Microsoft Word - ETASR_V12_N6_pp9426-9430 Engineering, Technology & Applied Science Research Vol. 12, No. 6, 2022, 9426-9430 9426 www.etasr.com Mohammed & Al-Hadithi: The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer… The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer-Modified Mortar Zainab Essam Mohamed Department of Civil Engineering University of Baghdad Baghdad, Iraq zainab.mohammed2001m@coeng.iobaghdad.edu.iq Abdulkader Ismail Al-Hadithi Department of Civil Engineering University of Anbar Ramadi, Iraq abdulakder.alhadithi@uoanbar.edu.iq Received: 26 July 2022 | Revised: 10 August 2022 | Accepted: 11 August 2022 Abstract-This study assessed the efficiency of Expanded Polystyrene (EPS) waste as a 10, 20, 30, 40, 50, and 60% substitute for fine aggregate in the manufacturing of lightweight cement composites. A 4% low-cost latex paint emulsion was added to the cement mortar to reinforce it as an alternative to the more expensive polymer admixtures. This improved the bonding between the cement matrix and the EPS particles because SBR films were produced in the cement matrix. The flexural strength of regular EPS concrete may also be significantly increased by SBR treatment. Eight alternative mix designs were created and evaluated for compressive and flexural strength, thermal conductivity, water absorption, and dry density. The polymer- modified mortar was created using a 0.4 water/cement ratio of local cement, polymer, and polystyrene. The results showed that compared to the standard combination at 28 days of aging, the compressive strength increased up to 29.26Mpa, flexural strength increased to 6.83Mpa, dry density increased up to 1930kg/m³, and absorption decreased by 4.95. Thermal conductivity decreased by 0.8291W/m.k. Keywords-Polymer Modified Mortar (PMM); polymer; polystyrene; compressive strength I. INTRODUCTION Chemically or steam-processed polystyrene foam components are heated at high temperatures to produce Expanded Polystyrene (EPS), a Lightweight Artificial Aggregate (LWA). Round, closed-cell polystyrene particles have a density between 20 and 35kg/m³ and are composed of 98% air [1, 2]. Sandwich panels, floor decks, and curtain walls with increased thermal and acoustic insulation often use these lightweight nonstructural components. [2]. Environmentally friendly and inexpensive sound materials are becoming more popular. EPS is often used in packaging with minimum absorption and low cost because of its low density, hydrophobic characteristics, and excellent thermal insulation. Globally, an estimated amount of 14 million metric tons of polystyrene are manufactured each year and a large portion of the produced waste is placed in landfills [3, 4]. Styrene Butadiene Rubber (SBR) latexes may reduce bleeding and segregation in the cementitious matrix [5]. The network and the filler are two distinct parts of a polymeric composite. The dispersed stage and fortification are other names for this stage. The disseminated media is responsible for further structural progress. The goal is to better connect the matrix to the filling [6] Polymer-Modified Mortar (PMM). With the right mix of cement and latex, PMM is an ideal product for use in the construction industry. Concrete and mortar characteristics may be altered by polymers. This material has higher tensile strength, improved chemical resistance, long-term use, and less environmental impact [7]. Latex improves the adhesive or bonding strength of materials such as pastes, mortars, concretes, tiles, bricks, steel, wood, and stone compared to the industry's unaltered counterparts [8]. Instead of cement, SBR is used in civil engineering to improve the hardened properties of concrete [9]. Adding SBR to strong concrete alters its physical properties. SBR is the most often used cement mortar modifier. The resulting cement hydrate and polymer layer have excellent adhesion properties. This results in less deformation and a more excellent crushing and flexural strength than conventional concrete [10]. SBR latex is widely used in a variety of modified solutions to enhance impermeability and frost resistance. SBR latex has often been used to repair reinforced concrete structures. Several studies found that adding SBR latex to cement mortar increased bonding and flexural and tensile strength. This study attempts to improve the bonding between EPS particles and cement paste by including SBR latex in EPS concrete mixtures, improving compressive strength, flexural strength, thermal conductivity, and water absorption. II. MATERIAL CHARACTERIZATION A. Cement This study used OPC Cement I 42.5N. Tables I and II show its chemical and physical characteristics, which are in accordance with Iraq's specification No. 5/2019 [11]. B. Fine Aggregates The used fine aggregates met the criteria in [12], had excellent gradation, were free of dangerous chemicals that might affect the examination's findings, went through the 0.6mm sieve, and passed the sieving test. Corresponding author: Zainab Essam Mohammed Engineering, Technology & Applied Science Research Vol. 12, No. 6, 2022, 9426-9430 9427 www.etasr.com Mohammed & Al-Hadithi: The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer… C. Water According to [13], the utilized water was pure and devoid of contaminants. D. Polymer The SBR polymer was utilized without any treatment to make the Polymer Cement Mortar (PCM) mixes. Table III lists the SBR polymer's physical characteristics. E. Expanded Polystyrene Beads This study used spherical EPS beads with a maximum nominal size of 5mm instead of fine aggregates in certain instances. Table IV shows the physical characteristics of the EPS beads and the particle size gradient discovered during the EPS sieve analysis. Figure 1 shows the prepared EPS beads in a spherical shape. TABLE I. CEMENT'S CHEMICAL COMPONENTS Oxide composition Result Limits of [12] CaO 62 - SiO2 20.1 - Al2O3 4.24 - Fe2O3 4.16 - SO3 2.15 ≤ 2.8% if C3A>3.5 ≤ 2.5% if C3A<3.5 MgO 3.65 ≤ 5% Loss on ignition 3.42 ≤ 4% Insoluble residue 0.71 ≤ 1.5% Cement compounds [24] C3S 59.02 C2S 29.65 C3A 4.21 C4AF 12.65 TABLE II. PHYSICAL PROPERTIES OF CEMENT Physical properties Test result Limits of [12] Specific surface area, Blaine method, (m²/kg). 295 ≥ 250 m 2 /kg Setting time -Initial setting (min) -Final setting (min) 1:38 3:45 ≥ 45 min ≤ 600 min Compressive strength of mortar (MPa) 2-days 28-days 20.4 27.5 ≥ 10 N/m 2 ≥ 42.5 N/m 2 Soundness % (autoclave) 0.35 ≤ 0.8 TABLE III. PHYSICAL PROPERTIES OF SBR POLYMER Specifications given by the company Appearance Milky white Specific Gravity 1.02 ± 0.2 @ 250 o C Chloride content Nil (EN 934-2) PH value 7 - 10.5 TABLE IV. CHEMICAL AND PHYSICAL PROPERTIES OF EPS Sieve size Passing% ASTM C 330 4.75mm 6.5 5–40 2.36mm 1.5 0–20 Physical properties SO3% – Specific gravity – Absorption 0 Maximum particle size 5 Fig. 1. Expanded polystyrene beads. III. EXPERIMENTAL WORK A. Mixing An electric mechanical mixer with a capacity of 0.1m 3 was used. Cement and fine aggregates were first added to the mixer and stirred for 1min. Following the proper dilution with water, the SBR polymer dispersion was added and mixed for around 3min at low speed. Finally, the other EPS particles were blended with the initial materials for an additional two minutes. Due to their low density, compared to other ingredients in the combination, this was done to guarantee that the polystyrene granules would not volatilize. The remaining water was added to the components that had already been mixed slowly and steadily for another 3 to 5min to get a homogeneous mixture free of segregation. Table V displays the percentages of the materials utilized in this production. TABLE V. DETAILS OF MIXTURE PROPORTIONS Mix C:S W/C% Polymer:cement% EPS% Flow (mm) E1 1:3 0.58 0% 0% 85 E2 1:3 0.4 4% 0% 100 E3 1:3 0.4 4% 10% 145 E4 1:3 0.4 4% 20% 147 E5 1:3 0.4 4% 30% 150 E6 1:3 0.4 4% 40% 155 E7 1:3 0.4 4% 50% 165 E8 1:3 0.4 4% 60% 190 B. Casting, Compaction, and Curing Metal sheets were placed on top of the molds to prevent the samples from evaporating while remaining in the molds for 24h. This is the most effective way to cure polymer-containing concrete [14]. After being soaked in water for 72h, the samples were removed from the molds and left to dry until evaluation. The total number of samples prepared in this study was 168. IV. RESULTS AND DISCUSSION A. Flow Test Figures 2 and 3 illustrate how an increase in replacement% helped boost the flow for EPS samples [15], validating that the hydrophobic properties of EPS aggregates were the higher value of the cause of the flow test. The natural aggregates exhibited angular shapes, while EPS particles were spherical. Therefore, more EPS causes more lubrication between the particles, which reduces friction and increases the flow test [16]. Engineering, Technology & Applied Science Research Vol. 12, No. 6, 2022, 9426-9430 9428 www.etasr.com Mohammed & Al-Hadithi: The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer… Fig. 2. Flow and effect relationship of EPS and SBR addition. Fig. 3. Flow test. B. Compressive Strength This test was conducted using cubic specimens 50×50×50mm in size [17]. The test ages were 3, 7, and 28 days, and 3 cubes were examined for each age. The SBR concrete without EPS had the maximum compressive strength (up to 42.6MPa), surpassing the benchmark mix. In terms of combinations, the percentages of EPS by weight of fine aggregates were 10, 20, 30, 40, 50, and 60%. Adding more polystyrene, the inadequate film formation caused a considerable reduction in the compressive strength of the polymer EPS concretes. The greatest compressive strength value was found for the 10% polystyrene replacement ratio (up to 29.26MPa), as shown in Figures 4 and 5. Compressive strength dropped as the percentage of polystyrene increased [18]. Fig. 4. Relationship of compressive strength and EPS. Fig. 5. Testing cubic concrete sample. C. Flexural Strength Flexural strength determines how materials react to simple beam loads [19]. This test employed dimensional prismatic specimens (40×40×160mm) with various curing ages (7, 14, and 28 days). Three prisms were examined for each age. Figures 6 and 7 show the results. Figure 6 shows that the sample with a 10% substitution with EPS had flexural strength values that were greater than the standard, and even greater than the values of the SBR 4% mixing container. As the EPS ratio decreased, the flexural strength increased. An increase in flexural strength was accompanied by a rise in density because polymeric coatings increased the flexural strength of cured concrete [20]. Fig. 6. Relationship between flexural strength and EPS. Fig. 7. Testing a prismatic concrete sample. D. Thermal Conductivity Cylinders measuring 100×200mm were produced to measure thermal conductivity [21]. The test was carried out at 28 days of age on 3 samples for each age. Thermal conductivity and density were shown to be closely related. Figures 8 and 9 show that thermal conductivity decreased when density declined. Porosity increased with EPS levels, which resulted in a reduction in heat conductivity. Adding SBR to the combinations had a considerable negative impact on thermal conductivity. The findings demonstrate that the density and volume of EPS impacted the thermal conductivity of the concrete. The partial replacement of fine aggregate with EPS was responsible for the change brought about in the lower density and greater air spaces of EPS beads, which resulted in the reduction of thermal conductivity outcomes of mixtures [22]. E. Water Absorption The beads were hydrophobic because they were made of polystyrene sulfonate EPS. Figure 10 shows that the results of the absorption test worsened as EPS content increased. With increased EPS particles, mortars become more porous internally, making it easier for water to enter the mortar [23]. Engineering, Technology & Applied Science Research Vol. 12, No. 6, 2022, 9426-9430 9429 www.etasr.com Mohammed & Al-Hadithi: The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer… Fig. 8. Relationship between thermal conductivity and density. Fig. 9. Testing a cylinder concrete sample. Fig. 10. Relationship between absorption (%) and EPS. V. CONCLUSION The evaluation of thermal conductivity, flexural strength, and compressive strength of polymer-modified mortar and expanded polystyrene beads led to the following conclusions:  At 28 days, the reference mixture's compressive strength at 10% replacement increased by 5.46%. Systematic reductions were made when the use of EPS use increased.  At 28 days, the 10% replacement attained the greatest flexural strength of 6.83MPa.  SBR enhanced overall porosity, decreased density, and created artificial micropores. Because of this, the partial substitution of aggregate with EPS may be blamed for the lower thermal conductivity. The material's insulating quality also increased due to the samples' decreased thermal conductivity.  EPS demonstrated a successful use as a substitute material in the construction of nonstructural elements. It also provided a solution to the disposal of expanded polystyrene waste. Concrete's density and compressive strength decreased as the proportion of EPS substitute increased. The 10% EPS was best suited for non-structural uses, such as wall building and ornamental moldings. However, since it tends to break quickly under strain, 30, 40, 50, and 60% replacement should not be utilized for non-structural reasons. Therefore, it is advised to include polystyrene in concrete mixtures when low-density (lightweight) concrete is desired and resistance is unnecessary.  At 28 days, the 10% EPS replacement combination's water absorption was 4.95% lower than the reference mixture. REFERENCES [1] K. N. Lakshmikandhan, B. S. Harshavardhan, J. Prabakar, and S. Saibabu, "Investigation on Wall Panel Sandwiched With Lightweight Concrete," IOP Conference Series: Materials Science and Engineering, vol. 225, Dec. 2017, Art. no. 012275, https://doi.org/10.1088/1757- 899X/225/1/012275. [2] J. Assaad, E. Chakar, and G.-P. Zéhil, "Testing and modeling the behavior of sandwich lightweight panels against wind and seismic loads," Engineering Structures, vol. 175, pp. 457–466, Nov. 2018, https://doi.org/10.1016/j.engstruct.2018.08.041. [3] S. H. Soomro et al., "Synthesis and Characterization of Poly(styrene)- block-Poly(acrylic acid) and Organoclay Based Hybrid Composite Materials," Engineering, Technology & Applied Science Research, vol. 8, no. 5, pp. 3411–3415, Oct. 2018, https://doi.org/10.48084/etasr.2273. [4] N. A. Memon, A. H. Larik, M. A. Bhutto, N. A. Lakho, M. A. Memon, and A. N. Memon, "Effect of Prepackaged Polymer on Compressive, Tensile and Flexural Strength of Mortar," Engineering, Technology & Applied Science Research, vol. 8, no. 3, pp. 3044–3047, Jun. 2018, https://doi.org/10.48084/etasr.2039. [5] J. J. Assaad and N. Gerges, "Styrene-butadiene rubber modified cementitious grouts for embedding anchors in humid environments," Tunnelling and Underground Space Technology, vol. 84, pp. 317–325, Feb. 2019, https://doi.org/10.1016/j.tust.2018.11.035. [6] D. K. Bangwar, M. A. Soomro, N. A. Laghari, M. A. Soomro, and A. A. Buriro, "Improving the Bond Strength of Rice Husk Ash Concrete by Incorporating Polymer: A New Approach," Engineering, Technology & Applied Science Research, vol. 8, no. 1, pp. 2595–2597, Feb. 2018, https://doi.org/10.48084/etasr.1791. [7] B. A. Herki and J. M. Khatib, "Valorisation of waste expanded polystyrene in concrete using a novel recycling technique," European Journal of Environmental and Civil Engineering, vol. 21, no. 11, pp. 1384–1402, Nov. 2017, https://doi.org/10.1080/19648189.2016. 1170729. [8] J. M. Khatib, B. A. Herki, and A. Elkordi, "7 - Characteristics of concrete containing EPS," in Use of Recycled Plastics in Eco-efficient Concrete, F. Pacheco-Torgal, J. Khatib, F. Colangelo, and R. Tuladhar, Eds. Woodhead Publishing, 2019, pp. 137–165. [9] Y. Ohama, "Polymer-based admixtures," Cement and Concrete Composites, vol. 20, no. 2, pp. 189–212, Jan. 1998, https://doi.org/ 10.1016/S0958-9465(97)00065-6. [10] K. K. Kim, J. Yeon, H. J. Lee, and K.-S. Yeon, "Feasibility Study of SBR-Modified Cementitious Mixtures for Use as 3D Additive Construction Materials," Polymers, vol. 11, no. 8, Aug. 2019, Art. no. 1321, https://doi.org/10.3390/polym11081321. [11] "Iraqi Standard No. 5: Portland Cement. Standardization and Quality Control Central Organization," Baghdad, Iraq, 2019. [12] "Iraqi Specification No. 45: Aggregates of Natural Resources Used in Concrete and Construction in Iraq," Baghdad, Iraq, 1984. [13] "Iraqi Specification No .1703: Water Used for Concrete and Mortar," Baghdad, Iraq: Central Organization for Standardization and Quality Control, Baghdad, Iraq 1992. [14] "Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory," ASTM, West Conshohocken, PA, US, Standard C 192/C 192M-02. [15] "Standard Test Method for Flow of Hydraulic Cement Mortar," ASTM, West Conshohocken, PA, US, Standard C1437-20, 2001. [16] N. Hilal, N. Hamah Sor, and R. H. Faraj, "Development of eco-efficient lightweight self-compacting concrete with high volume of recycled EPS waste materials," Environmental Science and Pollution Research, vol. 28, no. 36, pp. 50028–50051, Sep. 2021, https://doi.org/10.1007/s11356- 021-14213-w. Engineering, Technology & Applied Science Research Vol. 12, No. 6, 2022, 9426-9430 9430 www.etasr.com Mohammed & Al-Hadithi: The Effect of Adding Expanded Polystyrene Beads (EPS) on Polymer… [17] "Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens)," ASTM, West Conshohocken, PA, US, Standard C109/C109M-20. [18] T. K. M. Ali, N. Hilal, R. H. Faraj, and A. I. Al-Hadithi, "Properties of eco-friendly pervious concrete containing polystyrene aggregates reinforced with waste PET fibers," Innovative Infrastructure Solutions, vol. 5, no. 3, Jul. 2020, Art. no. 77, https://doi.org/10.1007/s41062-020- 00323-w. [19] "Standard Test Method for Flexural Strength of Hydraulic-Cement Mortars," ASTM, West Conshohocken, PA, US, Standard C348-21, 2008. [20] A. Dixit, S. D. Pang, S.-H. Kang, and J. Moon, "Lightweight structural cement composites with expanded polystyrene (EPS) for enhanced thermal insulation," Cement and Concrete Composites, vol. 102, pp. 185–197, Sep. 2019, https://doi.org/10.1016/j.cemconcomp.2019.04. 023. [21] "Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus," ASTM, West Conshohocken, PA, US, Standard C177-19, 2019. [22] A. A. Sayadi, J. V. Tapia, T. R. Neitzert, and G. C. Clifton, "Effects of expanded polystyrene (EPS) particles on fire resistance, thermal conductivity and compressive strength of foamed concrete," Construction and Building Materials, vol. 112, pp. 716–724, Jun. 2016, https://doi.org/10.1016/j.conbuildmat.2016.02.218. [23] A. H. Medher, A. I. Al-Hadithi, and N. Hilal, "The Possibility of Producing Self-Compacting Lightweight Concrete by Using Expanded Polystyrene Beads as Coarse Aggregate," Arabian Journal for Science and Engineering, vol. 46, no. 5, pp. 4253–4270, May 2021, https://doi.org/10.1007/s13369-020-04886-9. [24] A. M. Neville and J. J. Brooks, Concrete Technology, 6th ed. UK: Longman Scientific and Technical, 1995.