Sulfuric Acid Exposure Research Articles

Towards sustainable construction: Harnessing potential of pumice powder for eco-friendly concrete, augmented by hybrid fiber integration to elevate concrete performance

This study investigates the innovative use of industrial waste pozzolana, specifically pumice powder (PP), as a partial replacement for cement, combined with hybrid fibers in concrete. Seven formulations varying PP content from 10 % to 35 % were tested, identifying 15 % PP as optimal. PP improved porosity due to its fineness, leading to better homogeneity, a refined microstructure, and an optimum compressive strength of 28.8 MPa with reduced permeability, enhancing durability. Hybrid fibers, including steel fibers (SF) from waste tires and polypropylene fibers (PF), improved toughness, ductility, and resistance to brittle failure. Tests on hybrid fiber-reinforced concrete (HyFRC) mixes with 1 % and 2 % hybrid fibers showed up to an 18.09 % increase in compressive, tensile, and flexural strengths. Energy dissipation in compressive response improved by 544.20 %, while flexural and splitting responses increased by up to 299.65 % and 208.57 %. Durability assessments in hydrochloric (HCl) and sulfuric acid (H2SO4) exposure revealed the synergy of fibers and PP enhanced resistance to chemical degradation, with high PF mixes losing as little as 0.04 % strength. Scanning electron microscopy (SEM) confirmed a dense, well-bonded matrix with reduced porosity. Analytical characterizations of mixtures such as energy dispersive x-ray spectroscopy (EDX) were studied. Regression models developed using Popovic’s and Mander’s models, accurately predicted HyFRC stress-strain behavior, closely aligning with experimental results. The integration of PP and hybrid fibers not only improved mechanical properties but also extended service life in harsh environments, offering a cost-effective, sustainable concrete solution.

Development and assessment of eco- and user-friendly geopolymeric stabilizers for sustainable soil improvement

This paper presents an innovative approach to address inherent limitations in traditional geopolymerization methods by focusing on producing eco and user-friendly mechano-chemically activated geopolymeric (M-GP) stabilizers for soil stabilization applications. A comparative analysis is conducted to benchmark the effectiveness of these stabilizers against conventionally activated geopolymer (C-GP) stabilizers. The study also investigates the influence of ground granulated blast furnace slag (GGBFS) amount on the mechanical and durability characteristics of stabilized soil specimens. Furthermore, the effect of activation techniques on the efficacy and strength of soil after sulfuric acid (H2SO4) exposure was investigated. The durability performance was evaluated by submerging the samples in a 1 % H2SO4 solution for a period of 60 and 120 days. The evaluation addresses various aspects such as visual appearance, mass changes, unconfined compressive strength (UCS), ultrasonic pulse velocity (UPV) and the Fourier transform infrared spectroscopy (FTIR) of geopolymer-stabilized soil samples. Results indicate that the UCS of M-GP samples surpassed C-GP-stabilized soil by 12–45 %. Moreover, the geopolymer-stabilized soil exhibited a significant increase in strength, with improvements of 114 %, 247 %, and 361 % observed at GGBFS content levels of 50 %, 75 %, and 100 % by weight, respectively. After exposure to the H2SO4 solution, M-GP-stabilized soil demonstrated superior resistance to sulfuric acid compared to C-GP-stabilized soil. The residual ultimate compressive strength (UCS) for M-GP and C-GP specimens was 80 % and 76 % respectively after being subjected to the H2SO4 solution for 60 days. However, these values further declined to 53 % and 48 % after 120 days of exposure. In addition, the result showed that geopolymer-stabilized soil containing 75 % slag exhibited superior resistance to H2SO4 compared to other stabilized soil samples.

Sulfuric acid-induced skin neoplasms in immunocompetent mice.

This study investigates the carcinogenic potential of chronic dermal exposure (16 weeks) to sulfuric acid (SA) in immunocompetent mice. Clinical assessments, histopathological analyses, immunohistochemical analyses and biochemical assays were conducted to evaluate skin irritation, oxidative stress biomarkers and the potential carcinogenic effect of SA. Results indicated that prolonged exposure to SA leads to various alterations in skin structure, notably inflammation, preneoplastic and neoplastic proliferation in hair follicles, as well as hyperkeratosis and acanthosis, resulting in an increased epidermal thickness of 98.50 ± 21.6 μm. Immunohistochemistry analysis further corroborates these observations, showcasing elevated nuclear expression of p53 and Ki-67, with a significant mitotic index of (57.5% ± 2.5%). Moreover, biochemical analyses demonstrate that SA induces lipid peroxidation in the skin, evidenced by a high level of Malondialdehyde and a consequential reduction in catalase activity. These findings suggest that prolonged exposure to SA can induce skin neoplasms, highlighting the need for stringent safety measures in environments where SA is frequently used. This study underscores the potential occupational health risks associated with SA exposure.

Influence of Sulfuric Acid Exposure on Mechanical Properties of Alkali-Activated Concrete

Influence of Sulfuric Acid Exposure on Mechanical Properties of Alkali-Activated Concrete

Personal Exposure to Sulfuric Acid in the Electroplating Industry: Development and Validation of a Predictive Model.

This study aimed to measure personal exposure to sulfuric acid in the electroplating industry to establish a predictive model and test its validation. We collected indoor air parameters and related information from four electroplating plants. Silica gel sorbents were used to collect air samples using high-performance ion chromatography. We collected air samples from three plants (i.e., Plant B, Plant C, and Plant D) and applied multiple linear regressions to build a predictive model. Eight samples collected from the fourth plant (i.e., Plant A) were used to validate the model. A total of 41 samples were collected with a mean of 25.0 ± 9.8 μg/m3 (range 12.1-51.7 μg/m3) in this study, including Plant A (8 samples, 17.5 ± 2.8 μg/m3, 13.0-22.0 μg/m3), Plant B (11 samples, 36.5 ± 9.7 μg/m3, 23.1-51.7 μg/m3), Plant C (11 samples, 16.4 ± 1.7 μg/m3, 12.1-17.8 μg/m3), and Plant D (11 samples, 27.4 ± 1.7 μg/m3, 24.1-29.9 μg/m3). Plant B was significantly higher in sulfuric acid than the other plants. Workers from the electroplating process plants were exposed to sulfuric acid at 29.0 ± 11.5 μg/m3. The predictive model for personal exposure to sulfuric acid fit the data well (r2 = 0.853; adjusted r2 = 0.837) and had an accuracy of 5.52 μg/m3 (bias ± precision; 4.98 ± 2.38 μg/m3), validated by the personal sampling of the fourth plant. This study observed that sulfuric acid exposure was lower than the permissible exposure level of 1000 μg/m3 in Taiwan and the United States, and only two samples were lower than the European Union standard of 50 μg/m3. The developed model can be applied in epidemiological studies to predict personal exposure to sulfuric acid in plants using electroplating.

An investigation of methods to enhance adhesion of conductive layer and dielectric substrate for additive manufacturing of electronics

Additive manufacturing of conductive layers on a dielectric substrate has garnered significant interest due to its promise to produce printed electronics efficiently and its capability to print on curved substrates. A considerable challenge encountered is the conductive layer’s potential peeling due to inadequate adhesion with the dielectric substrate, which compromises the durability and functionality of the electronics. This study strives to facilitate the binding force through dielectric substrate surface modification using concentrated sulfuric acid and ultraviolet (UV) laser treatment. First, polyetheretherketone (PEEK) and nanoparticle silver ink were employed as the studied material. Second, the surface treatment of PEEK substrates was conducted across six levels of sulfuric acid exposure time and eight levels of UV laser scanning velocity. Then, responses such as surface morphology, roughness, elemental composition, chemical bonding characteristics, water contact angle, and surface free energy (SFE) were assessed to understand the effects of these treatments. Finally, the nanoparticle silver ink layer was deposited on the PEEK surface, and the adhesion force measured using a pull-off adhesion tester. Results unveiled a binding force of 0.37 MPa on unmodified surface, which escalated to 1.99 MPa with sulfuric acid treatment and 2.21 MPa with UV laser treatment. Additionally, cross-approach treatment investigations revealed that application sequence significantly impacts results, increasing binding force to 2.77 MPa. The analysis further delves into the influence mechanism of the surface modification on the binding force, elucidating that UV laser and sulfuric acid surface treatment methods hold substantial promise for enhancing the binding force between heterogeneous materials in the additive manufacturing of electronics.

The impact of original aggregate and attached mortar types of recycled aggregates on the sulfuric acid resistance of geopolymer recycled concrete

Recycled concrete aggregate (RA) is composed of original aggregate and attached mortar, both of which are essential in determining the durability and mechanical characteristics of recycled concrete. In this investigation, the sulfuric acid resistance of geopolymer concrete (GPC) was assessed using various RA types, incorporating limestone and quartz as original aggregates, and geopolymer and cement as the attached mortars. The results revealed that although the presence of RA accelerated the degradation of GPC, the concretes maintained a compressive strength of over 20 MPa and exhibited a mass loss ratio of less than 13 % after withstanding 91 days of sulfuric acid exposure. These results suggested that RA was viable to be utilized in environments subjected to acid attack. Notably, when quartz was used as the original aggregate, the GPC demonstrated remarkable acid resistance; the compressive strength and mass loss ratio were minimally affected, at just 1.7 % and 5.8 % respectively. Moreover, the geopolymer, when serving as the attached mortar, exhibited excellent compatibility with the new mortar within GPC, fostering the development of denser interfacial transition zones (ITZs). These robust ITZs played a pivotal role in mitigating the detachment of RA under acidic conditions. Conclusively, for concrete structures in acidic environment, the optimal selection of RA entailed pairing quartz as the original aggregate with geopolymer as the attached mortar. This combination provided superior acid resistance and extended the durability of the concrete.

Laboratory investigation on the fracture toughness (Mode I) and durability properties of eco-friendly cement emulsified asphalt mortar (CRTS II) exposed to acid attack

Cement Emulsified Asphalt Mortar (CEAM) has gained prominence as a vital material for its energy and noise damping properties between the concrete roadbed and track slab in a high-speed railway system. Therefore, it is evident that CEAM properties need to be better understood and optimized. Since cracking caused by traffic loading and atmospheric conditions is one of the primary causes of failure in CEAM, addressing this issue is of great importance. Furthermore, there is a growing need for more environmentally friendly and durable CEAM due to the environmental impact of cement production in the form of greenhouse effect. The objective of this study is to assess the impact of partially replacing cement content in CEAM Type II (CRTS II) specimens with pozzolanic materials such as silica fume, metakaolin, and granite sludge to investigate how these pozzolans affect the fracture toughness (Mode I) performance under both normal (water curing) and sulfuric acid exposure conditions with the main focus on evaluating the pozzolans ability to resist acid attack from a fracture toughness perspective as the research novelty. For this purpose, specimens containing pozzolans at 5 %, 10 %, and 15 % substitution level (by weight of cement) were subjected to Semi-Circular Bending (SCB) test both under normal and exposure to 5 % sulfuric acid solution conditions. Moreover, water absorption test was conducted on specimens in normal condition as a durability index. The test results of this study revealed that substitution of these pozzolanic materials enhanced the fracture toughness in normal condition. Specifically, at a 10 % substitution as the optimal level, silica fume and metakaolin resulted in 18 % and 15 % increase in fracture toughness performance compared to the control specimen in normal condition. However, granite sludge exhibited almost the same performance as the control specimen at 5% substitution as its optimal level. In acid exposure condition, the detrimental effect of acid on the fracture toughness performance of specimens was reduced by 61 %, 55 % and 13 % for samples containing silica fume, metakaolin and granite sludge at 15% substitution level, respectively. Furthermore, water absorption test results showed that inclusion of silica fume and metakaolin at a substitution level of 15 % results in 56 % and 47 % reduction in water absorption compared to the control specimen, respectively, while for granite sludge, it was almost the same as control specimen. These results were also confirmed by SEM studies. Since the use of these pozzolans as cement substitution not only improves the fracture toughness in normal condition but also provides protection against acid-induced degradation, this study contributes to the development of a more durable and environmentally friendly CEAM.

Synergic effect of polyester fiber and nano silica on chemical resistance of geopolymer mortar.

The aim of this study is to evaluate the synergistic effect of polyester fiber-reinforced and nanoslica on the technical performance and durability of geopolymer mortar in terms of the chemical resistance. The study examined how the addition of polyester fiber and nanosilica affects the short-term severe durability of geopolymer mortar specimens made with fly ash (type F). The specimens were cured under ambient conditions. Different percentages (0.6%, 1.2%, and 1.8%) of polyester fiber were used, both with and without nanosilica. Additionally, a reference mixture containing only nanosilica was prepared.All mixtures had a liquid to binder ratio of 0.50, and the ratio of NaOH to Na2SiO3 solution was kept at 2.5:1 by weight. The produced mixes, after 28 days of ambient curing, were immersed for another 28 days in solutions containing 3.5%, 5%, and 5% of sodium chloride, magnesium sulphate and sulfuric acid, respectively. For comparison, control specimens which were not exposed to chemical attacks were tested at the same age of 56 days. Moreover, water absorption and sorptivity tests were conducted to explain the durability performance in a more detailed way. The test results express that the combination of both materials showed a synergistic effect and resulted in greater improvements in compressive and flexural strengths. Both materials can reduce the reduction in compressive strength caused by sulfuric acid exposure, but polyester fiber can increase mass loss. The presence of magnesium sulfate and sodium chloride can lead to a reduction in strength, but the addition of both polyester fiber and nanosilica can mitigate these effects. The addition of fibers creates a network of pores that can limit water absorption, and nanosilica can further enhance the microstructure and reduce water absorption. However, using polyester fiber beyond 1.2 percent can adversely affect the rate of water absorption.

Comparison of effectiveness of blending and impregnation applications of dispersed nanoparticles on performance of cementitious composites

Blended or impregnated forms of nanomaterials in cementitious composites play a key role in determining mortar performance. In this study, the performance of graphene oxide (GO), silver nanoparticles (AgNPs), pristine multi-wall carbon nanotubes (MWCNTs), and functionalized MWCNTs impregnated and blended cementitious composites were compared using principal component analysis (PCA). The highest recorded compressive strength at 28 days was 39.1 MPa corresponding to the impregnation of carboxylated MWCNTs, representing a 29% improvement compared to reference cementitious composites while blending of pristine MWCNTs achieved a maximum compressive strength of 50.37 MPa, representing a 45% improvement over the reference. The group of GO, low-density AgNPs, and hydroxylated MWCNT-impregnated cementitious composites achieved the best sulfuric acid resistance, with an average compressive strength of 30.15 MPa, water absorption of 21.82%, porosity of 36.29%, and ultrasonic pulse velocity of 2.91 km/s due to preventing harmful sulfate ions entering their structure. After sulfuric acid exposure, a 5% compressive strength decrease occurred due to the presence of the functional groups of GO, hydroxylated MWCNTs, and small, low-density AgNPs on the surface of the cementitious composites. These results show that the impregnation method effectively improves cementitious composites' durability. Using PCA analysis, the pristine MWCNTs-blended cementitious composites were determined as the optimum specimen to obtain a durable mortar both pre- and post-acid exposure.

Chemical Transformations of 2D Kaolinic Clay Mineral Surfaces from Sulfuric Acid Exposure.

A combined experimental and computational approach is used to investigate the chemical transformations of kaolinite and metakaolin surfaces when exposed to sulfuric acid. These clay minerals are hydrated ternary metal oxides and are shown to be susceptible to degradation by loss of Al as the water-soluble salt Al2(SO4)3, due to interactions between H2SO4 and aluminum cations. This degradation process results in a silica-rich interfacial layer on the surfaces of the aluminosilicates, most prominently observed in metakaolin exposed to pH environments of less than 4. Our observations are supported by XPS, ATR-FTIR, and XRD experiments. Concurrently, DFT methodologies are used to probe the interactions between the clay mineral surfaces and H2SO4 as well as other sulfur-containing adsorbates. An analysis performed using a DFT + thermodynamics model shows that the surface transformation processes that lead to the loss of Al and SO4 from metakaolin are favorable at pH below 4; however, such transformations are not favorable for kaolinite, a result that agrees with our experimental efforts. The data obtained from both experimental techniques and computational studies support that the dehydrated surface of metakaolin interacts more strongly with sulfuric acid and provide atomistic insight into the acid-induced transformations of these mineral surfaces.

Assessment of recycled waste fiber and BC soil on the performance of hybrid concrete: reaction and subsequent sulfuric acid exposure

Assessment of recycled waste fiber and BC soil on the performance of hybrid concrete: reaction and subsequent sulfuric acid exposure

Resistance of carbonation-cured belite-rich cement mortar to adverse environments: Magnesium sulfate and sulfuric acid exposure

The present study investigates the potential of carbonation-cured belite-rich cement (BRC) to resist magnesium sulfate (MgSO4) and sulfuric acid (H2SO4) environments. BRC mortar was submerged in 5% and 10% MgSO4 and H2SO4 solutions. The gains of the compressive strength and mass under MgSO4 environment significantly depend upon the buffer (unreacted belite phase) left in the specimen after 28 days of curing. The lowest buffer level, found after 28 days of carbonation curing, stemmed from the higher reactivity of the belite phase as opposed to water curing followed by carbonation curing. Furthermore, degradations in the strength and mass were found in the H2SO4 environment. The presence of the calcium carbonate phase in carbonation-cured BRC mortar increased the acid resistance. An XRD analysis showed sulfate-based mineral phases in the external and core areas of a carbonation-cured BRC mortar cube, representing the higher diffusion efficiency of acid ions than magnesium ions in BRC.

Durability and self-healing of engineered cementitious composites exposed to simulated sewage environments

Corrosion factors including microbiologically induced corrosion accelerate cracking and deteriorations in a sewer concrete pipe especially in regions close to the pipe crown and that near the waterline. Engineered cementitious composites (ECC) is a novel class of ductile cement-based composites and possesses autogenously tight cracks and robust self-healing conducive to sewage environments resistance. This paper presents an experimental study on the durability of ECC exposed to sewage environments simulated by treatments including sulfuric acid exposure and physical erosion. The physical and mechanical properties of ECC were examined in relation to those of fiber-free mortar specimens as control. The objective of this research is to establish fundamental knowledge on the behavior of ECC under aggressive sewage environments. Results showed that the permeable voids increased, and the strength decreased for both ECC and mortar. However, the residual compressive and tensile strength of ECC were 30–65% and 300–370% higher than those of the mortar group after 12 corrosion cycles, respectively. After corrosion cycles, the length change ratio of ECC was about 20% of that of the control, which indicates that ECC has better dimensional stability under the corrosive conditions. Further, self-healing of microcrack damage was observed in ECC under all exposure conditions in this study. It is concluded that ductile ECC has significant advantages in mechanical and durability performance over conventional brittle mortar/concrete under the simulated environments unique in sewage lines. This research generates new data that establish ECC as a durable material for sewer pipeline construction and rehabilitation.

The effect of pozzolanic mineral additives on the strength and durability properties of structural lightweight concrete

Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

Does sulfuric acid have a ‘protective’ effect on battery recyclers exposed to lead?

ABSTRACT Culturally significant interventions to prevent lead exposure of battery recyclers are required. Sulfuric acid used in batteries causes skin lesions and could facilitate the recognition of hazards. This study explored whether joint exposure to lead and sulfuric acid can be used in interventions to manage hazardous work conditions. Data were collected from 120 informal workers, and the blood lead level was measured. Predictors of blood lead levels were explored using a tobit model. The median blood lead level was 9.45 µg/dL (Q75-Q25: 48.9 µg/dL); when lead and sulfuric acid exposure occurred, the level increased to 11.44 µg/dL, and when exposure to lead and other substances occurred, the level was 11.50 µg/dL. Workers are unaware of the risks of obvious and acute silent chronic exposure. Future preventive interventions could confront the economic benefits of battery recycling with the recognition of susceptibility and severity related to lead and sulfuric acid exposure.

Performance of local fly ash geopolymers under different types of acids

A new class of ceramic materials, known as geopolymers, possess comparable or even higher mechanical and chemical properties than ordinary Portland cement-based materials. Because geopolymers can be used in a wide variety of areas, from civil engineering applications to decorative objects manufacturing, they can get in contact with different types of acidic corrosive substances. The degradation degree depends mostly on the acidic solution concentration and the exposure time. Due to the interaction between the geopolymer compounds, Al, Si and Fe ions solubility and the corrosive environment substance, there may follow severe consequences on the material mechanical properties. These consequences are highly related to the geopolymers three-dimensional structure degeopolymerization. The performance of geopolymers under severe environmental condition depends on the raw material, mineralogical composition and activation method. The aim of this paper is to present the effects of nitric acid, sulfuric acid and hydrochloric acid exposure on the local fly ash geopolymers compressive strength and microstructure.

Exposing Sustainable Mortars with Nanosilica, Zinc Stearate, and Ethyl Silicate Coating to Sulfuric Acid Attack

Obtaining durable materials that lengthen the service life of constructions and thereby contribute to sustainability requires research into products that improve the durability of cementitious materials under aggressive conditions. This paper studies the effects of sulfuric acid exposure on four mortar types (control mortar, mortar with nanosilica, mortar with zinc stearate, and mortar with an ethyl silicate coating), and evaluates which of them have better performance against the acid attack. After 28 days of curing, the samples were exposed to a sulfuric acid attack by immersing them in a 3% w/w of H2SO4 solution. Physical changes (mass loss, ultrasonic pulse velocity, open porosity, and water absorption), and mechanical changes (compressive strength) were determined after the sulfuric acid exposure. A scanning electron microscope (SEM) was used to characterize the morphology of the surface mortars after the exposure. The control mortar had the highest compressive strength after the acid attack, although of the four types, the zinc stearate mortar showed the lowest percentage of strength loss. The zinc stearate mortar had the lowest mass loss after the acid exposure; moreover, it had the lowest capillary water absorption coefficient (demonstrating its hydrophobic effect) both in a non-aggressive environment and acid attack.

Response of concrete with blended binders and nanoparticles to sulfuric acid attack

Concrete has long been the most popular material for the construction of key infrastructural elements such as sewerage pipes, water treatment facilities, industrial floors and foundations, which can be chemically vulnerable to damage by sulfuric acid attack. Since high alkalinity is required for stability of the cementitious matrix, concrete is susceptible to attack by acidic media, which may disintegrate the hydrated cement paste to various levels based on the prevailing exposure conditions and key mixture design parameters of concrete. This study investigated the response, in terms of physico-mechanical and microstructural features, of concrete comprising different types of cement (general-use or Portland limestone cement (PLC)) with various combinations of supplementary cementitious materials (fly ash, silica fume and nanosilica) to severe sulfuric acid exposure (immersion of test specimens in 5% sulfuric acid solution with a maximum pH threshold of 2·0 for 90 d). The results revealed that the surface degradation (mass loss) of concrete under severe sulfuric acid attack was independent of its penetrability (physical resistance), since very dense cementitious matrices (low penetrability) suffered severe deterioration. PLC may slightly improve the resistance of concrete to sulfuric acid attack whereas, among the blended binders tested, binary binders comprising 30% fly ash particularly improved the resistance of concrete to sulfuric acid attack due to an inert filler effect of fly ash particles at the exposed surface.

Sustainable approach for recycling waste tire rubber and polyethylene terephthalate (PET) to produce green concrete with resistance against sulfuric acid attack

This work presents a study on the potential use of waste crumb tire rubber and polyethylene terephthalate (PET) particles to produce sustainable concrete. In order to find out the feasibility of such concrete in acidic environment, broad laboratory investigations in terms of crushing load, mass, and ultrasonic wave velocity of tire rubberized concrete (TRC) and tire rubberized PET concrete (TRPC) were conducted and assessed by Taguchi method. Afterwards, the results were compared with normal concrete (NC) and normal PET concrete (NPC). 5, 10, and 15 percent of PET particles along with 15 percent of crumb tire rubber substituted for fine natural aggregate with the aim of reducing the consumption of virgin natural resources and disposing of wastes in a safe, effective, and environmentally friendly approach. The significance levels of the experimental parameters, which indicate how the factors affect the crushing load, mass, and ultrasonic wave velocity, were determined by using Analysis of variance (ANOVA) method. The statistical and analytical results showed that using PET in both NPC and TRPC caused the resistance against sulfuric acid to increase after a 60-day sulfuric acid exposure. Although TRC in comparison to NC had a lower resistance against sulfuric acid, substituting 15 percent of PET particles caused the resistance of TRPC against sulfuric acid to increase significantly and reached that of NPC containing 10 percent of PET. The conclusion is that the waste crumb tire rubber can be employed in concrete in case of using PET particles to compensate for the downside of TRC in acidic environments and, in so doing, a large amount of waste material can be disposed of in a sustainable way.