The results of compressive strength for concrete reinforced by adding 2.5 of wastes cigarette butts (W.C.B) by volume are present in this chapter. In this study, three type of mixing concrete mixes will be designed for constant grade 30 but using different percentage of water to cement ratio (w/c). The w/c is 0.55, 0.60 and 0.65 were conducted. In this present study, there are attempt in utilize of cigarette butts in fired clay bricks conducted by Aeslina et al., 2010. Four variables of mixing are using different percentages of cigarette butts which are 0%, 2.5%, 5.0% and 10.0% by weight. The compressive strength test shows that the strength decreases with the increasing proportion of cigarette butts. The compressive strength test determines the maximum load that the specimen could sustained over cross sectional area at ages 134 days.

Workability for Concrete Specimens

Workability test include slump test, vebe test and compacting factor test. In this study, each of the tests was conducted to test three types of mix which have w/c 0.55, w/c 0.60 and w/c 0.65 and a control mix of w/c 0.55. The results of all the tests were tabulated in Table 4.1, Table 4.2 and Table 4.3 respectively.

Slump Test for Concrete Specimens

Table 4.1 shows the result of slump test for three types of different w/c specimens with constant amount of W.C.B and a control mix specimen that without the W.C.B contents. Control mix specimen gave a 70mm of slump which is the lowest slump value compare to the other specimens that mixed with W.C.B. For specimens with w/c 0.55, w/c 0.60 and w/c 0.65, their slump values were 85mm, 120mm and 150mm respectively. It was shown that the w/c of 0.65 has the highest slump and highest workability in this study. Figure 4.1 illustrated the result of slump test for different mix specimens. Table 4.1: Results of Slump Test for Different Mix Specimens Water to Cement Ratio (w/c) Slump (mm) Control Mix 70 0.55 85 0.60 120 0.65 150 Figure 4.1: Results of Slump Test for Different Mix Specimens

Vebe Test for Concrete Specimens

Table 4.2 shows the results of Vebe test for three types of different w/c specimens with constant amount of W.C.B and a control mix specimen without the W.C.B content. There was 3.20seconds of Vebe obtained for the control mix specimen, which is the highest among other specimens. For w/c 0.55, there is 3.05s while for w/c 0.60, 2.70s was obtained. Specimen with w/c of 0.65 has the lowest Vebe which has only 2.25s which has the highest workability. Figure 4.2 illustrated the result of Vebe test for different mix specimens. Table 4.2: Results of Vebe Test for Different Mix Specimens Water to Cement Ratio (w/c) Vebe (s) Control Mix 3.20 0.55 3.05 0.60 2.70 0.65 2.25 Figure 4.2: Results of Vebe Test for Different Mix Specimens

Compacting Factor Test for Concrete Specimens

Table 4.3 shows the results of compacting factor for three types of different w/c specimens with constant amount of W.C.B and a control mix specimen without the W.C.B content. It was clearly shown that control mix has low compacting factor due to the large percentage of deviation 0.957% that is from 16.3kg to 15.6kg. Specimen with w/c 0.65 gave the lowest deviation 0.994% which is from 16.3kg to 16.2kg, hence it has highest compacting factor. For specimens of w/c 0.55 and w/c 0.60, their deviations were 0.982% and 0.988% respectively. Figure 4.3 illustrated the result of compacting factor test for different mix specimens. Table 4.3: Results of Compacting Factor for Different Mix Specimens Water to Cement Ratio (w/c) Weight (kg) Percent of Compacting% Before After Control Mix 16.3 15.6 0.957 0.55 16.7 16.4 0.982 0.60 16.6 16.4 0.988 0.65 16.3 16.2 0.994 Figure 4.3: Results of Compacting Factor for Different Mix Specimens

Compressive Strength for Concrete Specimens

The compressive strength test is carried out to determine the strength of the concrete cube with additional of waste cigarette butts (W.C.B) at ages 7, 14 and 28 days. The compressive strength was calculated using Equation 3.2 as mentioned in chapter 3. Three different mix of water cement ratio (w/c) were considered namely as Mix A (w/c 0.55), Mix B (w/c 0.60) and Mix C (w/c 0.65). A control mix with w/c 0.55 and no cigarette butt content was tested in order to compare the results from the specimens with Mix (A, B and C).

Effect of Water to Cement Ratio on Compressive Strength for Concrete Due to Different Mix at Ages 7 days

Table 4.4 shows the result of compressive strength for different w/c mix with addition of 2.5% of waste cigarette butts (W.C.B) by volume at ages of 7 days. Figure 4.4 illustrated that the compressive strength of concrete due to different mix at age 7 days. The results show that the compressive strength was decreasing with the increasing of water cement ratio (w/c). Compressive strength of 14.53MPa was obtained for w/c 0.55, 14.51MPa for w/c 0.60 and 10.91MPa for w/c 0.65 while the control mix achieved 19.00MPa. It is noticed that the compressive strength for w/c 0.55 is 14.53MPa which is decreases by 23.5% compared to the compressive strength of control mix. For w/c 0.60, it decreases by 23.6% while for w/c 0.65, it decreases by 42.6%. Table 4.4: Compressive Strength for Concrete Due to Different Mix at Ages 7 days Water to Cement Ratio (w/c) Compressive Strength (MPa) 1 2 3 Average Control Mix 17.99 19.49 19.52 19.00 0.55 14.31 15.01 14.17 14.53 0.60 14.38 14.65 14.51 14.51 0.65 10.08 11.32 11.34 10.91 Figure 4.4: Compressive Strength for Concrete Due to Different Mix at Ages 7 days

Effect of Water to Cement Ratio on Compressive Strength for Concrete Due to Different Mix at Ages 14 days

Table 4.5 shows the result of compressive strength for different w/c mix with addition of 2.5% of waste cigarette butts (W.C.B) by volume at ages of 14 days. Figure 4.5 illustrated that the compressive strength of concrete due to different mix at age 14 days. The results show that the compressive strength was decreasing with the increasing of water cement ratio (w/c). Compressive strength of 17.55MPa was obtained for w/c 0.55, 17.16MPa for w/c 0.60 and 11.81MPa for w/c 0.65 while the control mix achieved 20.37MPa. It is noticed that the compressive strength for w/c 0.55 is 17.55MPa which is decreases by 13.8% compared to the compressive strength of control mix. For w/c 0.60, it decreases by 15.8% while for w/c 0.65, it decreases by 42.0%. Table 4.5: Compressive Strength for Concrete Due to Different Mix at Ages 14 days Water to Cement Ratio (w/c) Compressive Strength (MPa) 1 2 3 Average Control Mix 21.22 20.38 19.52 20.37 0.55 19.61 16.55 16.50 17.55 0.60 19.76 15.82 15.89 17.16 0.65 11.26 12.35 11.82 11.81 Figure 4.5: Compressive Strength for Concrete Due to Different Mix at Ages 14 days

Effect of Water to Cement Ratio on Compressive Strength for Concrete Due to Different Mix at Ages 28 days

Table 4.6 shows the result of compressive strength for different w/c mix with addition of 2.5% of waste cigarette butts (W.C.B) by volume at ages of 28 days. Figure 4.6 illustrated that the compressive strength of concrete due to different mix at age 28 days. The results show that the compressive strength was decreasing with the increasing of water cement ratio (w/c). Compressive strength of 19.11MPa was obtained for w/c 0.55, 18.07MPa for w/c 0.60 and 15.47MPa for w/c 0.65 while the control mix achieved 22.42MPa. It is noticed that the compressive strength for w/c 0.55 is 17.55MPa which is decreases by 14.7% compared to the compressive strength of control mix. For w/c 0.60, it decreases by 19.4% while for w/c 0.65, it decreases by 31.0%. Table 4.6: Compressive Strength for Concrete Due to Different Mix at Ages 28 days Water to Cement Ratio (w/c) Compressive Strength (MPa) 1 2 3 Average Control Mix 23.00 23.60 20.67 22.42 0.55 19.19 19.17 18.98 19.11 0.60 17.49 17.52 19.19 18.07 0.65 15.42 15.47 15.51 15.47 Figure 4.6: Compressive Strength for Concrete Due to Different Mix at Ages 28 days

t-Test Analysis for Compressive Strength at Ages 28 days

The summary of t-test analysis for control mix is presented in Table 4.7. Since the null hypothesis stated that there was no statistically significant different between control mix and w/c 0.55, the analysis result failed to reject the null hypothesis as indicated by: tstat < tcrit (3.69<4.30) and P > Î± (0.07>0.05). Therefore it can be concluded, at 95% confidence level, there was no significant difference between control mix and the specimen which w/c is 0.55 as the alternative source material. Table 4.7: t-Test: Two-Sample Assuming Unequal Variances W/C

C/M

0.55

Mean 22.42333 19.11333 Variance 2.395633 0.013433 Observations 3 3 Hypothesized Mean Difference 0 df 2 t Stat 3.693722 P(T<=t) one-tail 0.033055 t Critical one-tail 2.919986 P(T<=t) two-tail 0.066109 t Critical two-tail 4.302653

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