Two numbers from the same survey answer the question this technology is usually credited with settling. American producers made 172.0 million tons of asphalt mixture using warm-mix technologies during the 2023 construction season, which was 39.1 percent of the estimated national market. Of that tonnage, 78.8 million tons were produced with a temperature reduction of at least 10 degrees Fahrenheit. The remaining 93.2 million tons were made with warm-mix technology at conventional hot-mix temperatures.
The figures come from the fourteenth annual industry survey, published in April 2025 by the National Asphalt Pavement Association under a Federal Highway Administration agreement. They are the closest thing to a national count that exists, and they mean that a majority of the tonnage the industry reports as warm mix delivered no temperature reduction at all, and therefore none of the energy saving the technology is named for.
What the temperature actually has to fall by
The mechanism is straightforward and the definitions are looser than the mechanism. FHWA’s guidance from its Every Day Counts program describes warm-mix asphalt as a general term for technologies that reduce the temperature needed to produce and compact asphalt mixtures, and puts typical hot-mix temperatures at 300 to 350 degrees Fahrenheit with warm mix produced 30 to 120 degrees lower. The technologies use water, water-bearing minerals, chemicals, waxes and organic additives, or combinations, and FHWA notes that most require relatively simple plant and mix design modifications to introduce the temperature-reducing agent into either the mixture or the binder stream.
The threshold the national survey uses is far lower than that range. NAPA counts a reduction of at least 10 degrees Fahrenheit, which is roughly a tenth of what some products claim. Even against that low bar, 45.8 percent of warm-mix tonnage qualified in 2023.
FHWA’s own technology page, last updated in February 2025, lists reported temperature reductions for individual proprietary products running from 18 degrees at the low end to around 100 degrees at the high end. The page carries two disclaimers that a reader should not skip. It states that the products are listed for information only and that FHWA does not endorse any particular proprietary product or technology, and it says the applications should be considered experimental. A federal page still carrying that language in 2025, for a technology in use on nearly two fifths of national tonnage, is itself a finding about how the evidence has developed.
The technology mix inverted, and nobody announced it
The survey’s longest data series records something more interesting than the tonnage. In 2010, production plant foaming, which introduces a small quantity of water into the hot binder and expands it into a foam, accounted for 92.0 percent of warm-mix production. Chemical additives accounted for 6.0 percent.
By 2023 those shares had reversed. Plant foaming was down to 30.3 percent and chemical additives were up to 67.9 percent. Organic additives held 1.2 percent. Additive foaming recorded no reported use at all in 2023 after holding small shares in earlier years, and that category is the one covering the water-bearing minerals FHWA lists among the warm-mix technologies.
Foaming requires plant hardware and no consumable. Chemical additives require a consumable and minimal hardware. A market moving decisively from the first to the second is a market where the decision has stopped being a capital investment and become a per-ton purchase, and it changes who in the supply chain has to be persuaded of the benefit.
Why a producer buys warm mix and keeps the burner hot
The survey explains the gap between the two headline numbers without editorializing. Warm-mix additives, it notes, can have compaction, workability, antistrip and other benefits that encourage their use even when a reduction in production temperature is not sought or achieved by the producer.
Those benefits are real and they are the reason the technology spread. The survey’s background section lists what warm mix buys a contractor beyond fuel: the ability to extend the paving season into cooler months, to haul material longer distances, to improve compaction at lower temperatures, and to use higher percentages of reclaimed asphalt pavement. That last item connects the two resource-efficiency stories, since a stiff aged binder recovered from millings compacts more easily in a mix that stays workable, and it recurs in how recycled asphalt is used in road projects.
The survey also reports that of the 113 producers who used warm-mix technologies in 2023, 52 used them at both reduced and hot-mix temperatures, 32 used them only at reduced temperatures, and 29 used them only at hot-mix temperatures. Producers working at all temperatures typically did not vary the technology by temperature, so the difference between the reduced-temperature and hot-temperature columns comes mostly from the two groups that work only one way.
An additive bought for workability is not a failure. It is simply not an emissions measure, and a specification that credits the technology rather than the temperature will buy the first and report the second.
What the fuel and emissions figures cover
The numbers most often quoted for warm mix come from FHWA’s Every Day Counts material, dated November 2016, and they are reported ranges rather than measured results. The reduction in fuel consumption typically ranges from 20 to 35 percent, that guidance says, with up to 50 percent reported for some technologies, and a range of 15 to 70 percent reduction of carbon dioxide and other emissions during production has been reported.
Those figures need qualification before they travel. They describe production at the plant, which is one part of module A3 in the life-cycle accounting that embodied carbon measurement uses, and they say nothing about the aggregate, the binder or the haul. They are attributed as reported rather than as measured, with no single method behind the spread. And they apply to production that actually ran cooler, which the national data now shows is a minority of warm-mix tonnage.
FHWA’s technology page is candid about the state of the evidence in a sentence written years ago and still current: the benefits in energy savings and air quality are promising, but the technologies need further investigation and research to validate their expected performance and added value. That is the position to argue from, and it is not the position most warm-mix marketing takes.
The national count is voluntary, and its base is shrinking
How these figures were produced governs what they can carry. NAPA fielded a voluntary survey between January and December 2024 covering the 2023 season, collecting responses from producers in 49 states and the District of Columbia. A total of 201 companies operating 1,079 plants participated, reporting 439.7 million tons of asphalt mixture. National figures are estimates scaled from that base, and state-level results are withheld where fewer than three producers in a state responded.
The base is getting smaller. Responding companies fell 17 percent from the previous year and reporting plants fell 21 percent, and 18 percent of the companies that responded for 2023 had not participated for 2022. The share of respondents using warm-mix technologies has also declined from its own peak, from 78 percent in 2015 to 56 percent in 2023, which is a fact about who answered as much as about who used it.
Geography varies more than the national average suggests. Warm mix exceeded half of total asphalt production in 17 states in 2023. Six of those reported it at 75 percent or more of production: Connecticut, Louisiana, Nevada, New Mexico, Oregon and Pennsylvania. Five other states reported no asphalt production with warm-mix technologies at all, and they were Delaware, Hawaii, Kansas, Montana and North Dakota. By customer sector, 44.9 percent of state DOT tonnage used the technologies against 31.2 percent for commercial and residential work, so public agencies are the ones driving whatever adoption exists.
The unit a specification should actually reward
The honest measure of a warm-mix program is not tons of warm mix. It is tons produced at a temperature that actually dropped, and since 2018 the national survey has been structured to report exactly that split, after earlier editions were found to have captured the use of the technologies better than the use of reduced temperatures. Where the resulting figure fits in the wider accounting for a project’s materials is set out across more on sustainable infrastructure, and the plant processes a temperature reduction acts on are described in how asphalt is made.
An agency that wants the energy saving has an unusually clear instrument available, because the distinction has already been drawn for it in the data its own production will be benchmarked against. A specification can require a documented mixing temperature rather than the presence of an approved additive. That is a plant record rather than a product certificate, and the difference between the two requirements is 93.2 million tons a year.