EPS as Aggregate in Lightweight Concrete
Lightweight concrete (LWC) is produced by mixing lightweight aggregates, for example, vermiculite, pumice, clay, or by air-entraining agent in the concrete mix.14 When EPS is utilized as the aggregates, an LWC that is stronger and lighter than vermiculite concrete is produced. Figure 2 shows the visual comparison between EPS and vermiculite LWCs.14 Often, more than one type of aggregate is used to produce LWC with better physical and mechanical properties. For example, Demirel15 added both pumice and EPS aggregates in the concrete mix to construct an insulation block with lower density and thermal conductivity. Waste material such as paper sludge ash is also added as aggregate in conjunction with EPS aggregate to produce sustainable lightweight mortar that adheres to EU standards for masonry, rendering, and plastering mortars.16
The compressive strength of EPS concrete is governed by the quantity of EPS, followed by the water to cement ratio.17 Previous studies reported that the compressive strength of EPS concrete increases as its density increases.17, 18 Liu and Chen19 also reported similar finding using ultrasonic testing whereby the EPS particle size affects the mechanical properties, that is, flexural strength of the EPS concrete. Sayadi et al.20 studied the effects of EPS particles on fire resistance, thermal conductivity, and compressive strength of foamed concrete. This article concludes that based on the experiment involving foamed concrete and EPS LWC of different densities and volumes, the volume expansion of EPS leads to remarkable reduction in thermal conductivity, fire endurance, and compressive strength of the concrete. Application of LWC allows reduction in structural dead load and cross sectional of elements, that is, columns, beams, braces, and plates. In addition, LWC-derived structure is lighter thus lessen the impact of earthquake. Moreover, by using LWC, longer spans, thinner sections, and better cyclic load response can be obtained.21
EPS is nonpermeable, hydrophobic, and has closed-cell structure. The hydrophobic characteristic of EPS resulted in low thermal conductivity of polymer-calcined clay complexes.22 It was introduced in 1973 by Cork to address the issue possessed by conventional lightweight aggregates such as pumice, fly ash, oil palm shell, and waste rubber whose porous structures have resulted in high absorption value and water demand.23–28 EPS concrete has prospective application in structural elements (e.g., cladding panels, composite flooring systems, and load-bearing concrete blocks), insulated concrete, and protective layer due to its above-average energy absorption.29 For instance, EPS has cushioning properties that allows it to be utilized as buffer layer on top of debris dam to reduce impact force and lengthen the impact time caused by massive stones during the event of debris flow.30
When EPS is utilized as lightweight aggregate, the beads float and integrated poorly with the cement matrix because of their low density and hydrophobic properties.20 Hence, the low interfacial bonding strength and poor dispersion between the beads and matrix are solved by using bonding additive, for example, epoxy resin or water-emulsified epoxies. Alternatively, mineral admixture such as fly ash or silica fume can also works as bonding additive.31 In contrast to normal aggregates, concrete with EPS aggregates has shown to have better resistant against chemical and corrosion due to inert characteristic of EPS.20
Based on dynamic cyclic loading carried out by Shi et al.,32 the paper suggests that EPS concrete can be implemented in application that requires long-term cyclic loading such as protection of buried military structure due to its durability and energy absorbing properties. Despite of being lightweight and having good energy-absorbing property, EPS concrete suffers poor workability and low strength as low weight EPS beads are susceptible to segregation during casting process as reported by Liu and Chen.19 In this article, sand-wrapping method was employed by partially substituting the coarse and fine aggregates with EPS beads and using fine silica fume as bonding additive which resulted in improved density and compressive strength of EPS concrete.
In addition, reinforcement of EPS concrete using steel fiber has enhanced the drying shrinkage.33 In experiment by Pecce et al.,34 corrosion-resistant internal reinforcement such as zinc-coated steel bars are employed onto EPS concrete (see Figure 3) to address the issue of its increased porosity that cause it to prone to penetration. Even though this type of reinforcement increases the bond strength, it causes the EPS concrete to be more brittle as the failure mode changes from pull-out to splitting.
Many studies have been conducted on waste EPS-derived concrete. The EPS is recycled as aggregate for LWC and its properties are examined and compared with other conventional materials in order to promote sustainability development. For instance, Dissanayake et al.35 constructed three single storey houses from three different materials; burnt clay brick, cement sand block, and recycled EPS. Figure 4 shows the house’s wall made with EPS panels. Despite their similar performances in embodied energy, carbon emission, and cost, the paper suggests that recycled EPS is greener alternative for conventional walling material especially in location that has short supply of sand. Hernández-Zaragoza et al.36 also reported that recycled EPS aggregates could replace sandy material to produce less permeable, more flexible, and relatively cheaper lightweight mortar that still comply with Mexico masonry standard.
In addition, EPS waste can be recycled as resin for composite production. Bhutta et al.18 carried out an experiment where EPS waste is recycled into resin for production of polymer mortar panels (PMPs) by mixing the waste in methyl methacrylate (MMA) solution. Based on flexural behavior test, the EPS–MMA-based PMP has better flexibility and high load-bearing capacity than polymer-impregnated mortar panel. EPS waste can also be dissolved into resin using solvents such as toluene and acetone to produce polymer–cement composite that has potential as commercial construction material and radioactive waste deactivator.37
Also, Kaya and Kar38 conducted an experiment involving concrete made from different compositions of waste EPS, cement, and tragacanth resin. They conclude that concrete with high ratio of EPS to cement and resin exhibits high porosity and low density, thermal conductivity, compressive, and tensile stress. The formation of artificial pores leads to enhanced insulation properties. Hence, the paper suggests the application of EPS-aggregated and resin-added concrete for a more sustainable approach as well as reducing building load in construction industry. Bicer and Kar39 mixed EPS waste with tragacanth resin to produce filling material for gypsum plaster. This plaster has low thermal conductivity and it is applied as inner plaster for building insulation and decoration.
Decorative Tiles and Moldings
The purpose of decorative molding is to improve the overall aesthetic aspects of a building by concealing transition and gaps between surfaces. Figure 5 shows a sample of EPS decorative molding and Figure 6 shows how it is applied on the building. Currently, EPS has replaced stone as material for decorative molding as observed in North America and other countries where EPS is embedded with reinforcing mesh before polyurethane (PUR) or polymer modified cement coating is applied.40 Polymer foams are popular materials for decorative tiles and molding.
Besides that, EPS is a common thermal insulator in construction industry.2 Given its good thermal, structural strength, and water-resistance properties, EPS is one of the plastic foams that pioneered the development of structural panels known as insulated concrete foams. For example, EPS is specifically utilized in insulated vinyl siding.41 Siding is the formation of the outermost layer of a building. It offers protection against outside element as well as for decorative purpose. EPS foamed layer is attached to the back of regular vinyl exterior layer to improve insulation, stiffness, and strength of the siding.
Despite its function as decorative molding to improve building’s visual, Doroudiani and Omidian2 reported that EPS possesses harmful risk in terms of health and safety when used in residential areas and it should be eliminated unless the flammability issue was addressed. For instance, addition of diammonium phosphate flame retardant in a wood composite product made of wood flour and EPS waste improved the composite’s fire-resistant properties, making it safer to be used as floor, furniture, and decoration panel.42
EPS for Panel Applications
Structural Insulated Panel
Developed nearly 75 years ago, structural insulated panel (SIP) is a sandwiched panel utilized as structural element in concrete building, for example, wall, roof, and floor.43 It is a high-performance three-layered composite building panel used as elements in floors, walls, and roofs of steel or wooden frameworks for residential and light commercial buildings.44, 45 Usually, the panel is manufactured in a factory, and transported to a construction site to be assembled. SIP is consisted of three-layered structures by bonding a thin layer (facing) to each side of a thick layer (core). For example, in Figure 7
, the core is made of EPS sandwiched between two oriented strand boards (OSBs). The bending stress is supported by face sheets that are stabilized by the core. The core counters the shear load and elevates the structure’s stiffness by keeping apart the face sheets at fixed distance. As a result, SIP is superior to its constituents with regards to stiffness-to-weight ratio.46
Impregnation of wood-derived face sheets or facing material provides protection against water, wind borne debris, and biological degradation, for example, mold build-ups and termite attack. OSB is a conventional facing material in the production of SIP with EPS as a core.44 Performance-wise, SIP is considered a key component in modern day construction due to its high flexibility and strength. Although EPS core with significant water adsorption is less favored as insulation material because it will reduce the thermal efficiency of buildings.47
Generally, the thermal conductivity of EPS core decreases as its density increases.48 Sariisik and Sariisik49 experimented using pumice as SIP’s component. The insulation block consisted of EPS foam sandwiched in between two layers of pumice LWC (see Figure 8) is found to has low thermal and sound conductivity of 0.33 W mK−1 and 60 dB, respectively. Structural evaluation of SIP using computer software is also practiced by several researchers. Bajracharya et al.50 conducted a structural analysis of EPS sandwich panels for slab application using Strand7; a finite element-based software which produced results that are in good agreement with the experimental results thus expanding SIP usage in production of lighter structural slab with better heat and sound insulation. Moreover, based on ENISO-6946-compliance computer modeling result obtained by Ede and Ogundiran,51 composite EPS wall panel is shown to have higher load-bearing capacity and thermal resistance thus proven as feasible replacement for the traditional concrete hollow brick.
Hopkin et al.52 conducted a research on full-scale natural fire tests on gypsum-lined SIP and engineered floor joist assemblies. SIP was made up of two OSB facing plates and a core; polymer-based foam insulator such as EPS or PUR. The lightweight panels produced were applied in domestic building, for example, apartment blocks, schools, and hotels as principal component for load-bearing compression.52 In this study, the fire performance of SIP buildings with passive fire protection (PFP) specifications was assessed. Consequently, the low durability of SIPs structure is apparent regardless of the type of core used. There is high possibility of floor plate to collapse when PFP is poorly fixed or defined. However, system redundancies and alternative load paths saved the test structures from total demolition. Poorly sealed fitting components have allowed the fire spread mechanism to happen.
In South Korea, EPS foam is incorporated into concrete floor as resilient material to reduce noise and preserve heat, consequently saving more energy.53 The thermal conductivity of EPS foam decreases as its density increases. Park et al.54 constructed a study in vibroacoustic application of graphite-embedded EPS foam sandwiched between floors. Addition of graphite flakes into polystyrene matrix increases the thermal insulation since the graphite particles reflect radiant energy. The foam becomes stiffer as a result of change in morphology that restricting foam expansion. These improvements led to production of thinner and stronger insulation panel that diminishes the low frequency (below 100 Hz) floor impact noises. Despite the vibroacoustic properties of graphite EPS foam, the core-softening leads to decoupled behavior in sandwich floor which affects the insulation properties at certain frequencies.55 The reduction in dynamic stiffness of graphite-EPS causes the decrease in the degree of coupling between mortar bed and base slab as well as shifting of both coupled and decoupled mode to lower frequencies.
Composite SIP
Traditional SIP is consisted of foam core and wood-based facing. It is easily penetrated by wind borne debris and prone to biological degradation, for example, thermite attack and mold build-ups. The search for more effective alternative to overcome this problem has led to the use of composites panel. Chen and Hao56 propose that composite SIP (CSIP) with EPS foam core is applied as load-bearing elements in building, for example, roof, floor, and wall in order to protect the building envelope from being damaged by windborne debris during the event of natural disaster. CSIP is made by replacing OSB face sheets of SIP with thermoplastic composite face sheets to produce lighter and sustainable panel that are more resistant toward windborne debris and mold build-up.57 The CSIP is capable to be utilized as external wall given that the experimental results obtained by Vaidya et al.57 show that CSIP wall can support the wall loads and resisting windborne missile impact up to 2600 J.
Mousa and Uddin58 studied on the structural behavior and modeling of full-scale composite structural insulated wall panels. This article attempts to show that CSIP is a great candidate to replace the traditional SIP for housing applications. Thick and lightweight EPS core is sandwiched in between thinner face sheets made up of polypropylene (glass PP) laminate. This arrangement allows better transfer of bending stress and shear loads by face sheets and core, respectively. The core helps preserving faces from wrinkling or bulking.59 Also, the face sheets are kept apart by the core, which strengthen the structure.
In designing CSIP, factors such as deflection and debonding are heavily assessed in addition to the high strength resulted from face sheets and core combination. A full-scale experimental testing was conducted by Mousa and Uddin58 to study the behavior of CSIP walls under eccentric load. The pull-off strength test revealed that face sheets-core debonding was the main mode of failure. In this study, interfacial tensile stress between face sheets and core and the reaction of CSIPs wall under in-plane loading were predicted based on analytical model and finite element model, respectively. The results from both models were consistent with the experimental results. Moreover, the parametric finite element study showed that the structural integrity of CSIP wall panel was influenced by span-to-depth ratio and core density.
Many researches have analyzed the development of composite panels for building applications using rigid and soft cores with thermoset and thermoplastic face sheets.60–65 Compared to CSIP constructed using typical sandwich method, the developed CSIP boosts better strength and creep resistance due to 12.5 times more face sheets-to-core moduli ratio.59 CSIP is implemented as components in both structural (e.g., loadbearing walls, floors, and roofs) and nonstructural (e.g., nonload-bearing walls, lintels, and partitions) thanks to its low cost, high strength-to-weight ratio, and ease of assembly.
Furthermore, Smakosz and Tejchman46 investigated the strength, deformability, and failure mode of CSIP. This article assessed the mechanical performance of CSIP produced using EPS core and face sheets that were made from glass-fiber reinforced magnesia cement boards based on quasi-static full-scale and model tests under monotonic loading. The overall results indicate that CSIP is better than SIP in terms of mechanical and insulating properties. CSIP has higher strength which allows it to be applied as load-bearing components in building. Moreover, curtain wall or building envelope constructed using SIP is more energy efficient compared to timber framing.66 SIP insulation capability can be modified by changing the foam’s type and thickness. Despite its advantages, addition of SIPs into a structure requires thorough planning and use of costly construction crane or lift truck to handle big-sized panels.
Vacuum Insulated Panel
Vacuum insulated panel (VIP) is an evacuated open porous material inserted within multilayer envelope. VIP consists of inner core, barrier envelope, and desiccant as shown in Figure 9.67 The envelope protects the panel against external stress. VIP is categorized based on the type of material used as envelope; either thick metal sheet or metallized polymer film. EPS foam is used as core to maintain the vacuum condition as well as to provide support for the envelope. The desiccant is placed in the core as adsorbent in order to avoid infiltration by external gas or water vapor. Therefore, VIP is an alternative to conventional building insulation material. It creates vacuum inside the core which is effective in inhibiting the heat transfer. Additionally, the thermal conductivity of VIP can be reduced by decreasing the pore of open cell foam such as EPS.
Backfilling
Construction of embankment using heavy filling material resulted in several problems such as bearing failure and slope instability. Commonly, EPS geofoam is used as backfilling to reduce the weight of embankment especially when it is erected on top of soft soil.68
EPS geofoam is also used as backfilling material for bridge abutment and road widening.69 As lightweight fill, EPS is suitable for construction of ground embankment with low-bearing capability. Furthermore, it reduces the lateral forces on the back of bridge abutment’s structure. In a case study conducted in Thanet Way, England, EPS lightweight blocks were used to eliminate the lateral loading on bridge abutment and stabilized the weak foundation formed on chalk ground. The lightweight property of EPS block allows it to be carried and positioned easily without requiring any lifting equipment thus reducing transportation cost. The blocks were arranged in staggered conformation and steel bars were embedded to further strengthen the structure. Figure 10 shows the construction of Grimsøyvegen Bridge that utilizes EPS as the bridge abutment.
EPS is lightweight, waterproof and has good cushioning ability as well as ease of application. In Norway, usage of EPS geofoam as backfilling has prevented the gradual sinking of bridge deck by reducing the load applied to the weak foundation.71 Moreover, the road constructed using lightweight fill costs less than using traditional backfilling despite their comparable performances.72 Beju and Mandal73 found that the EPS geofoam with higher density has higher compressive strength and modulus values but lower absorption capacity compared to the lower density geofoam.
Besides its usage on embankment, EPS geofoam is also applied for slope stabilization of mountainous terrain as practiced by countries such as Norway and Japan.70, 74 Study by Arellano et al.75 shows that the lightweight fill stabilizes the slope by reducing weight and driving force of sliding mass. It increases the structural strength as the block is more resistant toward force by the landslide material. Additionally, Özer et al.76 propose that all slope stabilization application that involves EPS geofoam as backfilling must incorporated permanent drainage system to prevent foam’s instability due to hydrostatic and seepage pressure.
As mentioned before, EPS is suitable as backfilling material because it is lightweight, stronger and has good chemical, mechanical, and water stability. However, a cheaper alternative than EPS geofoam is proposed by Miao et al.68 that involves the mixture of EPS beads, soil, and binder for embankment backfilling. Based on the sand cone test and California bearing ratio test, the lightweight fill passed the specification for usage in bridge abutment and highway embankment.
Also, EPS is employed as base material in combine optic fiber transducer for landslide monitoring especially when it involves sandy clay slope.77
Properties of EPS
Fire Behavior and Thermal Insulation Properties of EPS
Polystyrene foam has similar fire behavior to most organic materials where both are easily combustible. Thus, tiny amount (<1%) of fire-retardant material is added to the EPS insulation product in order to enhance the fire retardancy of EPS. Besides fillers such as SiO2, Fe2O3, and clay, waste such as fly ash can also be used as cheaper alternative to increase the flame retardant of EPS foams. Wang et al.78 introduced fly ash into phenolic resin-hydrated aluminum hydroxide binder which is the incorporated into EPS foam. This insulation material is reported to increase the loss on ignition (LOI) value of EPS foam up to 29.6% and acquired the V-0 rating. Figure 11 shows that EPS foam sample treated with hydrated aluminum hydroxide and thermosetting phenolic resin has greater fire resistance during LOI test compared to other untreated samples. The leaching of fire-retardant material into environment is prevented since it is polymerized into the molecular structure of EPS.
The fire behavior of fire-retarded EPS is significantly different from nonfire retarded EPS. When exposed to heat, fire-retarded EPS shrinks away from the heat source. The probability of ignition of the material is reduced and welding sparks or cigarettes normally will not ignite it. However, in the construction industry, it is mandatory to use a flame-retardant grade of EPS to reduce the flammability and spread of flame on the surface of EPS products. The application of EPS in compartmentalization or fire protection of structure is restricted without incorporation of other fire-resistant material. This case was observed from previous studies where EPS was covered with gypsum and steel in order to address its fire behavior.79 The EPS was evaluated according to EN 13501-1 and categorized as “difficult to ignite.” The test also indicated that EPS gave out minimal smoke production.
According to Yucel et al.,80 studies were conducted on thermal insulation properties of EPS as construction and insulating materials. Thermal conductivity test provides information that determines the performance and suitable application for the insulating material. As construction equipment, insulation material has to comply with parameters such as temperature, humidity, and overall assembly condition. The laboratory test results are vital factor in characterization of structure and selection of total insulation-building assembly. The framework of the insulating material is evaluated based on its class, thermal conductivity, density, and mechanical properties. Using the plate method with thermal conductivity detection between 0.036 and 0.046 W mK−1, the EPSs with densities between 10 and 30 kg m−3 were tested for its construction-grade insulating performance. The results conclude that the insulating performance of EPS is influenced by material composition in cell, that is, homogenous, porous, or multilayer.
Production of Smoke
Smoke is described as visible suspension of solid or liquid particles in the gas as product of combustion and pyrolysis.81 Production of smoke can be suppressed by restricting the ability of material to ignite and reducing the flame spread and heat released.82
The surface area of EPS insulation must be protected using noncombustible material in order to minimize smoke production during event of fire.83 EPS begins to soften at temperature above 100 °C and upon further heat exposure, it will shrink, melt, and decompose to produce flammable gases which ignitable by spark or flame at certain condition and temperature.
Mechanical Strength of EPS
Studies were conducted to understand how grain size of EPS and additives such as fly ash and silica fume can enhance the mechanical properties of EPS-aggregated concrete.24, 84, 85 Ferrándiz-Mas and García-Alcocel86 performed a research on the durability of EPS mortar. In this article, several methods were used to observe microstructure in order to analyze the effect of EPS type and concentration on the strength of Portland cement mortars. Methods employed were capillary absorption of water, mercury intrusion porosimetry, impendence spectroscopy, and open porosity. The first method showed that EPS decreases the capillary absorption coefficient while the rest of the methods demonstrate inadequacy in elucidating the microstructure of EPS in mortar due to polymeric and spongy nature of EPS. Furthermore, both heat cycles and freeze–thaw cycles showed that EPS’s insulator property increases the compressive strength of the mortar. The workability of mortar is increased by adding air-entraining agent, water retainer, and superplasticizer additive. Hence, the paper concludes that EPS-aggregated mortar has enhanced durability and is feasible for more sustainable usage in masonry, stucco, and plaster mortar.
Several studies on characterization of EPS concrete using simultaneous optimization of both mechanical and thermal properties with respect to EPS parameters were performed.86 Recent articles have demonstrated the capability of self-compacting lightweight structure produced from nano-SiO2 and EPS.87 Other studies have attempted to combine EPS beads as filler with foamed cement paste matrix in order to synthesize thermal insulator composite. Additives are added to increase adhesiveness and reduce segregation of EPS beads from concrete matrix.88 EPS is utilized in the production of gypsum and plaster plates and panels.89 Fillers such as PP fiber and mixture of fly ash and metakaolinite are added to strengthen the plastic matrix as seen in the production of industrial components and lightweight inorganic polymer.90, 91
The EPS product is classified based on compressive strength and compressive stress. Compressive strength is maximum uniaxial compressive stress that material can bear before fracturing. Number is assigned to EPS product based on its compressive stress at 10% compression as shown in Table 1. Jablite is one of the many brands of EPS.
Mechanical Properties by EPS Type (Adapted from Ref. )
| Mechanical strength (kPa) | EPS 70 | EPS 100 | EPS 150 | EPS 200 | EPS 250 |
|---|---|---|---|---|---|
| Compressive strength @ 10% compression | 70 | 100 | 150 | 200 | 250 |
| Compressive strength @ 10% nominal strain | 20 | 45 | 70 | 90 | 100 |
| Bending strength | 115 | 150 | 200 | 250 | 350 |
Water and Moisture Absorption
EPS has very poor water absorption which decreases as density increases as shown in Table 2. EPS with 9–12 years of usage period has 8–9% of its volume filled under groundwater table.93 The cellular structure of EPS is water resistant, vapor permeable, and possesses zero capillarity though neither liquid water nor water vapor influences its mechanical properties. However, absorption of moisture is still possible upon complete immersion of EPS due to fine interstitial channels between molded beads.
Percentage (%) Volume of Water Absorption Adapted from Ref.
| Density (kg m−3) | After 7 days | After 1 year |
|---|---|---|
| 15 | 3.0 | 5.0 |
| 20 | 2.3 | 4.0 |
| 25 | 2.2 | 3.8 |
| 30 | 2.0 | 3.5 |
| 35 | 1.9 | 3.3 |
EPS geofoam is prone to moisture absorption which causes deterioration of thermal properties. Less than 10% volume of lightweight-fill geofoam is absorbed during its lifetime usage.94 Also, high density EPS possesses high water vapor diffusion resistance factor due to better moisture properties. Table 3 shows moisture properties of EPS of different numbers.
Moisture Properties of Jablite EPS (Adapted from Ref. )
| Moisture properties | EPS 70 | EPS 100 | EPS 150 | EPS 200 | EPS 250 |
|---|---|---|---|---|---|
| Water vapor diffusion resistance factor, μ | 20–40 | 30–70 | 30–70 | 40–100 | 40–100 |
| Water vapor permeability, δ mg Pa−1 h−1 m−1 | 0.015–0.030 | 0.009–0.020 | 0.009–0.020 | 0.006–0.015 | 0.006–0.015 |
| Vapor resistivity (MNs/g) | 145 | 200 | 238 | 238 | 238 |
Chemical Resistance
Chemical resistance of EPS is affected by the reaction time, temperature, and applied stress. It has identical resistance to general polystyrene. EPS is sensitive toward solvent attack which leads to softening and cracking of itself due to its thin cell walls and large exposed surface. Table 4 summarizes the chemical resistance of EPS with respect to the common reagents and solvents.
Selected EPS Resistant Behavior (Adapted from Ref. )
| Source of attack | Resistant behavior |
|---|---|
| Salt water (sea water) | Resistant |
| Alkali solutions | Resistant |
| Soaps | Resistant |
| Caustic soda solutions | Resistant |
| Bitumen (air blown) | Resistant |
| Silicon oils | Resistant |
| Alcohol | Resistant |
| Micro-organisms | Resistant |
| Paraffin oil, Vaseline, diesel oil | Limited resistance |
| Petrol (super grade) | Nonresistant |
| Strong oxidizing acids | Nonresistant |
| Fuming sulfuric acid | Nonresistant |
| Organic solvents | Nonresistant |
| Saturated aliphatic hydrocarbon | Nonresistant |
EPS does not react with water, salt, or alkali solution. The insolubility of EPS in most organic solvent influences the selection of adhesive, label, and coating of EPS product. In general, substance is tested for its compatibility with EPS by exposing molded polystyrene to it at 120–140 °F. Despite the ultraviolet radiation resulted in superficial yellowing and friability on molded polystyrene, its physical properties remain unaltered.
Toxicity and Environmental Effect
(1)(2)The volume of smoke and toxic gases released by EPS insulation material is determined by the material quantity and density. Normally, the surface of EPS insulation is fire-protected using gypsum, stone, wood or steel to prevent flame from spreading to EPS. Under normal fire situation, EPS melts due to heat flow. However, EPS might ignite when surface protection material is fully incinerated thus exposing it to direct fire followed by emission of smoke and combustion gases. The effect of fire-retardant material on the toxicity of EPS is negligible due to only small addition (0.5–0.1%) of the material is required. Hence, EPS produces significantly less toxic fumes as compared to natural material, for example, wood, wool, or cork.95
