This mini review focused on studies documenting the feasibility and impacts of secondary recycling of plastic waste in construction materials published online from 1992 through 2022. Using ScienceDirect and Google Scholar, our search included the terms: “plastic waste in construction materials,” “plastic waste building materials,” and “plastic waste in built environment.” We included studies presenting original research published in peer‐reviewed journals, government reports, and academic theses. Primary recycling of plastic waste was not included.

In total, we reviewed 100 studies (Figure 1). Most of these were published primarily between 2012 and 2022 (n = 92). Across studies reviewed, both homogenous and mixed plastic wastes were used in construction materials, and included:

• acrylonitrile butadiene styrene

Some of the plastic waste also required chemical additives for processing. Several studies examined use of more than one type of plastic waste, and/or assessed the production of more than one type of construction material. (Supplementary Datasheet S1)

Sixty-one studies examined plastic composites. Composite mixtures incorporated plastic waste with:

• banana fiber (n = 1)

Other studies examined incorporation of plastic waste into:

• acoustic and thermal insulation (n = 1)

Of the 100 studies, incorporation of plastic waste into construction materials was portrayed as a net positive (64%); net neutral (26%); or net negative (10%) sentiment, determined by each study’s final recommendations on researched materials. Primary benefits and risks spanned economic, environmental, human health, performance, and social impacts. Few studies addressed aesthetic impacts. Some applications of plastic waste in construction materials are in early test phases and less feasible to produce at scale, such as producing wood adhesives by chemically recycling polyurethane foams (Beran et al., 2021), so less was known about their impacts.

Several of the studies used LCAs (Muralikrishna and Manickam, 2017) to evaluate use of plastic waste in construction materials. LCAs are designed to capture economic, environmental, health, social, and other important factors. However, we note LCAs of emerging technologies are challenging to compare due to a lack of existing data, which can present uncertainty (Thonemann et al., 2020). Furthermore, LCAs can lack quality data and employ unclear boundary choices that may exclude a complete assessment of key parts of the full plastic life cycle (Miller, 2022). An important factor missing from the literature is the impact on human health, which is adversely affected by contact with plastic waste, and intersects all pillars of a triple bottom line approach to sustainability (Omer and Noguchi, 2020).

Figure 1 illustrates a summary of studies evaluating plastic waste in construction materials. Here, we outline where studies have evaluated or discussed the economic, environmental, health, performance, and social implications of these practices, and whether those impacts were described as costs or benefits for each material category.

The economic cost of utilizing plastic waste as a secondary or primary component in construction materials appears competitive compared to traditional construction materials. However, indirect costs may be underrepresented in these studies. Research on other waste materials, such as fly ash waste, which has been used in some construction materials since the 1970s, indicates costs increase when wastes are transported to processing sites (Sandanayake et al., 2020). In a few cases, elevated production costs resulted in an economic downside, particularly when additional processing or complex technologies were used. Further, economic benefits were dependent on numerous factors, including: cost-effectiveness of collecting, sorting, and preparing plastic wastes for downcycling; costs of producing the materials; establishment of markets for these materials; and construction, maintenance, operation, and end-of-life costs (Alqahtani et al., 2021). Many of the costs unaccounted for in plastic production (Tejaswini et al., 2022) are addressed in this mini review.

While studies emphasized the longevity of plastics, they lacked discussions of the fate of plastic-laced construction materials at their end of life. It is unclear whether downcycled materials can themselves be effectively reused. For example, a majority of road pavement is recycled in situ and can be recycled multiple times (Turk et al., 2016), but cannot be recycled indefinitely. Construction and demolition waste accounts for an estimated 30 percent of all wastes generated globally. Ultimately, materials will be incinerated or sent to landfills at the end of their useful lives. Moving the construction sector toward circularity in the future involves deconstructing and evaluating the quality of different materials, handling hazardous waste, developing advanced processing for recovery, as well as incentivizing material recovery and reuse (Purchase et al., 2022).

Most studies highlighting environmental benefits focused on diversion of discarded plastic waste from landfills and the environment. However, studies frequently overlooked production of microplastics and nanoplastics, a key effect of processing and using plastic waste (Hartmann et al., 2019; Rahman et al., 2022). Shredding or pelletizing homogenized or mixed plastic wastes for incorporation into asphalts, composites, lumbers, and synthetic turfs generates microplastics and nanoplastics. These particles, along with chemical additives and sorbed contaminants (e.g., heavy metals and legacy POPs), travel widely through ecological compartments—including but not limited to the air (Amato-Lourenço et al., 2020), the ocean (Eriksen et al., 2023), and soils (Cramer et al., 2022)—and into living bodies including humans (Amobonye et al., 2021). An identified environmental risk is the need to incorporate additive chemicals and/or new materials to plastic waste to maintain structural and performance integrity, which diminishes a material’s circularity and safety (Parece et al., 2022).

The reviewed literature was most critical of the environmental impacts of synthetic turfs, which are typically composed of many layers of plastics including micro-sized crumb rubber from synthetic automobile tires. Crumb rubber particles and their leachates are easily transported from the material into surrounding environments where they threaten ecosystem and human health (Armada et al., 2022; Murphy and Warner, 2022). These and other plastics are known to contain a wide range of toxic additives that contribute to environmental and human health burdens, exacerbating barriers to their safe recycling and reprocessing in a circular economy (Wagner et al., 2020).

Studies occasionally cited benefits to people via employment (e.g., informal waste sorting, recycling, production of construction materials) in the Global South (Estil, 2019; Kumi-Larbi, Jr. et al., 2022). However, no studies identified potential health costs of plastics, microplastics, or chemical exposures in this informal sector. Research documents serious health hazards linked to work in informal waste picking (Alfers, 2022; Zolnikov et al., 2021), especially in poor communities of color who work unprotected and lack access to reliable healthcare (Morais, 2022).

While the full human health impacts of microplastics and associated chemicals are still emerging, microplastics damage human cells in vitro (Danopolous et al., 2022) and cause serious illness in wildlife, such as seabirds (Charlton-Howard et al., 2023). Presence of plastic particles have been reported in blood (Leslie et al., 2022), breastmilk (Ragusa et al., 2022), feces (Zhang et al., 2021), human lungs (Jenner et al., 2022), placenta (Ragusa et al., 2021), testes and semen (Zhao et al., 2023), and venous tissue (Rotchell et al., 2023). Although all people living in a built environment made from plastic waste are at risk of absorbing, ingesting, and inhaling hazardous plastic particles and chemicals (Domenech and Marcos, 2021), those involved in producing construction materials from plastic fragments and items may be at an even greater risk through occupational exposure (Murashov et al., 2021).

Beyond the particles themselves, plastics are associated with over 10,000 chemical substances, very few of which have undergone rigorous toxicity testing and assessment (Wiesinger et al., 2021). Synthetic turf fields and plastic-asphalt roads offgas hazardous chemicals (including hydrogen chloride) known to originate from plastics, especially under hot climatic conditions or during melting in production (Pavilonis et al., 2013; Sabradra, 2017). The human health impacts of chemical offgassing from plastics is largely unknown.

Performance benefits varied across construction materials. For structural materials, including composites and bricks, performance benefits include: cohesive strength, compressibility, flexural strength, seismic performance, shear strength, and thermal insulation. For roadways, performance benefits include ability to withstand cracking, rutting, and other effects of weathering; perform well on fatigue tests; and show limited stiffness with high tensile strength. Across the studies, synthetic turf had the fewest performance benefits, and was limited to providing additional cushioning for athletes who use fields for sport (Pavilonis et al., 2013). Some of the applications of plastic waste in construction materials are still in early development, such as with producing wood adhesives by chemically recycling polyurethane foams (Beran et al., 2021), so their performance is not yet well understood.

Further, in some construction materials, while the addition of plastic waste may show no risks to performance or may even slightly enhance performance (e.g., Rahman et al., 2022), several studies showed clear performance risks across various uses of plastic waste in construction materials, particularly when increased amounts of plastics were used. For example, when producing asphalt from plastic waste, the smallest quantities of plastics incorporated (e.g., less than 5% of total asphalt mixture) were most beneficial to performance (Santos et al., 2021). The quantity of plastic waste that can potentially be sequestered in construction materials is inherently limited and should not be oversold.

We found construction materials made from plastic waste were often recommended for application in the Global South. Across studies, these materials were generally not recommended for large or multi-story structures due to strength- and/or integrity-related performance risks. Flammability was identified as a major concern (Gulhane and Gulhane, 2017). Research shows constructions made of synthetic materials, chiefly plastics, burn more intensely and quickly than constructions made of natural materials like wood (Kerber, 2012).

A net positive asset of plastic waste was its flexibility and heat-insulating characteristics when incorporated into construction materials, potentially making it well suited for temporary housing applications in refugee camps and slums (Estil, 2019; Haque and Islam, 2021; Zuraida et al., 2023). However, the propensity for heavy rains and natural disasters in the Global South can threaten infrastructure, and infrastructure made from plastic waste, including roadways, may be more vulnerable (Sabrada, 2017).

Incorporation of plastic waste into construction materials is still in its infancy and its focus has centered on the potential environmental and social benefits (e.g., cleanup and housing). The exposure and subsequent harm these practices may cause to humans however remains unquantified. Specific research gaps include investigations into potentially hazardous employment (e.g., from creating plastic bricks) and unsafe housing/infrastructure, as well as the short- and long-term health consequences.