3. Experimental studies and discussion

#### 3.1. Workability

Figure 2. Particle size distributions of fine aggregates.

136 Sustainable Buildings - Interaction Between a Holistic Conceptual Act and Materials Properties

Components CRTS content (%)

Cement (kg/m<sup>3</sup>

Fly Ash (kg/m<sup>3</sup>

Water (kg/m3

CRTS (kg/m3

Natural sand (kg/m3

Crushed sand (kg/m3

Coarse aggregate 1 (kg/m<sup>3</sup>

Coarse aggregate 2 (kg/m<sup>3</sup>

Unit weight (kg/m<sup>3</sup>

Table 2. Concrete mix designs.

0 5 10 15 20

) 300 300 300 300 300

) 60 60 60 60 60

) 155 155 155 155 155

) 0 94 188 282 376

Admixture (%) 1.30 1.30 1.30 1.30 1.30 Water/(FA + C) 0.43 0.43 0.43 0.43 0.43 Slump (mm) 170 160 158 150 143

) 517 517 517 517 517

) 360 270 180 90 0

) 470 470 470 470 470

) 512 512 512 512 512

) 2379 2383 2387 2391 2395

The workability was negatively affected with increasing CRTS content, as shown in Table 2. The slump value slightly decreased when the CRTS content increased by 5%. However, the slump decreased by only 2.75 cm when the CRTS content increased to 20%. According to Ling and Poon, fine particle size glass increases water absorption [38]. Similar to these results, Topcu and Canbaz reported that increasing glass content reduced the workability but the reduction was insignificant [15]. Concrete with glass requires more water to achieve the same workability [5, 21]. Ismail and Al-Hashmi, Kou and Xing, and Shayan and Xu, also reported that glass added to concrete decreases the workability [2, 15, 16].

#### 3.2. Unit weight and water absorption

Table 3 indicates that up to 15% CRTS content in concrete increases the density of hardened concrete in comparison to plain concrete. However, glass content above 15% decreases the density [23]. Changing the glass content from 15 to 20% produces the largest increase in water absorption, which suggests that glass content above 15% leads to higher porosity than specimens without CRTS. The study by Shayan and Xu also indicates that the density decreases


Table 3. Effect of CRTS content on the workability.


Table 4. Densities and water absorption of the specimens.

with glass addition above 15% as aggregate or glass powder [2]. The dry and saturated density of the concrete exhibits identical trends. Table 4 shows that the water absorption decreases from 6.46 to 6.05 when the CRTS composition reaches 10%. Water absorption increased when CRTS content is higher than 10% in the concrete. This increase is remarkable when the fraction is 20%.

#### 3.3. Compressive strength

The use of 15 and 20% CRTS decreased the compressive strength in concrete over the first 28 days in Figure 3. The study by Maschio et al. (2013) presents a similar relationship [39]. After 28 days, the rate of increase of strength was faster than that of P and specimens with 5 and 10% glass aggregate and approached these values for 15 and 20% CRTS in concrete [8]. This result demonstrates that the glass contents of 15 and 20% have a pozzolanic effect that becomes more obvious after 28 days [15]. The glass replacements of 5 and 10% do not significantly change either the early or the end strength values in comparison with P [6]. The specimen with 5% CRTS exhibited a notably constant value throughout the period of 90 days, which approached approximately 40 MPa after 90 days. An increase of compressive strength was observed for 10, 15, and 20% CRTS from 28 to 90 days, which can be attributed to the pozzolanic effect of CRTS [40]. Intervals of minimum and maximum compressive strengths for all specimens were 13–24, 22–30, 32–39, and 37–41 MPa for 3, 7, 28, and 90 days, respectively. After 90 days, the difference between the minimum and maximum values of the specimens was relatively small [8]. It is remarkable that the interval decreased from 9 to 4 in 90 days. However, the increase in glass content generally decreases the compressive strength [2]. Ling and Poon explained that the compressive strength might be negatively affected by the bonding between the glass particles and the cement paste [11].

and cracks originating from loading can spread faster [11, 41]. Therefore, the strength of the

Figure 4. SEM micrographs showing the bond between CRTS and cement paste in concrete after compression loading.

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The flexural strength-time graph is shown in Figure 5. The specimen with 5% CRTS replacement is notably similar to the P sample throughout 90 days in terms of the compressive strength. The flexural strengths for the 5% CRTS and P samples on the 28th and 90th days

concrete with glass aggregate decreases [2, 5, 14, 17, 41].

Figure 3. Improvement in compressive strength of the specimens over 90 days.

3.4. Flexural strength

SEM micrograph in Figure 4 displays the interface between concrete and CRTS exposed to compression. This micrograph was obtained by enlarging the field under SEM 500 times. This SEM micrograph was similar to those reported by Ling and Poon: a smooth surface of CRTS can lead to a weaker interface that results in loss of bonding between CRTS and cement paste, Research on Strength, Alkali-Silica Reaction and Abrasion Resistance of Concrete with Cathode Ray Tube Glass… http://dx.doi.org/10.5772/intechopen.73873 139

Figure 3. Improvement in compressive strength of the specimens over 90 days.

Figure 4. SEM micrographs showing the bond between CRTS and cement paste in concrete after compression loading.

and cracks originating from loading can spread faster [11, 41]. Therefore, the strength of the concrete with glass aggregate decreases [2, 5, 14, 17, 41].

#### 3.4. Flexural strength

with glass addition above 15% as aggregate or glass powder [2]. The dry and saturated density of the concrete exhibits identical trends. Table 4 shows that the water absorption decreases from 6.46 to 6.05 when the CRTS composition reaches 10%. Water absorption increased when CRTS content is higher than 10% in the concrete. This increase is remarkable when the fraction

CRTS content (%) 0 5 10 15 20 Slump (cm) 17 16 15.75 15 14.25

 2213 2354 6.46 2219 2363 6.26 2289 2427 6.05 2274 2413 6.09 2198 2354 6.97

138 Sustainable Buildings - Interaction Between a Holistic Conceptual Act and Materials Properties

) Saturated density (kg/m3

) Water absorption (%)

The use of 15 and 20% CRTS decreased the compressive strength in concrete over the first 28 days in Figure 3. The study by Maschio et al. (2013) presents a similar relationship [39]. After 28 days, the rate of increase of strength was faster than that of P and specimens with 5 and 10% glass aggregate and approached these values for 15 and 20% CRTS in concrete [8]. This result demonstrates that the glass contents of 15 and 20% have a pozzolanic effect that becomes more obvious after 28 days [15]. The glass replacements of 5 and 10% do not significantly change either the early or the end strength values in comparison with P [6]. The specimen with 5% CRTS exhibited a notably constant value throughout the period of 90 days, which approached approximately 40 MPa after 90 days. An increase of compressive strength was observed for 10, 15, and 20% CRTS from 28 to 90 days, which can be attributed to the pozzolanic effect of CRTS [40]. Intervals of minimum and maximum compressive strengths for all specimens were 13–24, 22–30, 32–39, and 37–41 MPa for 3, 7, 28, and 90 days, respectively. After 90 days, the difference between the minimum and maximum values of the specimens was relatively small [8]. It is remarkable that the interval decreased from 9 to 4 in 90 days. However, the increase in glass content generally decreases the compressive strength [2]. Ling and Poon explained that the compressive strength might be negatively affected by the bonding

SEM micrograph in Figure 4 displays the interface between concrete and CRTS exposed to compression. This micrograph was obtained by enlarging the field under SEM 500 times. This SEM micrograph was similar to those reported by Ling and Poon: a smooth surface of CRTS can lead to a weaker interface that results in loss of bonding between CRTS and cement paste,

is 20%.

3.3. Compressive strength

Table 3. Effect of CRTS content on the workability.

CRTS content (%) Dry density (kg/m<sup>3</sup>

Table 4. Densities and water absorption of the specimens.

between the glass particles and the cement paste [11].

The flexural strength-time graph is shown in Figure 5. The specimen with 5% CRTS replacement is notably similar to the P sample throughout 90 days in terms of the compressive strength. The flexural strengths for the 5% CRTS and P samples on the 28th and 90th days

Figure 5. Improvement in flexural strength of the specimens over 90 days.

were almost the same. The specimens with 10, 15, and 20% CRTS have similar trends each other. The maximum difference in values of flexural strength on 90th day decreases to 0.7 MPa, whereas it is 1 MPa after 28 days. The flexural strengths of P and 5% CRTS concrete are approximately 5 MPa at 90 day, whereas the others approach approximately 4.5 MPa. The increase in glass content in the mix generally decreases the flexural strength [2, 8, 14].

Figure 6. Improvement in ultrasonic pulse velocity of the specimens over 90 days.

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Figure 7. Static and dynamic elasticity moduli of the specimens at 28 days.

#### 3.5. Ultrasonic pulse velocity

The pulse velocity graph in Figure 6 reveals that the specimen with 20% CRTS replacement exhibits relatively low values for the first 28 days in comparison with the others. The specimens with 5 and 10% CRTS replacement exhibit a relatively higher pulse velocity than P for the first 28 days. Their values are almost identical to that of P at the end of 90 days. All specimens have notably similar pulse velocity values at the end of 90 days, and there are also differences between 28 and 90 days, as shown in the graphs of compressive and flexural strengths in Figures 3 and 5. The ultrasound pulse velocity is approximately proportional to the compressive and flexural strengths [2].

#### 3.6. Static and dynamic elasticity moduli

Static and dynamic elasticity modulus values are very similar in Figure 7. The dynamic elasticity modulus found using the ultrasonic pulse velocity is generally larger than the static Research on Strength, Alkali-Silica Reaction and Abrasion Resistance of Concrete with Cathode Ray Tube Glass… http://dx.doi.org/10.5772/intechopen.73873 141

Figure 6. Improvement in ultrasonic pulse velocity of the specimens over 90 days.

were almost the same. The specimens with 10, 15, and 20% CRTS have similar trends each other. The maximum difference in values of flexural strength on 90th day decreases to 0.7 MPa, whereas it is 1 MPa after 28 days. The flexural strengths of P and 5% CRTS concrete are approximately 5 MPa at 90 day, whereas the others approach approximately 4.5 MPa. The

The pulse velocity graph in Figure 6 reveals that the specimen with 20% CRTS replacement exhibits relatively low values for the first 28 days in comparison with the others. The specimens with 5 and 10% CRTS replacement exhibit a relatively higher pulse velocity than P for the first 28 days. Their values are almost identical to that of P at the end of 90 days. All specimens have notably similar pulse velocity values at the end of 90 days, and there are also differences between 28 and 90 days, as shown in the graphs of compressive and flexural strengths in Figures 3 and 5. The ultrasound pulse velocity is approximately proportional to

Static and dynamic elasticity modulus values are very similar in Figure 7. The dynamic elasticity modulus found using the ultrasonic pulse velocity is generally larger than the static

increase in glass content in the mix generally decreases the flexural strength [2, 8, 14].

Figure 5. Improvement in flexural strength of the specimens over 90 days.

140 Sustainable Buildings - Interaction Between a Holistic Conceptual Act and Materials Properties

3.5. Ultrasonic pulse velocity

the compressive and flexural strengths [2].

3.6. Static and dynamic elasticity moduli

Figure 7. Static and dynamic elasticity moduli of the specimens at 28 days.

elasticity modulus. The specimen with 5% CRTS replacement in concrete has the highest value, and that with 10% glass replacement has a better value than the specimen without CRTS. The specimens with 15 and 20% replacement have notably similar values, which are slightly lower than that of the specimen without CRTS [2, 23]. The elasticity moduli of all specimens are related to the compressive strength, flexural strength, and ultrasonic pulse velocity at 28 days [42].

#### 3.7. Alkali-silica reaction

The 21-day expansion of the mortar bars is shown in Figures 8 and 9. In Figures 8 and 9, the expansion can be observed to increase with increasing CRTS content and time. The bars with fly ash in Figure 8 expand slightly less than the bars without fly ash (CRTS-F) in Figure 9 because of the pozzolanic effect of fly ash [43]. After 21 days, all specimens with CRTS have similar values except for the specimens without CRTS. The highest expansion for the specimens with 20% CRTS is less than 0.03% in Figures 8 and 9, which is below the upper limit of 0.1% according to ASTM C1260. The study of Zhao et al. (2013b) also showed the expansion value of FA series mortar samples with glass sand are found to be below 0.1% [44]. The importance of using fine glass was reported by Ismail and Al-Hashmi, who used aggregate with a fineness modulus of 2.36, which decreased the ASR. In this study, the fineness modulus of the CRTS is 2.95, which indicates that the aggregate is sufficiently fine for ASR resistance.

Figure 9. Improvement in ASR of the specimens without fly ash over 21 days.

by Turgut and Yahlizade.

Figure 10. Change in abrasion loss (%) of the specimens after 28 days as a function of CRT comparing with the research

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Figure 8. Improvement in ASR of the specimens over 21 days.

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Figure 9. Improvement in ASR of the specimens without fly ash over 21 days.

elasticity modulus. The specimen with 5% CRTS replacement in concrete has the highest value, and that with 10% glass replacement has a better value than the specimen without CRTS. The specimens with 15 and 20% replacement have notably similar values, which are slightly lower than that of the specimen without CRTS [2, 23]. The elasticity moduli of all specimens are related to the compressive strength, flexural strength, and ultrasonic pulse velocity at

142 Sustainable Buildings - Interaction Between a Holistic Conceptual Act and Materials Properties

The 21-day expansion of the mortar bars is shown in Figures 8 and 9. In Figures 8 and 9, the expansion can be observed to increase with increasing CRTS content and time. The bars with fly ash in Figure 8 expand slightly less than the bars without fly ash (CRTS-F) in Figure 9 because of the pozzolanic effect of fly ash [43]. After 21 days, all specimens with CRTS have similar values except for the specimens without CRTS. The highest expansion for the specimens with 20% CRTS is less than 0.03% in Figures 8 and 9, which is below the upper limit of 0.1% according to ASTM C1260. The study of Zhao et al. (2013b) also showed the expansion value of FA series mortar samples with glass sand are found to be below 0.1% [44]. The importance of using fine glass was reported by Ismail and Al-Hashmi, who used aggregate with a fineness modulus of 2.36, which decreased the ASR. In this study, the fineness modulus of the CRTS is 2.95, which indicates that the aggregate is sufficiently fine for ASR

28 days [42].

resistance.

Figure 8. Improvement in ASR of the specimens over 21 days.

3.7. Alkali-silica reaction

Figure 10. Change in abrasion loss (%) of the specimens after 28 days as a function of CRT comparing with the research by Turgut and Yahlizade.

#### 3.8. Abrasion resistance

Figure 10 shows the results of abrasion volume loss (%) found using the Bohme abrasion test machine. It clearly appears that the abrasion volume loss (%) decreases with increasing [18–20, 45]. The research by Turgut and Yahlizade supports these results. They found that the use of glass replacement with fine aggregate up to 20% by weight decreased the abrasion volume loss (%). In this research, the decrease slows down between 5 and 15%; however, Turgut and Yahlizade did not investigate these proportions. The difference of abrasion volume loss of specimen with glass content of 20% compared to the specimen without CRTS is approximately 2.5% in this research; whereas it was 2% in the research by Turgut and Yahlizade. Their study was based on concrete paving blocks and window glass.

7. The abrasion volume loss (%) decreases with increasing CRTS content up to 20%. The

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In conclusion, the concrete with CRTS aggregate exhibits a performance similar to that of the concrete without CRTS. This result shows that the use of CRTS can contribute to the properties of concrete. The mixture of CRTS in concrete can be adjusted according to the application and desired specific properties. The performance of abrasion resistance of concrete with 20% CRTS is especially notable. Research is needed on concrete with more than 20% CRTS. Furthermore, the use of CRT funnels in concrete is also an important matter because of their lead content. Lead is harmful to the environment. In this respect, recycling of CRT funnels is important, and

The study is notable in terms of the potential use of recycled CRTS because of the quantity of waste CRTS used. Concrete properties can be improved with CRTS, resulting in the reduction

The author wishes to acknowledge the support of Prof. Dr. Christian Meyer (who has patented the "use of waste glass in concrete") from the Civil Engineering and Engineering Mechanics Department at Columbia University, who contributed important ideas to this study during a research on internal curing of concrete with the author in Carleton Laboratory at Columbia

[1] Özkan Ö. Properties of mortars containing waste bottle glass and blast furnace slag. Journal of the Faculty of Engineering and Architecture of Gazi University. 2007;22(1):87-

[2] Shayan A, Xu A. Value-added utilisation of waste glass in concrete. Cement and Concrete

decrease is approximately 2.5%.

there is a need for research on this subject.

Acknowledgements

University.

Author details

Salih Taner Yildirim

References

of piles of waste CRTs when they are used in concrete.

Address all correspondence to: styildirim@kocaeli.edu.tr

94. DOI: 10.1016/j.conbuildmat.2007.01.015

Department of Civil Engineering, Kocaeli University, Kocaeli, Turkey

Research. 2004;34(1):81-89. DOI: 10.1016/S0008-8846(03)00251-5

## 4. Conclusions

Based on the results of the experimental studies carried out in the research, the results obtained are presented below:


7. The abrasion volume loss (%) decreases with increasing CRTS content up to 20%. The decrease is approximately 2.5%.

In conclusion, the concrete with CRTS aggregate exhibits a performance similar to that of the concrete without CRTS. This result shows that the use of CRTS can contribute to the properties of concrete. The mixture of CRTS in concrete can be adjusted according to the application and desired specific properties. The performance of abrasion resistance of concrete with 20% CRTS is especially notable. Research is needed on concrete with more than 20% CRTS. Furthermore, the use of CRT funnels in concrete is also an important matter because of their lead content. Lead is harmful to the environment. In this respect, recycling of CRT funnels is important, and there is a need for research on this subject.

The study is notable in terms of the potential use of recycled CRTS because of the quantity of waste CRTS used. Concrete properties can be improved with CRTS, resulting in the reduction of piles of waste CRTs when they are used in concrete.
