 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 An Experimental Study of Plastic Waste as Fine Aggregate Substitute for Environmentally Friendly Concrete Anita Intan Nura Diana 1,* , Subaidillah Fansuri 1 , Akhmad Feri Fatoni 2 1 Department of Civil Engineering, Wiraraja University, Sumenep, Indonesia 2 Department of Nursing, Wiraraja University, Sumenep, Indonesia Received 29 December 2020; received in revised form 06 April 2021; accepted 07 April 2021 DOI: https://doi.org/10.46604/aiti.2021.6930 Abstract Decomposing plastics, including plastic bottles, is a very difficult process because it takes 50-100 years. Every year, the use of plastic bottles is increasing, but only few people are willing to treat plastic bottle waste. In this study, plastic bottle waste is used as a substitute of fine aggregate and shaped in such a way to have a sand-like gradation. The variations of graded plastic bottle waste are 0%, 5%, 10%, and 12%. The test objects for each variation consist of three specimens. Data are analyzed by using regression and classical assumption test with SPSS program. The results of the data analysis show that there is a simultaneous effect on the compressive strength with variations in plastic waste substitution. The compressive strength decreases with the increase in the percentage of plastic added. Maximum compressive strength is at the variations of 0% and 5% with19.192 MPa and 16.414 MPa, respectively. Keywords: environmentally friendly concrete, plastic waste, compressive strength 1. Introduction Plastic bottle waste is one of the most common environmental problems in this era. Plastic is a material that is difficult to decompose, taking up to 50-100 years. Every year, the amount of plastic bottle waste is increasing because people use plastic-based packaging almost every day. Nonetheless, people are less aware that behind the use of plastic materials, the recycling process of plastic bottle waste is not optimal. Some people recycle plastic bottle waste by converting them into vases, bags, and furniture so that it can be reused. However, the results of the survey conducted in Sumenep area regarding the recycling process of plastic bottle waste are still limited. In the field of structure and materials, there have been many studies using plastic bottle waste as a research subject. Using plastic bottle waste as construction materials can reduce environmental damages caused by plastic waste pollution. In this study, plastic bottle waste is used as a substitute of fine aggregate and shaped in such a way so that its gradation is similar to the common fine aggregate, i.e. the sand. Sand is the main ingredient for making concrete. The sand used in the concrete mixture is black sand, which is more suitable than other types of sand for building construction. The black sand content has a good binder with other concrete mixture materials. Behind the excellent use of black sand in building construction, a very serious problem arises. Land damage has often occurred due to uncontrolled mining of black sand (illegal mining) around the sand mining area. In the last few years, there have been conflicts that claimed the lives of environmentalists in the mining areas, including Lumajang area. Every day, black sand mining is carried out in the Lumajang area to meet consumer demand without any restrictions on black sand mining which will have a negative impact on the surrounding environment. * Corresponding author. E-mail address: anita@wiraraja.ac.id Tel.: +62-81332299841 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Sumenep does not have black sand materials for infrastructure purposes. The black sand in Sumenep Regency is imported from outside the city. Therefore, it is not surprising that the price of black sand in Sumenep Regency is quite high since the demand is high. As a result, people in Sumenep Regency have started many private companies and agencies that prioritize in building materials for fine aggregate using black sand. Various studies have been carried out on utilizing plastic waste as a substitute of fine aggregate [1-11]. Guendouz et al. [1] investigated the use of two types of plastic scrap with the PET and LDPE logos used for the manufacture of fine aggregate in the form of powder in concrete z. Diana and Depriyanto [2] examined the effect of adding plastic fibers to paving blocks on compressive strength, shock resistance, and water absorption. Karimah [3] studied the compressive strength of normal strength concrete by adding 15%, 30%, and 45% LDPE plastic waste. Alvine [4] investigated the compressive strength of concrete by adding 20%, 40%, and 60% ABS plastic waste. Previous research combined plastic waste with other materials as a substitute for concrete mixtures. Among these materials are electronic plastic waste and marble dust on hardened properties of high-strength concrete [9] and plastic/rubber waste as environmentally friendly aggregates for concrete mixtures [10]. Adela, Behanu, and Gobena [11] utilized plastic waste as an alternative material for coarse aggregates. Several studies have shown that adding a number of plastic waste to the concrete mixture can reduce the quality of the concrete production [9-11]. Based on the previous research, further research on the use of plastic waste for concrete mixture is needed. Research can be in the form of variations in processing plastic waste and the addition of additives. Table 1 Literature review Ref. Plastic type Shape Replacement level Aggregate replacement type Application [1] PET + LDPE Fibers and powder Powder: 10%, 20%, 30%, and 40% Fibers: 0.5%, 1%, 1.5%, and 2% Fine Concrete [2] PET Fibers 0%, 0.25%, 0.50%, 0.75%, and 1% Coarse Paving block [3] LDPE Flakes 15%, 30%, and 45% Coarse Concrete [4] ABS Flakes and powder 20%, 40%, and 60% Coarse and fine Concrete [5] E-plastic waste Flakes 0%, 5.5%, 11%, and 16.5% Coarse Concrete [6] LDPE Powder particles below 75 μm Fine - [7] LDPE Shredded 5%, 10%, 15%, 20%, and 25% Fine Concrete [8] LDPE Powder 15% and 30% Fine Concrete [9] E-plastic waste Irregular flakes 0%, 10%, 20%, 30%, and 40% Coarse and fine Concrete [11] Plastic bags and plastic bottles Irregular 0%, 25%, 35%, and 50% Coarse Concrete Table 1 shows several types and shape of plastic waste that have been used in previous studies. Based on the background discussion above, only few researchers in Sumenep district utilized plastic waste as substitute of fine aggregate in concrete mixture.This study focuses on the use of graded plastic bottle waste (the plastic type is PET) as a substitute of fine aggregate, and uses the local coarse aggregates originating from Duko Village, Rubaru District, and Sumenep Regency based on the results of research conducted by Fansuri et.al [12]. The use of local materials is intended as a form of sustainability of construction materials by local construction actors in Sumenep Regency. 2. Research Methodology 2.1. Flow chart of the study Fig. 1 shows the flow chart of the approach for this study. The process consists of five steps: problem statement, data collection, analysis data, result and discussion, and conclusions.The five steps are described as follows: 180 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Step 1: problem statement The most important background is the plastic bottle waste problem that we face in this era. Plastic is a material that is difficult to decompose, which takes 50-100 years to decompose. Every year the amount of plastic bottle waste is increasing because almost every day people use plastic-based packaging. It takes innovation to turn plastic waste into construction materials (see introductory section for detailed explanations). Step 2: data collection Data are divided into primary data and secondary data. Primary data are collected through experiments in the Civil Engineering Laboratory by testing the aggregate materials for their density, water content, and sieve analysis, by making fresh concrete started with the calculation of mix design, manufacture of test object, slump test, concrete molding, and concrete curing, and by testing the compressive strength of fresh concrete. Secondary data are obtained by reviewing similar previous research and by testing the standards used in the study. The standards include the specific gravity test, water absorption of fine and coarse aggregates, fine aggregate and coarse aggregate sieve analysis testing, concrete manufacturing procedures, and concrete compressive strength testing. Step 3: data analysis Primary data are especially analyzed by using classical assumption tests (linearity test, normality test, and heteroscedasticity test) and linier regression. All the analyses in the study are executed by using SPSS software. Step 4: result and discussion At this stage, all the experimental and analytical results will be displayed in the form of tables, figures, and detailed calculations. Then, the obtained experimental results and analysis are compared with the previous literature. Step 5: conclusion At this stage, conclusions and recommendations will be obtained from the results of the experiments and analyses that have been carried out. Fig. 1 Research methodology 2.2. Model The model used in this study is fresh concrete with a mixture of plastic bottle waste. Plastic bottles are cut into small pieces to resemble grading sand. Furthermore, the small pieces of plastic waste used as a substitute for sand for the concrete mixture are divided into several variations. There are three concrete specimens as samples for each variation. The concrete compressive strength test is carried out for 14 days. Table 2 presents the test objects for each substitute variation. Problem Statement Data Collection Primary Data Secondary Data Analysis Data Results and Discussion Conclusions 181 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Table 2 Plastic gradient variation for each specimen Plastic gradient variations Specimen for each variation 0% 3 5% 3 10% 3 12% 3 Total samples 12 2.3. Data analysis The data to be analyzed are obtained from the results of testing in the laboratory. Data from the laboratory are presented in tables and graphs. Data are analyzed using linear regression with classical assumption tests (linearity test, normality test, and heteroscedasticity test). All the analyses use SPSS program which are presented in the form of tables, pictures, and descriptions. 3. Results and Discussion The results of this study consist of several test results for concrete mixtures (fine and coarse aggregate). After concrete compressive strength tests are carried out at the Civil Engineering Laboratory, compressive strength test data are analyzed using SPSS software. The results of the study are described below. 3.1. Fine aggregate experiments There are several experiments carried out in the laboratory to determine the quality of fine aggregate, including water content experiment, specific gravity experiment [13], and sieve analysis experiment [14]. The following is the result of the water experiments in the laboratory. Table 3 Data testing and calculation of fine aggregate water content Experiment 1 2 3 Weight of original fine aggregate (W1) 500 gr 500 gr 500 gr Weight of oven-dry fine aggregate (W2) 485 gr 487 gr 486 gr Water content of fine aggregate (W1 − W2) / W2 × 100% 3.52% 2.67% 2.88% Average of water content 3.023% From the test shown in Table 3, it can be seen that the average value of fine aggregate water content is 3.023%. The greater the difference between the original weight of the fine aggregate and the weight of the fine aggregate after being heated, the more water the aggregate will contain. From the test shown in Table 4, it can be seen that dry specific gravity is 2.56, Saturated Surface Dry (SSD) is 2.62, apparent specific gravity is 2.71, and absorption is 2%. Detailed calculations can be seen in Table 4. Table 4 Data testing and calculation of fine aggregate density Experiment 1 2 3 Average Weight of pycno + SSD fine aggregate + water (W1) 1005 1019 1017 - Weight of SSD fine aggregate (500 gr) 500 500 500 - Weight of pycno + water (W2) 705 705 705 - Weight of oven-dry fine aggregate (W3) 490 490 490 - Dry specific gravity = W3 / (W2 + 500 − W1) 2.45 2.63 2.60 2.56 SSD specific gravity = 500 / (W2 + 500 − W1) 2.50 2.69 2.66 2.62 Apparent specific gravity = W3 / (W2 + W3 − W1) 2.58 2.78 2.75 2.71 Absorption = [(500 − W3) / 500] × 100% 2% 2% 2% 2% 182 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Figs. 2-5 illustrate the fine aggregate grading zone graphs. The value to illustrate the graph of the fine aggregate zone is obtained from Table 5. From the fine aggregate gradation graphs, it can be seen that the fine aggregate used is at the gradation limit no. 3. Furthermore, the amount of sand replaced by plastic bottle waste adjusts the selected gradation. It is done so that the plastic grading is similar to the sand grading used. The materials used in this study are shown in Fig. 6. Table 5 Data testing and calculation of fine aggregate sieve analysis Filter size Restrained weight (gr) Cumulative restrained weight (gr) Cumulative restrained (%) Cumulative passes (%) mm inch 4.8 3/8 30 30 3 96.95 2.36 8 46 76 7.72 92.28 1.70 12 60 136 13.81 86.19 1.18 16 73 209 21.22 78.78 0.60 30 210 419 42.54 57.46 0.425 40 160 579 58.78 41.22 0.30 50 42 621 63.05 36.95 0.15 100 301 922 93.60 6.40 0.075 200 48 970 98.48 1.52 Pan 15 985 100 0 Total 985 - 0 20 40 60 80 100 0.01 0.1 1 10 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 2 Fine aggregate gradation limit no. 1 0 20 40 60 80 100 0.01 0.1 1 10 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 3 Fine aggregate gradation limit no. 2 0 20 40 60 80 100 0.01 0.1 1 10 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 4 Fine aggregate gradation limit no. 3 183 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 0 20 40 60 80 100 0.01 0.1 1 10 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 5 Fine aggregate gradation limit no. 4 (a) Sand (b) Plastic bottle waste (c) Graded plastic Fig. 6 Materials used in this study 3.2. Coarse aggregate experiment There are several experiments conducted in the laboratory to determine the quality of the local coarse aggregate in Duko Village, Rubaru District [12]. The experiments include sieve analysis experiment [14] and water content experiment, specific gravity experiment [15]. The followings are the results of the experiments. Table 6 Data testing and calculation of coarse aggregate water content Experiment 1 2 3 Weight of original coarse aggregate (W1) 500 gr 500 gr 500 gr Weight of oven-dry coarse aggregate (W2) 401 gr 401 gr 401 gr Water content of coarse aggregate (W1 − W2) / W2 × 100% 24.7% 24.7% 24.7% Average of water content 24.7% From the test shown in Table 6, it can be seen that the average of coarse aggregate water content value is 24.7%. The greater the difference between the original weight of the fine aggregate and the weight of the fine aggregate after being heated, the more water the aggregate will contain. From the test shown in Table 7 below, it can be seen that the dry specific gravity is 2.02, SSD specific gravity is 2.52, apparent specific gravity is 4.03, and absorption is 24.69%. Table 7 Data testing and calculation of coarse aggregate density Experiment 1 2 3 Average Weight of the test specimen in saturated surface dry condition (W1) 500 500 500 - Bucket weight in water (W2) 631 631 631 - Bucket weight + specimen in water (W3) 930 935 932 - Weight of oven-dry coarse aggregate (W4) 401 401 401 - Dry specific gravity = W4 / (W2 + W1 − W3) 2.00 2.05 2.02 2.02 SSD specific gravity = W1 / (W2 + W1 − W3) 2.49 2.55 2.51 2.52 Apparent specific gravity= W4 / (W2 + W4 − W3) 3.93 4.13 4.01 4.03 Absorption = [(W1 − W4) / W4] × 100% 24.69% 24.69% 24.69% 24.69% 184 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Figs. 7-9 illustrate the coarse aggregate grading zone graphs. The value to illustrate the graph of the coarse aggregate zone is obtained from Table 8. Based on the experimental results and gradation limit of coarse aggregate sieve analysis, it is obtained that the coarse aggregate gradation is in the coarse aggregate gradation with a maximum size of 40 mm. Table 8 Data testing and calculation of coarse aggregate sieve analysis Filter size Restrained weight (gr) Cumulative restrained weight (gr) Cumulative restrained (%) Cumulative passes (%) mm inch 76.20 3 0 0 0 100 50.8 2 0 0 0 100 38.1 1.5 0 0 0 100 25.40 1 318 318 35.14 64.86 19 3/4 235 553 61.10 38.90 13.20 1/2 70 623 68.84 31.16 8.5 3/8 110 733 80.99 19.01 4.75 #4 160 893 98.67 1.33 2.36 #8 12 905 100 0 0.15 100 0 905 100 0 Pan 0 905 100 0 Total 1000 - 0 20 40 60 80 100 1 10 100 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 7 Coarse aggregate gradation limit (10 mm) 0 20 40 60 80 100 1 10 100 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 8 Coarse aggregate gradation limit (20 mm) 0 20 40 60 80 100 1 10 100 % C u m m u la ti v e Filter Size Lower Limit Upper Limit % Cummulative Passes Fig. 9 Coarse aggregate gradation limit (40 mm) 185 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 3.3. Concrete mix design planning Mix design planning is an important stage in concrete planning. Based on the mix design planning, the composition of coarse aggregate, fine aggregate, cement, and water can be obtained. In this study, mix design planning uses the Indonesian National Standard (SNI) 03-2834 [16]. Data of concrete mixture material are used to create three specimens for each variation, providing the required compressive strength in 23 Mpa equivalents to K270. Concrete mixture data for each variation is shown in Table 9. Table 9 Data of concrete mixture material Concrete mixture material Variation 0% (kg) Variation 5% (kg) Variation 10% (kg) Variation 12% (kg) Total (kg) Cement 3.43 3.43 3.43 3.43 13.72 Water 2.035 2.035 2.035 2.035 8.14 Coarse aggregate 12.571 12.571 12.571 12.571 50.284 Fine aggregate 8.109 7.704 7.298 7.136 30.247 Plastic bottle waste - 0.405 0.811 0.973 2.189 3.4. Concrete slump testing In this study, the stages and calculations of concrete slump testing use the procedure listed in the Indonesian National Standard (SNI) 1972 [17]. Fig. 10 shows the tool used in the slum test, namely the abram cone. The test tool must be a mold made of a metal material that is not sticky and does not react with cement paste. The thickness of the metal shall not be less than 1.5 mm, and when it is formed by a spinning process, there shall be no dots in the mold and its thickness is smaller than 1.15 mm. The mold must be cone-shaped with a base diameter of 203 mm, top diameter of 102 mm, and height of 305 mm. The base and top faces of the cone must be open and parallel to each other and perpendicular to the axis of the cone. The mold must be equipped with a treadle section and a handle as shown in Fig. 10. Fig. 10 Mold for slump test (abram cone) Table 10 Data testing and calculation of slump value Plastic waste variation Mold of slump test height (cm) Height of each specimen (cm) Slump value for each specimen (cm) Average (cm) 1 2 1 2 0% 30 19 21 11 9 10 5% 30 21 21 9 9 9 10% 30 20 22 10 8 9 12% 30 22 21 8 9 8.5 Based on Table 10, which shows the slump plan set in 60-180 mm, the results of the laboratory experiments meet the requirements. The lowest average value of the slump test is 85 mm and the highest value is 100 mm. This value is within the planned slump value. 186 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 3.5. Concrete compressive strength This concrete compressive strength test is carried out according to the procedure in the Indonesian National Standard (SNI) 1974 [18]. The detailed results of the concrete compressive strength test can be seen in Tables 11-14. Table 11 Data testing and calculation of concrete compressive strength value in 0% variation Sample Date Weight (kg) P (N) A (mm 2 ) Age conversion (14 days) Compressive strength (f’c) MPa Characteristic concrete (K) kg/cm 2 Create Test 1 06/05/2020 20/05/2020 8.143 340000 22500 0.88 17.172 206.888 2 06/05/2020 20/05/2020 8.064 395000 22500 0.88 19.949 240.355 3 06/05/2020 20/05/2020 8.083 405000 22500 0.88 20.455 246.440 Average of variation: 0% 19.192 231.228 Table 12 Data testing and calculation of concrete compressive strength value in 5% variation Sample Date Weight (kg) P (N) A (mm 2 ) Age conversion (14 days) Compressive strength (f’c) MPa Characteristic concrete (K) kg/cm 2 Create Test 1 12/05/2020 26/05/2020 7.926 410000 22500 0.88 20.707 249.483 2 12/05/2020 26/05/2020 7.615 360000 22500 0.88 18.182 219.058 3 12/05/2020 26/05/2020 8.058 205000 22500 0.88 10.354 124.741 Average of variation: 5% 16.414 197.761 Table 13 Data testing and calculation of concrete compressive strength value in 10% variation Sample Date Weight (kg) P (N) A (mm 2 ) Age conversion (14 days) Compressive strength (f’c) MPa Characteristic concrete (K) kg/cm 2 Create Test 1 18/05/2020 01/06/2020 7.240 240000 22500 0.88 12.121 146.039 2 18/05/2020 01/06/2020 7.200 185000 22500 0.88 9.343 112.571 3 18/05/2020 01/06/2020 7.160 200000 22500 0.88 10.101 121.699 Average of variation: 10% 10.522 126.770 Table 14 Data testing and calculation of concrete compressive strength value in 12% variation Sample Date Weight (kg) P (N) A (mm 2 ) Age conversion (14 days) Compressive strength (f’c) MPa Characteristic concrete (K) kg/cm 2 Create Test 1 18/05/2020 01/06/2020 7.284 215000 22500 0.88 10.859 130.826 2 18/05/2020 01/06/2020 7.140 210000 22500 0.88 10.606 127.784 3 18/05/2020 01/06/2020 7.247 200000 22500 0.88 10.101 121.699 Average of variation: 12% 10.522 126.770 Fig. 11 shows the relationship between the variations of plastic waste substitution in the fine aggregate of concrete mixture and the result of compressive strength value. The highest compressive strength is shown by concrete without plastic waste substitution in the concrete mixture (19.19 MPa in 0% variation). There is a decrease in compressive strength that is in line with the increase in the amount of plastic waste added to the concrete mixture. All the results of the compressive strength of the concrete, none of them meets the compressive strength requirements in 23 MPa. There are several factors that cause failure to pass in this experiment. First, the coarse aggregate material used do not meet the overall SNI requirements. The aggregate material in this study uses the local aggregate in Sumenep area. In a study conducted by Fansuri et al. [12] in five local coarse aggregate mining locations, namely Batuan village, Batu Putih village, Dasuk village, Duko village, and Ellak Daya village, it can be seen that the aggregate in Duko village met the parameters of coarse aggregate as a concrete material, where the water absorption was 1.83% (maximum value is 3%), specific gravity was 187 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 2.57 (minimum value is 1.8), test value wear and tear using Los Angeles was 24.8% (maximum value is 40%), and volume weight was 2075.5 kg/m 3 (minimum value is 2200 kg/m 3 ). Second, several studies that have been done previously explained that the use of additives in the form of additives (chemical compounds) is needed as the liquid can add strength to concrete with variations of plastic waste. Meanwhile, the experiments conducted in this study do not use added materials in the form of additives (chemical compounds). 0 5 10 15 20 25 0% 5% 10% 15% C o m p re s s iv e s tr e n g th v a lu e ( M p a ) Variation of plastic waste Fig. 11 Compressive strength relationship and plastic waste variations 3.6. Normality test of concrete Normality test in this study uses the SPSS for windows program. The normality test is used to determine whether the obtained research data has a normal distribution or not. From Table 15, it can be seen that the spread of unstandardized residual value is normal because the significant value is 0.200 > 0.05 (normally distributed). Therefore, this analysis can be processed to regression analysis because the conditions in the classical assumption test, in this case the residual value, have been stated as normally distributed. Table 15 Normality test result of unstandardized residual using one-sample Kolmogorov-Smirnov test N 12 Normal parameters a,b Mean 0.0000000 Std. deviation 31.61054075 Most extreme differences Absolute 0.194 Positive 0.194 Negative -0.183 Test statistic 0.194 Asymp. sig. (2-tailed) 0.200 c,d a. Normal test distribution b. Calculated from data c. Lilliefors significance correction d. Lower bound of the true significance 3.7. Heteroscedasticity test of concrete This test is used to determine deviation of the classic assumptions of heteroscedasticity because there is an inequality of variance from one residual observation to another, while in the regression model, it is actually expected to be constant. In this test, the researchers use the SPSS 25 for windows program and the Glejtser method. The symptom of heteroscedasticity is shown by the regression coefficient of the independent variable on the absolute value of the residual. In decision making, there is no symptom of heteroscedasticity if the probability value is greater than the alpha value (0.05). From Table 16, it can be concluded that heteroscedasticity do not occur in the regression model because the sig. variation of plastic waste to the absolute residual is 0.386 > 0.05. 0% 5% 10% 15% Variation of plastic waste 188 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 Table 16 Result of heteroscedasticity test of concrete Model Unstandardized coefficient Standardized coefficient T Sig. B Std. error Beta 1 Constant 30.647 10.761 - 2.848 0.017 Plastic waste variation -1.189 1.312 -0.275 -0.906 0.386 a. Dependent variable: RE3 3.8. Hypotheses test and regression equations There are two variables in this study, namely independent variable (X) and dependent variable (Y). Variable X is variation of plastic waste, and variable Y is concrete compressive strength. The hypotheses in this study are as follows. (1) Ho: There is no simultaneous effect between variable X on variable Y. (2) Ha: There is a simultaneous effect between variable X on variable Y. Table 17 ANOVA test result ANOVA a Model Sum of squares Df Mean square F Sig. 1 Regression 23784.941 1 23784.941 21.639 0.001 b Residual 10991.489 10 1099.149 - - Total 34776.430 11 - - - a. Dependent variable: Compressive strength b. Predictors: Constant, Plastic waste variation Hypotheses test can be done using the F test and significance test (probability). The test rule is to use the F test under several conditions: if F value ≤ F table, Ho is accepted; if F value > F table, Ho is rejected. Based on the calculation, the F value of the ANOVA table is 21.639 and the F table value is 4.96. Thus, it can be concluded that F value > F table. It means Ho is rejected, or in other words, Ha is accepted (there is simultaneous effect between variable X on variable Y). The significance test (probability) is conducted under several conditions: if probability (sig.) > α, Ho is accepted; if probability (sig.) < α, Ho is rejected. Based on Table 17, the probability value (sig.) = 0.001 and the significant level value α = 0.05. Therefore, it can be concluded that the probability value (sig.) < α. It means Ho is rejected, or in other words, Ha is accepted (there is a simultaneous effect between variable X on variable Y). Table 18 Coefficient results of compressive strength regression analysis Coefficient a Model Unstandardized coefficients Standardized coefficients T Sig. 95% Confidence interval for B B Std. error Beta Lower bound Upper bound 1 Constant 235.162 16.853 - 13.954 0.000 197.611 272.713 Plastic waste variation -9.560 2.055 -0.827 -4.652 0.001 -14.139 -4.981 a. Dependent variable: Compressive strength Based on Table 18, it can be analyzed that the regression equation model for the simultaneous effect on compressive strength with plastic waste variation is Y = 235.162 – 9.560 X, compressive strength without the addition of variation of plastic bottle waste is X = 0, and the value of compressive strength is (Y) = 235.162 kg/cm 2 (19.518 MPa). If the addition of variation of plastic bottle waste is X = 1%, it is estimated that the value of compressive strength (Y) = 235.162 – 9.560 (1) = 225.602 kg/cm 2 (18.725MPa) is added. Every 1% addition of plastic bottle waste will decrease the compressive strength of the concrete by 9.560 kg/cm 2 (0.793 MPa). 189 Advancesin Technology Innovation, vol. 6, no. 3, 2021, pp. 179-190 4. Conclusions Based on the results of the analysis and discussion in the previous section, the following conclusions are obtained. (1) The linear regression equation for the variation of plastic waste on the compressive strength of concrete is Y=235.162– 9.560X, meaning that there is a significant influence between the variation of plastic waste on the compressive strength of concrete. (2) The more plastic waste added into the variation, the lower the concrete compressive strength, where the maximum compressive strength is at the variations of 0% and 5%, namely 19.192 MPa for the variation of 0% and 16.414MPa for the variation of 5%. In general, the concrete which contains more plastic has poorer durability performance. Conflicts of Interest The authors declare no conflict of interest. References [1] M. Guendouz, F. Debieb, O. Boukendakdji, E. H. Kadri, M. Bentchikou, and H. Soualhi, “Use of Plastic Waste in Sand Concrete,” Journal of Materials and Environmental Science, vol. 7, no. 2, pp. 382-389, October 2016. [2] A. I. N. Diana and H. 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