapped by an impermeable layer or stone recharge bed within the overall construction. The system is designed to collect rain and storm water which can then be reused by adjacent commercial or residential facilities.

Perpetual Pavements

Perpetual asphalt pavements are designed to provide long-lasting construction where maintenance involves the removal and replacement of only the upper layers (all the material removed can then be recycled back into the new asphalt layer).
The total structure will not need to be replaced, which eliminates the emissions related to complete removal and replacement. Since only the upper layers need to be replaced, the maintenance and rehabilitation times are greatly reduced, further reducing the emissions caused by construction delays.

Noise reduction

In general, asphalt tends to provide a much smoother pavement than alternative materials. Research has demonstrated that Heavy Goods Vehicles (HGVs) driving on a smooth asphalt pavement will use 4.5 percent less fuel than when driving on a rougher grooved surface.
Durawhisper® is a proprietary asphalt mix that uses crumb rubber to make a thin open textured material that can reduce noise levels by up to 10DBa.