scholarly journals Cement-Based Renders Manufactured with Phase-Change Materials: Applications and Feasibility

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Luigi Coppola ◽  
Denny Coffetti ◽  
Sergio Lorenzi
Keyword(s):  
Compressive Strength ◽  
Phase Change ◽  
Phase Change Materials ◽  
Residential Buildings ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Hydration Kinetics ◽  
Mechanical Performances ◽  
Entrapped Air ◽  
Kinetics Of

The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM) in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.

scholarly journals Thermodynamics and kinetics of glassy and liquid phase-change materials

2021 ◽  
Vol 135 ◽  
pp. 106094
Author(s):  
Narges Amini ◽  
Julian Pries ◽  
Yudong Cheng ◽  
Christoph Persch ◽  
Matthias Wuttig ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Phase Change Materials ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of

scholarly journals Effectiveness of Using Phase Change Materials on Reducing Summer Overheating Issues in UK Residential Buildings with Identification of Influential Factors

Energies ◽  
2016 ◽  
Vol 9 (8) ◽  
pp. 605 ◽  
Author(s):  
Marine Auzeby ◽  
Shen Wei ◽  
Chris Underwood ◽  
Jess Tindall ◽  
Chao Chen ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Residential Buildings ◽  
Influential Factors

Phase Change Materials - From Structures to Kinetics

2006 ◽  
Vol 918 ◽  
Author(s):  
Matthias Wuttig ◽  
Wojciech Welnic ◽  
Ralf Detemple ◽  
Henning Dieker ◽  
Johannes Kalb ◽  
...  
Keyword(s):  
Phase Change ◽  
Crystalline State ◽  
Phase Change Materials ◽  
Amorphous State ◽  
Structural Difference ◽  
Fast Time ◽  
Optical Contrast ◽  
Fast Time Scale ◽  
Kinetics Of ◽  
Structure Properties

AbstractPhase change materials possess a unique combination of properties which include a pronounced property contrast between the amorphous and crystalline state, i.e. a high electrical and optical contrast. In particular the latter observation is indicative for a considerable structural difference between the amorphous and crystalline state. At the same time the crystallization of the amorphous state proceeds on a fast time scale. This raises the question how structure, properties and kinetics are related in phase change alloys. It will be demonstrated that only a small group of covalent semiconductors with octahedral-like coordination has the required property combination. This is related to their thermodynamic properties which govern the kinetics of crystallization.

scholarly journals Thermo-physical characteristics of building integrated phase change materials (PCM) and their applicability to energy efficient homes

2021 ◽  
Author(s):  
Omar Siddiqui
Keyword(s):  
Compressive Strength ◽  
Phase Change ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Physical Characteristics ◽  
Comfort Level ◽  
Thermal Mass ◽  
Lower Phase ◽  
Physical Test ◽  
The Impact

The applicability of utilizing a variety of thermal mass including phase change materials with commonly used building materials is investigated through the use of simulations and physical testing. The thermal performance and occupant comfort potential of a novel solid-solid phase change material, known as Dal HSM, is compared and contrasted to commonly available forms of thermal mass. Detailed experimentation is conducted to successfully integrate Dal HSM with gypsum and concrete. The measurement of physical characteristics such as compressive strength and modulus of rupture is conducted to ensure that the PCM-composite compound retains the structural integrity to be utilized in a typical building. The use of thermal mass in the Toronto Net Zero house was found to contribute to energy savings of 10-15% when different types of thermal mass were used. The comfort level of the indoor occupants was also found to increase. The performance of Dal HSM was found to be comparable to a commercially available PCM known as Micronal in the heating mode. The cooling mode revealed that Dal HSM provided slightly lower energy savings when compared to Micronal due to a lower phase transition temperature and latent heat. The performance of physical test revealed a decrease in the compressive strength as the concentration of Dal HSM was increased in the PCM-gypsum specimens. Tests were also performed to analyze the impact of increasing the PCM concentration on the flexural strength of PCM-gypsum composite.

scholarly journals Effects of Expansive Agents on the Early Hydration Kinetics of Cementitious Binders

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1900 ◽  
Author(s):  
Miao Miao ◽  
Qingyang Liu ◽  
Jian Zhou ◽  
Jingjing Feng
Keyword(s):  
Fly Ash ◽  
Hydration Heat ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Hydration Reaction ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Expansive Agent ◽  
Mechanical Performances ◽  
Kinetics Of

The addition of expansive agents could overcome the main disadvantages of raw concrete including high brittleness and low tensile strength. Few studies have investigated the early hydration kinetics of expansive cementitious binders, though the findings from the early hydration kinetics are helpful for understanding their technical performances. In this study, mixtures of 3CaO•3Al2O3•CaSO4 and CaSO4 (i.e., ZY-type™ expansive agent) with different proportions of mineral admixtures (e.g., fly ash and slag) were added into cement pastes to investigate the early hydration kinetics mechanism of expansive cementitious binders. Early hydration heat evolution rate and cumulative hydration heat were measured by isothermal calorimeter. Kinetic parameters were estimated based on the Krstulovic–Dabic model and Knudsen equations. Mechanical performances of expansive cementitious binders were tested in order to evaluate if they met the basic requirements of shrinkage-compensating materials in technical use. The early hydration heat released from cementitious binders containing ZY-type™ expansive agent was much greater than that released by pure cement, supporting the idea that addition of the expansive agent would improve the reaction of cement. The early hydration kinetic rates were decreased due to the reactions of the mineral admixture (e.g., fly ash or slag) and the ZY-type™ expansive agent in the cement system. The hydration reaction of cementitious binders containing ZY-type™ expansive agent obeyed the Krstulovic–Dabic model well. Three processes are involved in the hydration reaction of cementitious binders containing ZY-type™ expansive agent. These are nucleation and crystal growth (NG), interactions at phase boundaries (I), and diffusion (D). The 14-day expansion rates of cementitious binders containing ZY-type™ expansive agent are in the range of 2.0 × 10−4 to 3.5 × 10−4, which could meet the basic requirements of anti-cracking performances in technical use according to Chinese industry standard JGJ/T 178-2009. This study could provide an insight into understanding the effects of expansive agents on the hydration and mechanical performances of cementitious binders.

scholarly journals PROPERTIES OF CEMENT PASTE AND CONCRETE CONTAINING CALCIUM CARBIDE WASTE AS ADDITIVE

2016 ◽  
Vol 36 (1) ◽  
pp. 26-31
Author(s):  
EN Ogork ◽  
TS Ibrahim
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Calcium Carbide ◽  
Linear Shrinkage ◽  
Hardened Concrete ◽  
Concrete Compressive Strength ◽  
Initial Setting Time ◽  
Standard Procedures

This paper assessed the effect of calcium carbide waste (CCW) as additive on the properties of cement paste and concrete. The CCW used was sourced from a local panel beating workshop. It was sundried and sieved through a 75 µm sieve and characterized by X-Ray Fluorescence (XRF) analytical method. The consistency, setting times and drying linear shrinkage of cement paste with CCW addition of 0, 0.25, 0.5, 0.75 and 1.0 %, respectively by weight of cement were investigated in accordance with standard procedures. The slump values of fresh concrete containing CCW as additive and of 1:2:4 mix ratio and water-cement ratio of 0.5 was determined. A total of sixty numbers of 150 mm cubes of hardened concrete were tested for compressive strength at 1, 3, 7, 28 and 56 days of curing in accordance with standard procedures. The concrete compressive strength was also modeled using Minitab statistical software based on linear regression technique. The results of the investigations showed that CCW was predominantly of calcium oxide (95.69 %) and a combined SiO2, Al2O3 and Fe2O3 content of 3.14 %. The addition of CCW in cement decreased drying shrinkage (100 %), initial setting time (78 %) and final setting time (57 %), but increased consistency (14 %) at 1.0 % CCW content. The addition of CCW in concrete also showed slight increase in slump (6.5 %) and increase in compressive strength with increase in CCW additive up to 0.5 % and decrease in compressive strength with further increase in CCW content. The 28 days compressive strength of concrete with 0.5 % CCW content was 6.4 % more than normal, while that of concrete with 1.0 % CCW content was 14.9 % less than normal. The compressive strength model of CCW-concrete was developed with R2 value of 0.830 and could be used to predict concrete compressive strength. http://dx.doi.org/10.4314/njt.v36i1.4

scholarly journals Effect of Cr6+ on the Properties of Alkali-Activated Slag Cement

2021 ◽  
Vol 8 ◽  
Author(s):  
Fu Bo ◽  
Cheng Zhenyun
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Cement Stone ◽  
Slag Cement ◽  
Hydration Kinetics ◽  
Alkali Activated Slag ◽  
Dual Beam ◽  
Press Method ◽  
Activated Slag ◽  
Alkali Activated

In order to investigate the effect of Cr6+ on the properties of alkali-activated slag cement (AAS), the effects of added dosage of Na2Cr2O4 on the setting time and compressive strength of AAS were measured. The leaching concentration of Cr6+ from AAS cement stone was measured using dual-beam UV-visible spectrophotometry. The effect of Na2Cr2O4 on the hydration kinetics of AAS cement was monitored by microcalorimetry and the corresponding kinetic parameters were analyzed. The pore solution from AAS was collected and analyzed using the high pressure press method. The effects of Na2Cr2O4 on the hydration products of AAS cement were observed and compared using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results showed that the AAS hydration process was markedly affected by Na2Cr2O4 dosage. The setting time of AAS pastes was increased and the compressive strength of cement stones was reduced with increasing dosage of Na2Cr2O4. With the development of AAS hydration, the leaching concentration of Na2Cr2O4 gradually decreased. Na2Cr2O4 did not affect the dissolution of slag particles, but impeded the formation of C-S-H gel. The Cr6+ was immobilized chemically in the form of needle-like CaCrO4 particles formed by the chemical reaction between Na2Cr2O4 and Ca2+ leaching from the slag.

scholarly journals Preparation and characterization of phase change energy storage gypsum

2020 ◽  
pp. 217-217
Author(s):  
Yichao Zhang ◽  
Ying Wang ◽  
Jinghai Zhou ◽  
Jian Huang ◽  
Xiaoxin Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
Loss Rate ◽  
Thermal Conductivity Coefficient ◽  
Mass Loss Rate ◽  
Capric Acid

The thermophysical properties of binary phase change materials with different ratios of capric acid and palmitic acid were studied by step cooling curve method and differential scanning calorimetry in this paper. Furthermore, the best adsorption materials and coating materials were selected by testing their mass adsorption rate and mass loss rate. Finally, the specific heat capacity, thermal conductivity coefficient and compressive strength of phase change energy storage gypsum (PCESG) was determined respectively, and the energy-saving effect of the PCESG in the wall is evaluated. The results show that the binary phase change materials can form a eutectic system. When the mass ratio of capric acid to palmitic acid is 7:3, the low eutectic point of the binary system is formed, and the crystallization temperature of system is 26?C. The adsorption capacity of expanded perlite is much larger than that of ceramsite, and the mass loss rate of the material coated by styrene acrylic emulsion is lower than that of EVA. The specific heat capacity of PCESG is about twice that of ordinary gypsum. With the addition of phase change materials, the thermal conductivity coefficient of PCESG decreases gradually, and the compressive strength of PCESG decreases gradually at the same time. Compared with ordinary gypsum, PCESG has better energy-saving performance.

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