Abstract
Whenever a new material is replaced in concrete, some other tests other than strength and durability need to be carried out to validate the viability of the material replaced. This study aims to investigate the sustaining capacity of the light weight concrete manufactured with compost and Ground Granulated Blast Furnace Slag (GGBS) for M sand and cement respectively subjected to high temperature. Four concrete samples are tested, which includes the control specimen and three specimens are opted based on the optimum mix arrived from the strength and durability studies. Thermogravimetric Analysis (TGA) is done on the samples and they are heated up to 1,000 °C. For the specimens tested, the loss in mass with respect to the temperature is obtained. It is noted that the mass loss of the concrete samples with 15% GGBS along with compost at 0 & 10% is found lower than the control specimen. Also, from the loss in mass, the loss of chemically bound water and free CH content can be found, which aids in contributing strength to the concrete. For the concrete to be sustainable, compost can be replaced at 10% and GGBS at 15%.
1 Introduction
Concrete is a composite element that mainly consists of cement, fine aggregate, coarse aggregate, and water. As studying the mechanical and durability properties of concrete, it is essential to know the thermal behavior of the concrete to ensure the safety and serviceability of the structure. Fire accidents occur due to manmade or natural causes which affect human life and property [1]. Even though concrete is known to be a fire proof material, the concrete tends to degrade at elevated temperatures causing severe damage to the structure [2]. So, thermal load needs to be considered in bulk concrete structures.
Thermal studies are done in concrete to analyze the behavior of the concrete at a higher temperature when it is exposed to fire. The concrete, which is vulnerable to thermal stress, will damage the structure over time. Depending on the temperature and their exposure time to fire, the structures are subjected to failure both in the short and long term. To know the thermal stability of the concrete, various methods are available such as Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Thermal Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) etc. [3].
The TGA method is the one in which the thermal behavior of the material is characterized by mass loss of the samples due to thermal decomposition [4, 5]. The temperature in the furnace increases at a constant rate, and the compounds present in the sample decompose and induce a reduction in the mass of the sample [6]. The various compounds present in the concrete sample decompose at various temperature. For instance, when the temperature is about 100 to 120 °C, the moisture held inside gets evaporated completely. The ettringite and gypsum present in cement will decompose at about 170 °C. When the temperature in the sample reaches around 300 °C, the carboaluminate hydrate and the Calcium Silicate Hydrate (CSH) start to decompose [6]. When the temperature reaches around 550 °C, the Calcium Hydroxide (Ca(OH)2) decomposes by producing CaO and H2O. This reaction is known as the dehydroxylation of calcium hydroxide. Chemical changes may take place in the aggregate when the temperature in the chamber goes beyond 600 °C [2]. The calcium hydroxide present in the sample will get completely decomposed when the temperature reaches above 700 °C [7]. When the temperature reaches 700 to 900 °C, the calcium carbonate gets decarbonated.
Various studies are carried out on cement mortar and concrete to assess the thermal effect on them when the concrete is exposed to fire. Some studies are carried out directly on the cement mortar and the conventional concrete. [6] carried out a thermal study on cement mortar in which the sample was heated up to 800 °C to identify the decomposition of various elements. The concrete manufactured with M20 grade is exposed to a higher temperature of 1,000 °C and the decomposition of the concrete sample is studied [7]. Concrete manufactured with waste electronic plastic replaced at 10, 15, and 20% for natural sand and silica fume replaced at 10, 15, and 20% for cement is tested for TGA and the samples are heated till 800 °C and it is found that the concrete containing plastic aggregate had an inferior performance than the control specimen [8]. Waste tire rubber particles irradiated with gamma rays is replaced for cement at 1, 3, and 5% for cement and the concrete is studied for its mechanical and microstructural properties. The samples are heated up to 450 °C while performing TGA and the properties of the concrete are observed when gamma rays are irradiated on the waste tire rubber particles [9]. Studies are also done by adding admixtures to the cement paste and concrete. Mineral admixtures such as tuff, limestone filler, and granodiorite are added to the cement paste and it is found that the mineral admixtures contribute greater strength and it lowers the non-evaporable water content [10]. Thermal analysis is carried out on the concrete samples containing alccofine replaced at 25% for cement with the concrete having various water binder ratios and it is concluded that alccofine can be a viable option to replace cement in normal concrete [11]. TGA is done on concrete columns with Fiber Reinforced Polymer (FRP) and they were exposed to elevated temperatures of up to 400 °C to know the decomposition of epoxy. It is observed that the epoxy starts to decompose at 342 °C [12]. In self-compacting concrete, LaSrCoO3 oxides are added at 2% and when they are exposed to elevated temperatures of about 900 °C, the loss in mass is found to be less than the control specimen without LaSrCoO3 oxides in it [13].
When sustainable or waste materials are used in the concrete, studies like mechanical, durability, and thermal studies need to be carried out. In this study, TGA is done for the light weight concrete manufactured with compost replaced for M sand and Ground Granulated Blast Furnace Slag (GGBS) replaced for cement at various percentages. It is known that compost is a secondary byproduct attained from the decomposition of solid waste. In India, still more organic waste is unutilized and sent to dumping in open yards or disposal without treatment [14]. So, compost is replaced for M sand in the manufacturing of lightweight concrete. Previous investigations [15] focused on the strength parameter of the concrete by replacing compost and GGBS for M sand and cement respectively. Current investigation focuses on the thermal behavior of the optimal concrete mixes arrived from the strength and durability studies.
As with other studies such as strength and durability, the thermal study is also a key study that needs to be carried out on the concrete sample. As compost is added as a replacement material for M sand and the GGBS for cement, it is necessary to perform thermal studies to know the effect of these materials on the concrete samples when they are subjected to higher temperatures. So, the main objective of this study is (i) To know whether the addition of compost will deteriorate the concrete when it is subjected to elevated temperatures. (ii) To determine the optimum percentage of compost and GGBS replaced in the concrete without compromising the concrete properties. (iii) To study whether the addition of GGBS aids in the concrete properties when it is subjected to elevated temperature.
2 Materials and methods
2.1 Materials
In the manufacturing of light weight concrete, Ordinary Portland Cement of grade 53 is used. Locally available M sand is used as fine aggregate and it is procured nearby whereas pumice stone is used as coarse aggregate. GGBS is replaced at 0, 5, 10, and 15% for cement which is procured from JSW cements, and compost is replaced at 0, 10, 20, 30, 40, and 50% for M sand. Compost is collected from the university campus which is manufactured by collecting the wastes generated inside the campus. The concrete samples are casted by initially mixing the fine and coarse aggregate homogeneously and then cement is added to it and mixed well. Then the desired water content arrived from the mix design is added to it and it is mixed well to form a homogeneous paste. The concrete prepared is placed in moulds of 10 × 10 cm in three layers and each layer is compacted well and they are demoulded after 24 h. Then the casted specimens are kept in water for curing for a period of 28 days. After 28 days, the concrete samples are prepared into fine powder to test for the thermal study. The concrete samples are tested for strength and durability earlier, and the ideal mix is determined based on the test results. TGA is performed on those concrete samples. The sample preparation process is depicted in Figs 1 and 2 shows the specimens tested for TGA whereas Table 1 contains information about the specimen tested for TGA and Table 2 shows the mix design adopted in casting the concrete specimens.
Flowchart of sample preparation
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
Casted specimens for thermal study
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
Specimen details used for TGA
| S. No. | Specimen name | Cement % | GGBS % | M sand % | Compost % | Pumice % |
| 1 | LC-G0-C0 (Control specimen) | 100 | 0 | 100 | 0 | 100 |
| 2 | LC-G10-C10 | 90 | 10 | 90 | 10 | 100 |
| 3 | LC-G15-C0 | 85 | 15 | 100 | 0 | 100 |
| 4 | LC-G15-C10 | 85 | 15 | 90 | 10 | 100 |
Note: LC – Light weight Concrete G – GGBS percentage and C – compost percentage.
Mix proportion of the concrete specimens (kg m−3)
| Specimen | Cement | GGBS | M sand | Compost | Pumice stone | Water |
| LC-G0-C0 | 428.32 | 0 | 805.47 | 0 | 391.80 | 284.94 |
| LC-G10-C10 | 385.59 | 42.84 | 724.93 | 80.54 | 391.80 | 284.94 |
| LC-G15-C0 | 364.08 | 64.24 | 805.47 | 0 | 391.80 | 284.94 |
| LC-G15-C10 | 364.08 | 64.24 | 724.93 | 80.54 | 391.80 | 284.94 |
2.2 Methods
The main principle of TGA is the decomposition of the sample by heating the sample at higher temperatures at a constant rate in which the mass loss is measured. The temperature and mass of the sample are measured in a controlled atmosphere. The thermal properties of the concrete samples in this study are examined using a NETZSCH Thermogravimetric analyzer. The sample is placed in a sample chamber or pan attached to a sample holder and linked to a microbalance. Normally, the chamber pan is made up of platinum, alumina, and aluminium, so that they do not react with the samples. The equipment has a customized temperature program in which the temperature variation can be set. The sample is kept in the chamber and heated till it reaches 1,000 °C with the help of an electric furnace. The entire test takes place with the flow of nitrogen purge of 100 ml min−1. The loss in mass of the sample is recorded periodically at 5 °C min−1. From the loss of mass, the decomposition of components from the samples at different temperatures can be known. While recording the loss in mass, the temperature difference between the test sample and the reference sample is recorded simultaneously. It is known as Differential Thermal Analysis (DTA). From the DTA, the thermal reaction that took place under various temperatures can be analyzed. Any reversible reaction seen in the graph signifies that it is due to the thermal effect such as phase transition or decomposition. Both TGA and DTA can be plotted in the same graph.
With the mass loss results, the chemically bound water and free Calcium Hydroxide (CH) content present in the concrete can also be analyzed. The chemically bound water is the one which is present in the solid concrete matrix and it helps the concrete to attain strength during and after curing period. The free CH content in the concrete aids in the increase in pozzolanic reaction and contributes strength to the concrete. The performance of the concrete in the long term can be analyzed based on the chemically bound water and the free CH content present in it.
Ldh = mass loss between 105 and 440 °C due to dehydration of the hydrates (%)
Ldx = mass loss between 440 and 580 °C due to dehydroxylation of calcium hydroxide (%)
Ldc = mass loss between 580 and 1,000 °C due to decarbonation of calcite and the anhydrous material (%)
3 Results and discussion
3.1 Loss in mass
From Fig. 3, the X axis shows the temperature range adopted in the study and the Y axis shows the % mass loss of the samples. The mass loss of all the concrete samples with respect to the increase in the temperature is shown in Fig. 3. From Fig. 3, it can be observed that the loss in mass of the concrete specimen with GGBS at 15% & compost at 0% (LC-G15-C0) and the specimen with GGBS and compost at 15% & 10% (LC-G15-C10) respectively, is found to be lower that the control specimen (LC-G0-C0). It is known that adding compost along with GGBS has shown more reduction in loss in mass than the control specimen. So, compost can be replaced up to 10% in the concrete.
TGA of concrete samples
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
As compost is used in the study, to know the decomposition of the organic matter in the concrete samples the test data is divided in to three phases 0–300, 300–700, and 700–1,000 °C and the organic matter decomposition takes place in the second phase. The loss of mass of the specimens in the corresponding three phases is given in Table 3 while Fig. 4 illustrates the mass loss of all the specimens in the three phases.
Mass loss of the concrete samples
| Specimen | Mass loss in % | ||
| Phase 1 (0–300°) | Phase 2 (300–700°) | Phase 3 (700–1,000°) | |
| LC-G0-C0 (Control specimen) | 3.92 | 4.36 | 2.22 |
| LC-G10-C10 | 6.4 | 3.73 | 1.7 |
| LC-G15-C0 | 4.19 | 3.99 | 1.62 |
| LC-G15-C10 | 3.87 | 3.89 | 2.05 |
Phase wise mass loss of the concrete samples
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
From Fig. 4, the loss in mass of the control specimen in the three phases is noted to be 3.92, 4.36, and 2.22%, respectively. Similarly, the loss of mass of the sample with GGBS at 10% and compost at 10% in the corresponding three phases are 6.4, 3.73, and 1.7%, respectively whereas for the specimen with GGBS alone replaced at 15%, the loss in mass is noted to be 4.19, 3.99, and 1.62%, respectively and when the GGBS is replaced at 15% and compost replaced at 10% the loss in mass is 3.87, 3.89 and 2.05%, respectively.
In the first phase, it is noted that the mass loss of all the samples took place due to the evaporation of the moisture and in this phase, the CSH gel from the concrete gets decomposed [6, 17, 18]. At this stage when the CSH gets decomposed completely, the concrete structure breaks down and affects the performance of the concrete. When compost is added at 10% in the concrete, the mass loss of the sample is found higher than the control specimen. So, the GGBS content is increased to 15% with 0% compost and the mass loss tends to get reduced. Along with 15% GGBS when compost is added at 10%, the mass loss is found to be 3.87%, which is slightly lower than the mass loss of the control specimen. So, the presence of compost along with GGBS did not show a higher loss in mass of the sample.
In the second phase, the loss in mass of all the samples is found to be slightly lower than the mass loss of the control specimen, even though compost is present in the sample. In this phase, the organic matter present in the compost will get decomposed completely. The calcium hydroxide present in the concrete samples gets decomposed in this phase, which leads to the increase in the porosity of the concrete and deteriorates it. Overall, in this phase, the organic matter present in the compost and the calcium hydroxide present in the concrete gets decomposed.
In the third phase the mass loss of all the specimens tends to be lower than the control specimen. In this phase, though only the inorganic residues are left in the concrete sample, decomposition of calcium carbonate occurs leaving behind calcium oxide. The concrete will eventually show a reduction in volume which leads to its weakening and degradation. These are the reactions that occurred in the concrete sample when they are subjected to elevated temperature.
The overall mass loss and the percentage of residues left on the samples are shown in Table 4.
Percentage of total residues left
| S. No | Sample | Mass loss % | % Residues left |
| 1 | LC-G0-C0 | 10.51 | 89.49 |
| 2 | LC-G10-C10 | 11.83 | 88.17 |
| 3 | LC-G15-C0 | 9.80 | 90.20 |
| 4 | LC-G15-C10 | 9.81 | 90.19 |
To study the effect of GGBS with compost and without compost, the results obtained in Table 4 are presented in Fig. 5 and they are discussed based on two criteria. In the first case, the concrete specimen without GGBS and with 15% GGBS is compared and discussed whereas in the second case, the percentage of GGBS is kept constant at 15% and the compost is varied at 0 and 10% and the results are discussed.
Mass loss for control and GGBS at 15%
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
From Fig. 5, the total loss of mass of the control specimen is 10.51%, whereas when GGBS is replaced to it at 15%, the loss of mass is found to be 9.80%. It is evident that the mass loss of the specimen is reduced when GGBS is replaced for cement at 15%. So, the addition of GGBS binds well in the concrete and increases the pozzolanic reaction [16] thus aids in lowering the loss of mass.
Also, in the case when GGBS is added at 15% in both the specimens, when the percentage of compost is 0, the loss in mass is 9.80%, whereas when the percentage of the compost is increased to 10%, the loss in mass is found to be 9.81%. As there is no significant difference in the loss in mass of the samples, it can be understood that the presence of compost did not contribute to higher loss in mass. Thus, compost can be added to the concrete along with GGBS for the concrete to be sustainable.
3.2 Differential Thermal Analysis (DTA)
From Fig. 6, the Y axis shows the heat flow measured during the test. From the figure, it can be observed that there are some reverse in the peaks in the DTA, which are called the exothermic peaks, which occur due to decomposition or any other changes in the sample. The change in peak for the samples is seen from the graph and the temperature at which it took place is presented in Table 5.
DTA of concrete samples tested
Citation: International Review of Applied Sciences and Engineering 15, 2; 10.1556/1848.2023.00724
Temperature of the exothermic peaks
| S. No | Specimen | Temperature at which the exothermic peaks occurred |
| 1. | LC-G0-C0 | 109.3, 449.3, 579.3 and 754.3 °C |
| 2. | LC-G10-C10 | 294.4, 489.4, 734.4 and 919.4 °C |
| 3. | LC-G15-C0 | 524.4, 829.4, 959.4 °C |
| 4. | LC-G15-C10 | 935.1 °C |
In the control specimen, the exothermic peak is seen to be noted at 4 different temperature levels at 109.3, 449.3, 579.3 and 754.3 °C. The reversible reaction at 109.3 °C is due to the free water present in the concrete, which gets evaporated at this temperature. The second and third peaks at 449.3 and 579.3 °C occurred due to the reversible reaction of the decomposition of the calcium hydroxide. At this temperature, the calcium hydroxide decomposes to calcium oxide thus weakening the concrete. The reversible reaction at peak 754.3 °C signifies the decomposition of calcium carbonate in the sample. After 754.3 °C, only inorganic compounds are left in the concrete.
For the specimens with GGBS and compost at 10%, the exothermic peak occurs at 294.4, 489.4, 734.4 and 919.4 °C. The reversible reaction at 294.4 °C, the decomposition of CSH gel takes place. This decomposition of the CSH gel leads to the breakdown of the concrete structure and it starts to lose its properties. The temperature at 489.4 °C may denote the dehydroxylation reaction of calcium hydroxide whereas at 734.4 and 919.4 °C, the decarbonation of calcium carbonate may take place. At higher temperatures, when the decarbonation takes place, the concrete structure will get deteriorated.
Similarly, for the specimen with 15% GGBS replaced for cement, the exothermic peaks occur at 524.4, 829.4, and 959.4 °C. The exothermic peak at 524.4 °C, the portlandite may get decomposed and it may lead to an increase in porosity in the concrete thus affecting the performance of the concrete. At 829.4 & 959.4 °C, the decarbonation reaction takes place. The specimen with GGBS at 15% and compost at 10%, a steady flow has taken place, and an exothermic peak is observed at 935.1 °C only and it may be due to the decarbonation reaction.
3.3 Loss of chemically bound water
The water held in between the concrete compounds can be known as the chemically bound water [10]. The chemically bound water plays a significant role in providing strength to the concrete at later days. When the concrete is exposed to an elevated temperature of 600–800 °C, the bound water may get lost which directly reduces the strength of the concrete and it may lead to an increase in the porosity of the concrete thus damaging it [7]. The chemically bound water is present in the hydrated phases of the sample, which will be removed after the decomposition of the hydrates present in the sample. Apart from this, removing this water by other means such as drying can cause shrinkage in the microstructure [19].
The percentage of chemically bound water held in the samples is calculated based on equation (1) and is provided in Table 6.
Loss of chemically bound water
| Specimen detail | Mass loss (%) | Loss of chemically bound water (WB) % | ||
| Ldh | Ldx | Ldc | ||
| LC-G0-C0 | 3.753 | 1.261 | 4.038 | 6.669 |
| LC-G10-C10 | 5.391 | 1.525 | 2.734 | 8.036 |
| LC-G15-C0 | 3.861 | 1.132 | 3.149 | 6.284 |
| LC-G15-C10 | 3.781 | 1.090 | 3.600 | 6.347 |
From Table 6, the chemically bound water present in the control specimen is 6.669%. For the sample with compost and GGBS at 10%, the chemically bound water is 8.036%, which is found slightly higher than the control specimen. So, after increasing the GGBS content to 15%, for the specimen containing GGBS alone at 15%, the bound water is 6.284% and for the specimen with GGBS @ 15% and compost @ 10%, the bound water is 6.347%. From this, it can be observed that initially when GGBS is added at 10% along with 10% compost, the bound water tends to be higher than the control specimen. Whereas when the GGBS percentage is increased to 15%, with compost at 0 & 10% respectively, the bound water content is found slightly lower than the control specimen. So, it is evident that the replacement of compost does not affect the bound water content present in the sample.
3.4 Loss of free calcium hydroxide (CH) content
The Calcium Hydroxide (CH) can be present at 5–20% in the concrete, if it is present in excess, it affects the strength and serviceability of the concrete and may lead to damage. So, the free CH present in the sample can be evaluated from the TGA results.
The free CH present in the sample tested are calculated based on equation (2) and presented in Table 7.
Loss of free calcium hydroxide
| Specimen | Free CH % |
| LC-G0-C0 | 11.965 |
| LC-G10-C10 | 10.860 |
| LC-G15-C0 | 9.942 |
| LC-G15-C10 | 10.527 |
It is seen from Table 7 that the amount of free CH is less in the samples with GGBS than the control specimen and it is also found to be within the limits. It is due to the presence of the cementitious materials which increases the pozzolanic reaction thus lowering the free CH content [16]. Here the presence of GGBS in the concrete increases the pozzolanic reaction thereby increasing the CSH gel thus minimizing the free CH content.
4 Conclusion
When a sustainable material compost is incorporated in concrete, it is essential to know how the material will behave under elevated temperature in order to ensure the performance of the concrete. So, from the current investigation, the decomposition of various elements of the concrete made with GGBS and compost at higher temperatures can be found. In this study, the concrete specimens are subjected to an elevated temperature of up to 1,000 °C and they are analyzed by means of thermal study (TGA). The following observations were made from the analysis of results from TGA.
The total mass loss of the control specimen is 10.5%, the specimen with both GGBS and compost at 10% have mass loss of 11.83%, the mass loss of the concrete specimen with GGBS 15% is found to be 9.80% and the loss in mass of the specimen with GGBS 15% and compost 10% is 9.81%. Overall, the specimens containing GGBS at 15% showed lower loss of mass than the control specimen. Also, the presence of the compost in the concrete did not significantly affect the concrete.
The exothermic peaks are the ones that arrived due to the reversible reaction that took place while heating the concrete at higher temperatures. The specimen with GGBS and compost at 15% and 10% respectively had a steady flow throughout the entire heating.
The chemically bound water for the samples with 15% GGBS with compost at 0 & 10% respectively is found less than the control specimen.
The free Calcium Hydroxide content is also calculated from the mass loss and it is noted that the free CH content of all the samples tested is found less than the control specimen. Hence it may be due to the presence of GGBS increasing the pozzolanic reaction in the sample.
Overall, the samples containing GGBS at 15% showed lower mass loss and adding compost to it at 10% did not contribute to higher mass loss in the sample. The chemically bound water and the free CH of the samples with 15% GGBS are found to be lower than the control specimen. The addition of compost along with GGBS does not significantly affect the concrete.
As the concrete specimens are casted with compost which is organic in nature, the TGA stands to be an ideal method for assessing the decomposition of the organic matter at elevated temperatures. Moreover, the samples tested for TGA are in powder form, so, the strength and durability of the samples cannot be found. In subsequent research, this study can be extended by casting concrete specimens and testing for the strength and durability following the exposure to elevated temperatures.
References
- [1]↑
K. V. Teja and T. Meena, “An insight into temperature characteristics of ternary blended concrete with perlite powder,” Asian J. Civ Eng., vol. 21, pp. 41–8, 2020. https://doi.org/10.1007/s42107-019-00179-1.
- [2]↑
B. Chen, C. Li, and L. Chen, “Experimental study of mechanical properties of normal-strength concrete exposed to high temperatures at an early age,” Fire Saf. J, vol. 44, no. 7, pp. 997–1002, 2009. https://doi.org/10.1016/j.firesaf.2009.06.007.
- [3]↑
S. Vyazovkin and N. Sbirrazzuoli, “Isoconversional kinetic analysis of thermally stimulated processes in polymers,” Macromol Rapid Comm., vol. 27, no. 18, pp. 1515–32, 2006. https://doi.org/10.1002/marc.200600404.
- [4]↑
R. B. Prime, H. E. Bair, S. Vyazovkin, P. K. Gallagher, and A. Riga, “Thermogravimetric analysis (TGA). Thermal analysis of polymers: Fundamentals and applications,” vol. 1, pp. 241–317, 2009.
- [5]↑
C. De Blasio and C. De Blasio, “Thermogravimetric analysis (TGA),” Fundamentals Biofuels Eng. Tech., pp. 91–102, 2019. https://doi.org/10.1007/978-3-030-11599-9_7.
- [6]↑
L. Alarcon-Ruiz, G. Platret, E. Massieu, and A. Ehrlacher, “The use of thermal analysis in assessing the effect of temperature on a cement paste,” Cem. Concre. Res., vol. 35, no. 3, pp. 609–13, 2005. https://doi.org/10.1016/j.cemconres.2004.06.015.
- [7]↑
S. K. Handoo, S. Agarwal, and S. K. Agarwal, “Physicochemical, mineralogical, and morphological characteristics of concrete exposed to elevated temperatures,” Cem. Concre. Res., vol. 32, no. 7, pp. 1009–18, 2002. https://doi.org/10.1016/S0008-8846(01)00736-0.
- [8]↑
K. Ali, M. I. Qureshi, S. Saleem, and S. U. Khan, “Effect of waste electronic plastic and silica fume on mechanical properties and thermal performance of concrete,” Construct. Build. Mater., vol. 285, 2021, Art no. 122952. https://doi.org/10.1016/j.conbuildmat.2021.122952.
- [9]↑
G. Martínez-Barrera, J. J. del Coz-Díaz, F. P. Álvarez-Rabanal, F. L. Gayarre, M. Martínez-López, and J. Cruz-Olivares, “Waste tire rubber particles modified by gamma radiation and their use as modifiers of concrete,” Case Stud. Construct. Mater., vol. 12, 2020, Art no. e00321. https://doi.org/10.1016/j.cscm.2019.e00321.
- [10]↑
M. Meziani, N. Chelouah, O. Amiri, and N. Leklou, “Blended cement hydration assessment by thermogravimetric analysis and isothermal calorimetry,” in InMATEC Web of Conferences, vol. 149, EDP Sciences, 2018, p. 01062. https://doi.org/10.1051/matecconf/201814901062.
- [11]↑
P. Narasimha Reddy and J. Ahmed Naqash, “Experimental study on TGA, XRD and SEM analysis of concrete with ultra-fine slag,” Int. J. Eng., vol. 32, no. 5, pp. 679–684, 2019.
- [12]↑
L. Joseph, M. K. Madhavan, K. Jayanarayanan, and A. Pegoretti, “High temperature performance of concrete confinement by MWCNT modified epoxy based fiber reinforced composites,” Materials, vol. 15, no. 24, p. 9051, 2022. https://doi.org/10.3390/ma15249051.
- [13]↑
A. Bahari, A. Sadeghi-Nik, F. U. Shaikh, A. Sadeghi-Nik, E. Cerro-Prada, E. Mirshafiei, and M. Roodbari, “Experimental studies on rheological, mechanical, and microstructure properties of self-compacting concrete containing perovskite nanomaterial,” Struct. Concrete, vol. 23, no. 1, pp. 564–78, 2022. https://doi.org/10.1002/suco.202000548.
- [14]↑
T. V. Ramachandra, H. A. Bharath, G. Kulkarni, and S. S. Han, “Municipal solid waste: generation, composition and GHG emissions in Bangalore, India,” Renew. Sustain. Energy Rev., vol. 82, pp. 1122–36, 2018. https://doi.org/10.1016/j.rser.2017.09.085.
- [15]↑
K. P. Pandiaraj, V. Sankararajan, and M. Palaniappan, “Utilization of compost and GGBS in the manufacturing of light-mass concrete—characteristics and mechanical properties,” Environ. Sci. Pollut. Res., vol. 29, no. 25, pp. 38026–37, 2022. https://doi.org/10.1007/s11356-022-18782-2.
- [16]↑
S. M. Monteagudo, A. Moragues, J. C. Gálvez, M. J. Casati, and E. Reyes, ““The degree of hydration assessment of blended cement pastes by differential thermal and thermogravimetric analysis” Morphological evolution of the solid phases,” Thermochim. Acta, vol. 592, pp. 37–51, 2014. https://doi.org/10.1016/j.tca.2014.08.008.
- [17]↑
E. Nonnet, N. Lequeux, and P. Boch, “Elastic properties of high alumina cement castables from room temperature to 1600 C,” J. Eur. Ceram. Soc., vol. 19, no. 8, pp. 1575–1583, 1999. https://doi.org/10.1016/S0955-2219(98)00255-6.
- [18]↑
G. A. Khoury, “Compressive strength of concrete at high temperatures: a reassessment,” Mag. Concre. Res, vol. 44, no. 161, pp. 291–309, 1992. https://doi.org/10.1680/macr.1992.44.161.291.
- [19]↑
D. Snoeck, L. F. Velasco, A. Mignon, S. Van Vlierberghe, P. Dubruel, P. Lodewyckx, and N. De Belie, “The influence of different drying techniques on the water sorption properties of cement-based materials,” Cem. Concre. Res., vol. 64, pp. 54–62, 2014. https://doi.org/10.1016/j.cemconres.2014.06.009.
