Waste Gypsum Research Articles

Effect of CaO Sourced from CaCO3 or CaSO4 on Phase Formation and Mineral Composition of Iron-Rich Calcium Sulfoaluminate Clinker.

The performance of iron-rich calcium sulfoaluminate (IR-CSA) cement is greatly affected by mineral composition and mineral activity in the clinker. This study aims to identify the effect of CaO sources, either CaCO3 or CaSO4, on the phase formation and mineral composition of the IR-CSA clinker. Targeted samples were prepared with different proportions of CaCO3 and CaSO4 as CaO sources at 1300 °C for 45 min. Multiple methods were used to identify the mineralogical conditions. The results indicate that the mineral composition and performance of the IR-CSA clinker could be optimized by adjusting the CaO source. Both Al2O3 and Fe2O3 tend to incorporate into C4A3-xFxS¯ with an increase in CaSO4 as a CaO source, which leads to an increased content of C4A3-xFxS¯ but a decreased ferrite phase. In addition, clinkers prepared with CaSO4 as a CaO source showed much higher x value in C4A3-xFxS¯ and higher compressive strength than clinker prepared with CaCO3 as the sole CaO source. The crystal types of both C4A3-xFxS¯ and C2S were also affected, but showed different trends with the transition of the CaO source. The findings provide a possible method to produce IR-CSA cement at a low cost through cooperative utilization of waste gypsum and iron-bearing industrial solid wastes.

Dehydration of gypsum waste to recyclable anhydrite using a nano-film reservoir under ambient conditions

A 39 nm thick sulfuric acid film (NSF) with extremely low water activity was deposited on gypsum particles to enable the phase transformation from gypsum to anhydrite via recrystallization at room temperature.

Effect of binary combination of waste gypsum and fly ash to produce building bricks

South Africa's production of wet flue gas desulfurization (WFGD) gypsum and fly ash (FA) has increased significantly owing to the country's dependence on coal power plant for electricity. These wastes are mainly dumped in landfills, which contributes to environmental pollution. Recycling WFGD gypsum to generate value-added products may benefit the country economically and ecologically. Given the chemical compositions of WFGD gypsum and fly ash, it is feasible to mix them to create a binder material. On the time when the study was done, no evidence of study had been conducted on the binary combination of FA and WFGD gypsum produced locally to create building materials. This study proposes a novel approach to lowering environmental pollution by using two South African wastes, FA and WFGD gypsum, to produce sustainable building materials. The mixture of WFGD gypsum and FA is intended to produce binding phases comprising ettringite and calcium silicate hydrate (CSH). Ettringite can be formed by hydration of alumina (Al2O3) in fly ash with calcium sulfate (CaSO4) and calcium oxide (CaO) of WFGD gypsum, while CSH can be generated by hydration of silica (SiO2) in fly ash under the same conditions. FA was employed moderately to substitute WFGD gypsum in the production of FA: WFGD composite blocks. Composite mixes were produced by substituting 0–40 wt% of WFGD gypsum with FA. Composites bricks obtained were characterized using compression test and wet-dry cycles. Toxicity characteristic leaching procedure (TCLP) were done to determine perilous elements existing in the study sample and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) for morphology analysis. X-ray diffraction (XRD) was utilized to establish the crystallinity of the material. The strength results showed that FA used in this study was poorly reactive. As the partial replacement of WFGD gypsum by FA increased from 0 to 40%, the strength of the composite material decreased. The pessimum effect of FA is mainly related to the low pH of the binary mixture and low pozzolanicity of FA used. Incorporation of 20 wt% FA and curing temperature of 40 °C seemed to be suitable for the preparation of WFGD:FA composite bricks. The composite bricks' highest UCS of 2 MPa exceeded the minimum strength for Class III mortar as per SANS 10145. Therefore, WFGD:FA composite bricks may be used as building materials.

Industrial Waste Management: Economical Benefits of the Resource Utilization of Phosphogypsum

There are many publications in the literature on the reuse of waste gypsum in material production. In this study, in which the analysis of these existing publications is made through the determinations, the data examined are limited to the article and these are not included. However, to understand the general framework of the research in this field better, a few of these in the related literature are given below as examples. It is seen that industrial waste gypsum, which is a type of waste gypsum, has been examined more. Phosphogypsum, which is included in this waste group, reduces the water requirement for adjusting the cement consistency by adding phosphogypsum in cement production. As a result of the addition of phosphogypsum in wall element production, it was determined that the addition of phosphogypsum caused a decrease in mechanical strength, a decrease in unit weight and an increase in water requirement. It has been concluded that the addition of 15% phosphogypsum in soil stabilization of phosphogypsum, which is in the chemical waste class, causes an increase in water demand and pressure strength. In addition, 5.4% gypsum board waste with recycling potential is generated in the production of building elements made with waste gypsum boards formed at a construction site.

Eco-friendly Super Sulphated Cement Concrete Using Vietnam Phosphogypsum and Sodium Carbonate Na2CO3

Sustainable development is one of the critical topics in the construction industry today, especially in reducing CO2 emissions and production energy costs. There have been many studies worldwide on using ground granulated blast furnace slag combined with phosphogypsum (PG) to replace binder (B) in making concrete. However, this topic in Vietnam has not received much attention despite the large backlog of phosphogypsum waste. One of the main disadvantages limiting the feasibility of super-sulphated binders in concrete is the relatively slow hydration and hardening processes, which affect the rate of strength development of mortar and concrete, especially at an early age. In this study, the use of Na2CO3 salt as a quick, solid additive can overcome the disadvantages of this type of binder. Research results show that using 15 to 25% phosphorus gypsum waste (PG) and a combination of 60 to 80% finely granulated blast furnace slag (GGBFS) with a small amount of cement and an activator like Na2CO3can replace cement in making concrete. The concrete mix has good workability, and the maximum compressive strength after 28 days can reach over 50 MPa. Using industrial wastes as the main ingredients to make binders will improve sustainable development, reducing environmental pollution and the cost of mortar and concrete products in construction. Doi: 10.28991/CEJ-2022-08-11-06 Full Text: PDF

Utilization of flue gas desulfurization gypsum waste as a partial substitution of cement for the production of concrete bricks

This research aims to determine the use of flue gas desulfurization gypsum waste as a partial substitution of cement for the manufacture of concrete bricks. Flue gas desulfurization gypsum is waste from the tin processing that takes place. This research uses flue gas desulfurization gypsum waste compositions of 5%, 15%, 25%, and 35% by weight of cement. The design of the concrete brick was mixed with a design compressive strength value of 5 MPa and is included in the class II quality category according to SNI 03-0349-1989 concerning concrete bricks for masonry walls with a water-cement factor value of 0,4. The size of the test object is 40 x 10 x 20 cm, where the making of concrete brick uses a hydraulic press machine with a total sample of 40 pieces. The results showed that the use of flue gas desulfurization gypsum could increase the compressive strength with a substitution percentage of 5% with an optimum average compressive strength value of 8,569 MPa and the optimum water absorption value with a 5% substitution percentage of 9,315%. The percentage above 5% experienced a decrease in the average compressive strength and an increase in the average water absorption capacity of the concrete bricks.

Environmental risk assessment of industrial byproduct gypsum utilized for filling abandoned mines

In response to the basic policy of green and low-carbon circular development to solve resource, environmental and ecological problems, gypsum is considered to be a filling material for mine backfilling. To explore the potential risks of gypsum to the groundwater environment due to the backfilling of abandoned mines, a sequential batch leaching experiment was carried out in this paper, which used three types of industrial waste gypsum, namely, phosphorus gypsum (PG), titanium gypsum (TG) and flue gas desulfurization gypsum (FGDG). COMSOL Multiphysics 5.4 software was used to simulate and solve the migration process of the leached metal elements in the mine floor when these three gypsum types were used as filling materials to observe the concentration distributions and diffusion distances of the metal elements from these three gypsum types in the mine floor. The results show that (1) during repeated contact of the three types of industrial waste gypsum with the leaching medium, the pH levels changed, and the changes in pH affected the leaching patterns for the heavy metal elements in the gypsum. (2) Based on the concentrations of the metal elements that were leached from the three types of gypsum, it can be determined that these three types of gypsum are not classified as hazardous solid wastes, but they cannot be ruled out with regard to their risk to the groundwater environment when they are used as mine filling materials. (3) When the three types of gypsum are used as filling materials, the concentration distributions of the metal elements and their migration distances all exhibit significant changes over time. The concentration distributions, diffusion rates and migration distances of the metal elements from the different gypsum types are affected by their initial concentrations in the leachate. The maximum migration distances of Zn in the floor from the PG, FGDG and TG are 8.2, 8.1 and 7.5 m, respectively.

Effect of Gypsum Waste Inclusion on Gasification of Municipal Solid Waste

Abstract Sustainable disposal techniques of municipal solid wastes (MSW) are essential for effective materials recovery and energy management. Synergistic incorporation of gypsum waste from the construction and demolition (C&D) sector is explored here for the low techno-economic viability of MSW in waste-to-energy facilities. Co-processing of MSW with this low-value gypsum can potentially provide improved product recovery and simultaneously furnish economic viability. To understand the impact of gypsum incorporation into MSW conversion, we tested synthetic MSW and a 1:1 mixture of MSW with gypsum from drywall wastes and compared their micro-scale mass loss kinetics along with macro-scale syngas evolution and conversion at different temperatures, and in pyrolytic and oxidizing environments. Gypsum incorporation led to increased syngas production and decreased char yields as the char was oxidized by CaSO4. Thermogravimetric analysis (TGA) revealed two different temperature zones of gypsum interaction with MSW depending on the oxidation concentration in the environment. Adding 50% gypsum only changed the final ash yield by 10% in pyrolysis conditions suggesting the viability of gypsum incorporation. While the addition of gypsum led to delayed evolution of H2 and CO, the cumulative yields of H2 and CO2 increased significantly and the yield of CO changed minimally. Additionally, hydrocarbon by-products such as CH4 decreased by gypsum addition. The results showed improved syngas yield and uniformity, as well as operational conditions from the gypsum interaction with MSW which can help in the further development of gypsum waste incorporation.

Two-stage cyclic ammonium sulfate roasting and leaching of extracting vanadium and titanium from vanadium slag

Compared with traditional sodium or calcification roasting process for vanadium extraction from raw vanadium slag (V-slag), ammonium sulfate (AS) roasting could reduce about 470 °C roasting temperature and avoid Cl2, HCl, sodium-containing waste-water and waste gypsum discharging. To reduce the amount of AS added in vanadium extraction process, an efficient AS two-stage cyclic roasting and acid leaching process was proposed. The result of TG analysis indicates V-slag could be decomposed in 275–380 °C using AS roasting process. Using 2.03:1 total mass ratio of AS to V-slag, 90.86% V and 80.54% Ti could be extracted after 380 °C roasting for 30 min and 8% initial concentration of H2SO4 leaching at 70 °C for 100 min. XRD analysis indicates V-containing spinel phase in the 1st stage leaching residue would be efficiently decomposed by the cyclic two-stage roasting and leaching process. Furthermore, the valence of V(III) in raw V-slag was not changed after the 1st AS roasting stage, but a part of V(III) in the 1st leaching residue was oxidized to V(V) after 2nd roasting process.

Pengaruh Sandblasting Dan Limbah Gypsum Sebagai Bahan Campuran Beton

Normal concrete is concrete with a compressive strength value of 15-40 MPa.this study aims to find out the workability of fresh concrete with the addition of sandblasting 10% and gypsum waste variations of 0%, 2%, 4%, 6% in concrete mixtures. Samples with a cylindrical shape with dimensions of 15cm x 30cm total 12 pieces, as well as beams with dimensions of 15cm x 15cm x 60cm total of 3 pieces. In the strong press test process obtained numbers 26,020, 24,027, 23,469 and 21,161 Mpa. Testing tensile strengths of 2,712, 2,098, 1,745, and 1,462 Mpa. Tests of 4,119, 3,793, 3,585, and 3,230 MPa. Elasticity modulus testing of 22384, 20497, 20025, and 19132 MPa. The results showed that gypsum waste cannot be used as a concrete quality mixture material.

Durabilitas Campuran Stone Matrix Asphalt Kasar Menggunakan Limbah Gypsum Sebagai Substitusi Filler

In fact, most of the construction of road pavement layers is damaged due to rainwater puddles. This study was intended to determine the durability of the Coarse Stone Matrix Asphalt mixture using gypsum waste as a filler substitution. The results of research, through the marshall immersion test with the proportion of gypsum waste as a cement filler substitution, namely 25%: 75% with 6% asphalt content and variations in immersion time, namely 12 hours, 24 hours. 36 hours, 48 hours, and 60 hours. The test results for the Coarse Asphalt Stone Matrix mixture obtained durability between 97.99% - 92.31%. The relative durability value decreases with increasing immersion time, due to a large number of cavities or pores of the mixture filled with water so that the mixture is easily damaged.

Sanitary Ware Waste as a Source for a Valuable Biodiesel Catalyst

Biofuel is a type of fuel that is made from biomass using modern techniques rather than the relatively slow geological processes that lead to the development of fossil fuels. In Europe, biodiesel is the most widely used biofuel. The sanitary ware industry generates a lot of hazardous waste, such as waste gypsum molds. These molds are broken, pulverized, and reacted with NaCO3 to make CaCO3, which is then heated to produce CaO. The resulting CaO catalyzes the reaction between waste frying oil and methanol for biodiesel synthesis. To evaluate the effect of reaction parameters on the production of biodiesel, the independent reaction parameters that were chosen are as follows: reaction temperature in the range 50–70°C, methanol to oil (M:O) molar ratio in the range 9–15, catalyst loading in the range 1–5%, and time in the range 2–6 hrs. The influence of the independent factors on the reaction-dependent responses was evaluated and it was found that reaction temperature and methanol-to-oil ratio have a major effect on the biodiesel yield. Reaction condition optimization has been studied to maximize biodiesel yield at minimum reaction conditions. The optimum process conditions are 93.4% biodiesel yield at an M:O molar ratio of 15 : 1, catalyst loading of 1%, reaction temperature of 53.6°C, and reaction time of 2 h. The results showed that resulted biodiesel catalyst (CaO) can be used one time; then, a fresh catalyst will be used.

Evaluation of physical properties of autoclave aerated concrete (AAC) based glass-gypsum waste into concrete

The world produces billions of tonnes of Municipal Solid Waste (MSW) yearly, with part of it not being properly disposed of. To approach sustainable development and reduce waste in landfills, using waste in material production is proposed. According to the World Green Building Council, construction projects have expanded and demand for green buildings is likely to increase in the next three years. Autoclaved Aerated Concrete (AAC) is considered an environmentally friendly product compared to standard concrete and bricks. This paper aims to investigate the influence of glass waste (GW) and gypsum wastes as additional materials on the physical properties and compressive strength of AAC is to determine the optimum proportion of GW addition to produce AAC based glass-gypsum waste (AAC-GGW) and to compare the properties of AAC-GGW with the reference sample. The materials used were Ordinary Portland Cement (OPC), quartz sand, lime, aluminum paste, GW, and gypsum waste. The ratios of all materials were kept constant except GW with increment of 0%, 5%, 10%, 15%, 20%, 25% and 30%. The density, water absorption, porosity, and average compressive strength of the samples were measured and compared. It was found that increasing GW increased the samples’ density and decreased the samples’ water absorption and porosity. It was also found that the addition of GW from 5% to 25% achieved better average compressive strength than the reference sample with no addition of GW. Maximum compressive strength was achieved at 20% GW addition.

Recycling of Industrial Waste Gypsum Using Mineral Carbonation

Direct mineral carbonation (MC) is used to mitigate carbon dioxide (CO2) emissions. This method has the great advantages of reducing the amount of industrial residues and creating valuable materials by incorporating CO2. Waste gypsum, industrial waste including flue gas desulfurization (FGD) gypsum (25.27–53.40 wt% of CaO), and phosphogypsum (30.50–39.06 wt% of CaO) can be used for direct MC (conversion rate up to 96%). Mineral carbonation converts waste gypsum into calcium carbonate (CaCO3), which can be recycled during desulfurization. Furthermore, ammonium sulfate ((NH4)2SO4), which is used as a fertilizer, can be prepared as a by-product when the carbonation reaction is performed using ammonia (NH3) as a base. In this study, recent progress in the carbonation kinetics and preparation of CaCO3 using FGD gypsum and phosphogypsum with NH3 was investigated. Temperature, CO2 partial pressure, CO2 flow rate, and NH3 concentration were reviewed as factors affecting carbonation kinetics and efficiency. The factors influencing the polymorphs of the prepared CaCO3 were also reviewed and summarized. A state-of-the-art bench-scale plant study was also proposed. In addition, economic feasibility was investigated based on a bench-scale study to analyze the future applicability of this technology.

Strength development and microstructure of recycled gypsum-soda residue-GGBS based geopolymer

The utilization of waste materials in road construction is one type of sustainable infrastructure practice, which reduces the dependence on natural resources. The waste, including recycled gypsum powder (from construction and demolition waste), soda residue (from the Na2CO3 industry), and ground granulated blast-furnace slag (GGBS), are favorable supplementary cementitious materials. This paper aims to evaluate the recycled potential of gypsum waste and wet-basis soda residue combined with GGBS to prepare geopolymer for subgrade applications. In this regard, the geopolymer mixture containing 0%, 5%, 10% recycled gypsum and 60%, 70%, 80% soda residue by dry weight will be prepared as partly substitute for GGBS. The mechanical performance will be measured using unconfined compression strength (UCS) and studied strength mechanism via scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Test results reveal that the strength of the RG-SR-GGBS based geopolymer decreased with increasing SR dosage and increased with increasing curing age. Excessive dosing of 10% recycled gypsum as a partial substitute for GGBS was detrimental to the strength of geopolymer, while a 5% dose was beneficial to increase the UCS value. The geopolymer of group SR60-RG5-S35 achieved a maximum UCS value of 9310 kPa at the curing age of 28 days. Ettringite (AFt) is a stable hydration product only if there is a sufficient supply of sulphate from recycled gypsum. Many rod-like AFt crystals form cavities in the geopolymer thus reducing the UCS value, while the right amount of AFt fills the capillary pores and increases the structural density and strength. GGBS was activated by the alkalinity of soda residue to generate dense calcium silicate hydrate (C-S-H gel), which is the main reason for the strength development.

Enhancement of phosphogypsum mechanical block with the addition of iron and aluminum salts

Waste gypsum is one of the typical industrial solid waste in the world. Due to its treatment technical barriers, the existing treatment of waste gypsum is mainly stockpiled. And with the rapid development of industry, the treatment of waste gypsum has become one of the key issues of environmental protection. In this study, blocks of phosphogypsum were pressed by conventional mechanical methods, and subsequently, the effects of different pressing press pressures, curing times, moisture content and different added substances on the mechanical and waterproof properties of the block were investigated. The experimental results showed that when the pressing pressure is 300 MPa, curing time is 3 d, water content is 5%, and the content of elemental iron and aluminum is 1%, the mechanical properties and waterproof performance are the best. At this time, the compressive strength is 54 MPa, the flexural strength is 8 MPa, and the softening coefficient is more than 0.90. Through the leaching toxicity analysis, it was found that the pressed block has a better sealing effect on the toxic and harmful substances in the waste gypsum, and the toxic and harmful substances were not be released. This method provides an economic and simple way for high value-added resource treatment of solid waste gypsum.

Improvement mechanism of water resistance and volume stability of magnesium oxychloride cement: A comparison study on the influences of various gypsum

The development of magnesium oxychloride cement can effectively utilize the waste of potash industry and reduce its harm to the environment. Although magnesium oxychloride cement paste (MOCP) has excellent performance in dry environment, its performance is greatly deteriorated in water or humid environment, which severely limits its practical application. In order to improve the water resistance of MOCP, MOCP was modified by various gypsum in this study, and the intrinsic mechanism was explored. Results showed that replacing MgO with gypsum delayed the setting time of MOCP and effectively improved its volume stability. Although the incorporation of gypsum reduced the 14-d air-cured compressive strength of MOCP, waste gypsum was able to significantly improve the water resistance of MOCP compared to natural gypsum. When 80% flue gas desulfurization gypsum and phosphogypsum (weight of magnesium oxide) were incorporated into MOCP, the 14-d air-cured compressive strength of MOCP was only decreased by 14.49% and 15.94% compared with the control group, but its 28-d water immersion strength retention coefficient (SRC) could still reach 61.02% and 46.55%, respectively. However, for the control group and MOCP with 80% natural gypsum, the 28-d SRC were only 28.99% and 8.41%. The incorporation of high-volume waste gypsum to MOCP not only reduced the relative content of MgO, but also improved the stability of the 5-phase in water, which was beneficial to improve the water resistance of MOCP. In addition, high-volume waste gypsum-modified MOCP had lower cost and carbon emissions, and exhibited superior water resistance and sustainability compared to existing MOCP compositions.

불소 오염토양의 기원별 오염특성을 파악하기 위한 광물학적 특성분석 및 세척효율평가

In this study, mineralogical characteristics analysis and extraction characteristics evaluation were performed to identify the contamination characteristics by origin of fluoride-contaminated samples of natural origin by granite mica and artificial fluoride-contaminated samples by waste gypsum fluoride of making fertilizer process. In samples of natural origin, mica, quartz, feldspar, fluorite, and amphibole showed the high mineral content in the order. Among them, mica, which is expected to be the causative mineral of fluorine contamination, consisted of muscovite, biotite, and lithium mica. In artificial fluoride-contaminated samples, quartz, plagioclase, illite, gypsum, sulfur, and wollastonite showed the highest mineral content in the order. Compared to the total mica content and fluorine concentration of the natural origin contaminated sample, a proportional linear relationship(R2=0.68) was shown, and this result is estimated to be the influence of natural origin by minerals in badlock not artificial contamination. When compared with the gypsum content and fluorine concentration of the artificially contaminated samples, a proportional linear relationship(R2=0.79) was shown, and the fluoride concentration was found to exceed the standard in all samples with a gypsum content of about 20 % or more. As a result of the washing efficiency test for each mica fluoride-contaminated sample, it was confirmed that the washing efficiency was relatively low with all washing agents less than 10 %, and hydrochloric acid(HCl) had the highest washing efficiency. In addition, the optimal hydrochloric acid(HCl) concentration was confirmed to be 1 M. As a result of the washing efficiency test for each washing agent for the fluorine-contaminated sample of a fertilizer factory, sodium hydroxide(NaOH) was confirmed to have the highest washing efficiency and showed about 1.5 times higher than hydrochloric acid(HCl). In addition, the optimal concentration of sodium hydroxide(NaOH) is judged to be suitable at 0.5 M, which showed a washing efficiency of 65.6 %. Based on the results of this study, it is intended to be used as a basic data for the development of soil remediation technology considering the method of proving the cause of fluoride-contaminated soil and the characteristics of contamination by origin.

A critical evaluation of the chlorine quantification method based on molecular emission detection in LIBS

The entire process involving the determination of Cl by molecular emission detection in Laser-Induced Breakdown Spectroscopy (LIBS) is thoroughly studied in this paper. This critical evaluation considers how spectra are normalized, how interferences from other molecular species signals are removed, and how signal integration is applied. Moreover, a data treatment protocol is proposed to achieve reliable and accurate Cl determination from the CaCl molecular spectral signal, not requiring the use of more complex numerical approaches. Calcium chloride dihydrate (CaCl2·2H2O) and high purity anhydrite samples (CaSO4) are used to optimize the acquisition conditions and data treatment of CaCl emission signal. Using the developed protocol, calibration curves for Cl, covering the concentration range from 0 μg/g to 60,000 μg/g of Cl, are successfully achieved. Finally, the suitability of the proposed methodology for Cl determination is successfully applied in industrial gypsum waste samples, where the results obtained by LIBS are validated using high-resolution molecular absorption spectroscopy (HR-CS-MAS) and potentiometric titration.

Study on UV resistance of high density polyethylene composite using waste gypsum

Every year, a large amount of waste gypsum, a by-product of fertilizer production, was produced and landfilled that increasing the harm to the environment. In this study, for the purpose of utilizing waste gypsum, it was studied as the filler in blend of high density polyethylene (HDPE) and ethyelene vinyl acetated (EVA) with anti UV additives in order to improve the mechanical strength and lifespan of this composite. After using ethylene bis stearamide (EBS) to modify waste gypsum, modified waste gypsum (mGyp) and anti-UV additives at various contents were dispersed into HDPE/EVA blend by melt-mixing method to obtain HDPE/EVA/mGyp composites. As the results, the color difference and tensile strength of composite using additives did not changed much after 20 cycles of accelerated weathering test. In the presence of anti-UV additives, the photodegradation process was inhibited by showing the low carbonyl index of composite compared with samples without additives. Beside, the structure of composite using anti-UV additives is smooth and without cracks after accelerated weathering test as observed in SEM images. That led to the tensile strength of sample did not change much.