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20 pages, 7139 KiB

Open AccessArticle

Estimating the Slope Safety Factor Using Simple Kinematically Admissible Solutions

by Kamil Bacharz, Magdalena Bacharz and Wiesław Trąmpczyński

Materials 2023, 16(22), 7074; https://doi.org/10.3390/ma16227074 - 7 Nov 2023

Cited by 1 | Viewed by 1095

Abstract

Determining soil and water conditions is essential for designing the optimal foundation and safely transferring loads, including the self-weight of structures, to the ground. Excessive or uneven settlement of the subsoil may ultimately lead to the formation of structural cracks in buildings or [...] Read more.

Determining soil and water conditions is essential for designing the optimal foundation and safely transferring loads, including the self-weight of structures, to the ground. Excessive or uneven settlement of the subsoil may ultimately lead to the formation of structural cracks in buildings or the loss of slope stability. In extreme cases, the damage results in structural failure. This paper presents the application of simple solutions from plasticity theory—an evaluation of the upper and lower bounds of the exact solution—to estimate the slope safety factor. It is demonstrated that simple kinematically admissible mechanisms for the non-associated flow rule provide solutions are close to those obtained from the traditional Fellenius method. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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21 pages, 18129 KiB

Open AccessEditor’s ChoiceArticle

The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems

by Ece Ezgi Teker Ercan, Andrzej Cwirzen and Karin Habermehl-Cwirzen

Materials 2023, 16(15), 5347; https://doi.org/10.3390/ma16155347 - 29 Jul 2023

Cited by 2 | Viewed by 1858

Abstract

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial [...] Read more.

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial replacement for Portland cement and precursors in alkali-activated systems. The aim of this study was to examine the effect of ground wood ash on the mechanical properties of alkali-activated mortars. Wood ash was incorporated as a 0 wt%, 10 wt% and 20 wt% partial replacement for ground granulated blast furnace slag (GGBFS). The wood ashes were ground in a planetary ball mill for 10 and 20 min. Sodium silicate (Na₂SiO₃), sodium carbonate (Na₂CO₃), and sodium hydroxide (NaOH) were used as alkali activators. The results demonstrated that ground wood ash improved the mechanical properties of alkali-activated systems compared to untreated wood ash. However, the incorporation of wood ash increased the porosity of the binder matrix. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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16 pages, 8063 KiB

Open AccessArticle

Gypsum-Based Humidity-Control Material: Preparation, Performance and Its Impact on Building Energy Consumption

by Xi Li and Maoyu Ran

Materials 2023, 16(15), 5211; https://doi.org/10.3390/ma16155211 - 25 Jul 2023

Cited by 3 | Viewed by 1798

Abstract

This paper introduces a new type of gypsum-based humidity-control material. The material combines gypsum–silica gel humidity-control material with 20% sepiolite powder activated by calcium chloride. Both experimental and simulation studies were conducted to assess its humidity-control performance. The experimental results indicate that gypsum-based [...] Read more.

This paper introduces a new type of gypsum-based humidity-control material. The material combines gypsum–silica gel humidity-control material with 20% sepiolite powder activated by calcium chloride. Both experimental and simulation studies were conducted to assess its humidity-control performance. The experimental results indicate that gypsum-based humidity-control material has the property of absorbing moisture in high-humidity environments and releasing moisture in low-humidity environments. Moreover, both environmental temperature and relative humidity (RH) have an impact on the material’s humidity-control performance. At a relative humidity of 97.4%, the maximum equilibrium moisture content of the material is 0.225 g/g, which is 1.4 times that of the gypsum–silica gel humidity-control material and 4.5 times that of pure gypsum material. The simulation results indicate that gypsum-based humidity-control material effectively mitigates indoor relative humidity fluctuations and maintains indoor air relative humidity within a narrow range. Furthermore, the material has the potential to reduce building energy consumption. This is especially evident under climate conditions with large temperature and relative humidity differences between day and night, such as in Beijing, Paris, and Atlanta. The maximum potential energy-saving rate in Beijing can reach up to 19.31%. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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18 pages, 6395 KiB

Open AccessArticle

Plate Load Tests of Soft Foundations Reinforced by Soilbags with Solid Wastes for Wind Farms

by Chenchen Zhang, Jie Liao, Yuchi Zhang and Liujiang Wang

Materials 2023, 16(11), 4173; https://doi.org/10.3390/ma16114173 - 3 Jun 2023

Cited by 2 | Viewed by 1679

Abstract

Soilbags are expandable three-dimensional geosynthetic bags made from high-density polyethylene or polypropylene. This study conducted a series of plate load tests to explore the bearing capacity of soft foundations reinforced by soilbags filled with solid wastes based on an onshore wind farm project [...] Read more.

Soilbags are expandable three-dimensional geosynthetic bags made from high-density polyethylene or polypropylene. This study conducted a series of plate load tests to explore the bearing capacity of soft foundations reinforced by soilbags filled with solid wastes based on an onshore wind farm project in China. The effect of contained material on the bearing capacity of the soilbag-reinforced foundation was investigated during the field tests. The experimental studies indicated that soilbag reinforcement with reused solid wastes could substantially improve the bearing capacity of soft foundations under vertical loading conditions. Solid wastes like excavated soil or brick slag residues were found to be suitable as contained material, and the soilbags with plain soil mixed with brick slag had higher bearing capacity than those with pure plain soil. The earth pressure analysis indicated that stress diffusion occurred through the soilbag layers to reduce the load transferred to the underlying soft soil. The stress diffusion angle of soilbag reinforcement obtained from the tests was approximately 38°. In addition, combining soilbag reinforcement with bottom sludge permeable treatment was an effective foundation reinforcement method, which required fewer soilbag layers due to its relatively high permeability. Furthermore, soilbags are considered sustainable construction materials with advantages such as high construction efficiency, low cost, easy reclamation and environmental friendliness while making full use of local solid wastes. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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18 pages, 8235 KiB

Open AccessArticle

Prediction of the Bending Strength of a Composite Steel Beam–Slab Member Filled with Recycled Concrete

by Mohammed Chyad Liejy, Ahmed W. Al Zand, Azrul A. Mutalib, Ali A. Abdulhameed, A. B. M. A. Kaish, Wadhah M. Tawfeeq, Shahrizan Baharom, Alyaa A. Al-Attar, Ammar N. Hanoon and Zaher Mundher Yaseen

Materials 2023, 16(7), 2748; https://doi.org/10.3390/ma16072748 - 29 Mar 2023

Cited by 7 | Viewed by 1847

Abstract

This study investigated the structural behavior of a beam–slab member fabricated using a steel C-Purlins beam carrying a profile steel sheet slab covered by a dry board sheet filled with recycled aggregate concrete, called a CBPDS member. This concept was developed to reduce [...] Read more.

This study investigated the structural behavior of a beam–slab member fabricated using a steel C-Purlins beam carrying a profile steel sheet slab covered by a dry board sheet filled with recycled aggregate concrete, called a CBPDS member. This concept was developed to reduce the cost and self-weight of the composite beam–slab system; it replaces the hot-rolled steel I-beam with a steel C-Purlins section, which is easier to fabricate and weighs less. For this purpose, six full-scale CBPDS specimens were tested under four-point static bending. This study investigated the effect of using double C-Purlins beams face-to-face as connected or separated sections and the effect of using concrete material that contains different recycled aggregates to replace raw aggregates. Test results confirmed that using double C-Purlins beams with a face-to-face configuration achieved better concrete confinement behavior than a separate configuration did; specifically, a higher bending capacity and ductility index by about +10.7% and +15.7%, respectively. Generally, the overall bending behavior of the tested specimens was not significantly affected when the infill concrete’s raw aggregates were replaced with 50% and 100% recycled aggregates; however, their bending capacities were reduced, at −8.0% and −11.6%, respectively, compared to the control specimen (0% recycled aggregates). Furthermore, a new theoretical model developed during this study to predict the nominal bending strength of the suggested CBPDS member showed acceptable mean value (0.970) and standard deviation (3.6%) compared with the corresponding test results. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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13 pages, 3634 KiB

Open AccessArticle

Effect of Low Nesquehonite Addition on the Hydration Product and Pore Structure of Reactive Magnesia Paste

by Run Shi, Yuehan Hao, Deping Chen and Wenxin Liu

Materials 2023, 16(6), 2445; https://doi.org/10.3390/ma16062445 - 18 Mar 2023

Cited by 2 | Viewed by 1776

Abstract

Reactive magnesia cement is considered an eco-efficient binder due to its low synthesis temperature and CO₂ absorption properties. However, the hydration of pure MgO–H₂O mixtures cannot produce strong Mg(OH)₂ pastes. In this study, nesquehonite (Nes, MgCO₃·3H₂ [...] Read more.

Reactive magnesia cement is considered an eco-efficient binder due to its low synthesis temperature and CO₂ absorption properties. However, the hydration of pure MgO–H₂O mixtures cannot produce strong Mg(OH)₂ pastes. In this study, nesquehonite (Nes, MgCO₃·3H₂O) was added to the MgO–H₂O system to improve its strength properties, and its hydration products and pore structure were analyzed. The experimental results showed that the hydration product changed from small plate-like Mg(OH)₂ crystals to interlaced sheet-like crystals after the addition of a small amount of Nes. The porosity increased from 36.3% to 64.6%, and the total pore surface area increased from 4.6 to 118.5 m²/g. At the same time, most of the pores decreased in size from the micron scale to the nanometer scale, which indicated that Nes had a positive effect on improving the pore structure and enhancing the compressive strength. Combined with an X-ray diffractometer (XRD), a Fourier transform infrared spectrometer (FTIR), and a simultaneous thermal analyzer (TG/DSC), the hydration product of the sample after Nes addition could be described as xMgCO₃·Mg(OH)₂·yH₂O. When Nes was added at 7.87 and 14.35 wt%, the x-values in the chemical formula of the hydration products were 0.025 and 0.048, respectively. These small x-values resulted in lattice and property parameters of the hydration products that were similar to those of Mg(OH)₂. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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15 pages, 5085 KiB

Open AccessArticle

Chloride Penetration of Recycled Fine Aggregate Concrete under Drying–Wetting Cycles

by Chunhong Chen, Lei Wang, Ronggui Liu, Jiang Yu, Hui Liu and Jinlong Wu

Materials 2023, 16(3), 1306; https://doi.org/10.3390/ma16031306 - 3 Feb 2023

Cited by 6 | Viewed by 1864

Abstract

Recycled fine aggregate (RFA) produced from concrete waste is commonly used in the construction industry; however, its use for structural concrete members has not been extensively studied. Moreover, its durability in a drying–wetting cycle environment still needs to be examined. In this study, [...] Read more.

Recycled fine aggregate (RFA) produced from concrete waste is commonly used in the construction industry; however, its use for structural concrete members has not been extensively studied. Moreover, its durability in a drying–wetting cycle environment still needs to be examined. In this study, the intrusion process of chloride in concrete under the drying–wetting cycles is experimentally characterized. Chloride penetration tests are carried out on concrete with the incorporation of different RFA replacement rates and mineral admixtures (i.e., fly ash and silica fume). The results show that the chloride penetration of recycled fine aggregate concrete (RFAC) is dependent upon the performance of the concrete itself, while the deterioration of chloride ion erosion resistance is due to the combined action of the replacement rate of RFA and the drying–wetting cycles. The incorporation of RFA degrades the properties of RFAC owing to its drawbacks in the degradation of interfacial properties of RFAC. Exposure to the drying–wetting cycle environment causes the content of free chloride ions in RFAC to increase initially before decreasing with the erosion depth, thereby showing an obvious convection zone and diffusion zone. The incorporation of the mineral admixture can effectively improve the compactness of the concrete microstructure and make concrete less susceptible to chloride ions ingress. RFAC mixed with 15% fly ash and 10% silica fume has a comparable resistance to chloride penetration as a natural aggregate concrete, which is a feasible method for the application of RFA. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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19 pages, 9485 KiB

Open AccessArticle

Investigation on the Carbonation Behavior of Alkali-Activated Pastes Served under Windy Environments

by Dong Cui, Lingshu Shen, Yidong Shen, Guantong Han, Xiaoying Xie, Qianfei Cao, Jing Wang, Hao Wei, Qiannan Wang and Keren Zheng

Materials 2023, 16(2), 825; https://doi.org/10.3390/ma16020825 - 14 Jan 2023

Cited by 1 | Viewed by 1349

Abstract

Most reinforced concrete structures serve under windy environments, and the carbonation resistance under that circumstance exhibits significant difference from that under the steady (no wind) environment. In this study, a windy environment was simulated using one self-developed wind tunnel, and alkali-activated slag/fly ash [...] Read more.

Most reinforced concrete structures serve under windy environments, and the carbonation resistance under that circumstance exhibits significant difference from that under the steady (no wind) environment. In this study, a windy environment was simulated using one self-developed wind tunnel, and alkali-activated slag/fly ash paste specimens were adopted for the carbonation under variant windy environments. Meanwhile, to reveal the effect of inner humidity on the carbonation, sliced alkali-activated materials (AAM) were mass-balanced first to variant humidity, and were then carbonated under a 2.5 m/s windy environment. With the assistance of computed tomography (CT), the structure of AAM at variant carbonation ages was rendered. The experimental result showed that wind is capable of promoting the exchange of moisture between the sample inside and the outer atmosphere, leading to faster carbonation as compared to that under no wind environment. When preconditioned to lower inner humidity, the carbonation rate of AAM was faster because the larger gaseous space benefited the intrusion of both CO₂ and moisture. Furthermore, when preconditioned to lower humidity, the cracking extent of AAM was severer, which also contributed to the faster carbonation. Moreover, compared with ordinary Portland cement (OPC), the carbonation front on each instant 1D gray-scale value profile was broader, which suggested that the carbonation progress of AAM under windy environments was no longer controlled solely by diffusion. In addition, the gray-scale value on instant 1D profile fluctuated drastically, which verified cracking in AAM carbonated under windy environments. The current work not only deepens the understanding of the carbonation mechanism in-site (mostly under windy environments), but also helps to develop more environment-friendly construction material, with better durability performance. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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16 pages, 3769 KiB

Open AccessArticle

Effect of Alkali and Sulfate on the Hydration Characteristic of Cement-Based Materials Containing Coal Gasification Slag

by Zuzhong Li, Fan Li, Haiwei Xie, Weidong Liu, Rui He, Peiliang Cong and Jinhai Zeng

Materials 2022, 15(24), 8868; https://doi.org/10.3390/ma15248868 - 12 Dec 2022

Cited by 9 | Viewed by 2106

Abstract

Coal gasification slag is an inevitable by-product of the coal gasification process. This paper explored the feasibility of using activators (calcium hydroxide, sodium hydroxide, calcium sulfate, sodium sulfate) to promote the pozzolanic activity of milled coal gasification coarse slags (MCS), and analyzed the [...] Read more.

Coal gasification slag is an inevitable by-product of the coal gasification process. This paper explored the feasibility of using activators (calcium hydroxide, sodium hydroxide, calcium sulfate, sodium sulfate) to promote the pozzolanic activity of milled coal gasification coarse slags (MCS), and analyzed the effect of alkali and sulfate activators on the hydration characteristic of cement-based materials containing MCS. Coal gasification slags with ignition lossses more than 15% were removed and the remaining slags were considered as cementitious material after milling. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and hydration heat tests were employed to analyze the hydration mechanism of the samples. Besides, the compressive strength values of cement mortars with MCS and activators were evaluated. The results showed that calcium hydroxide was conductive to the formation of hydration products and its crystallization could contribute to the strength improvement of the sample. Calcium sulfate mainly participated in the hydration process of cement to form ettringite (AFt) phases. Sodium hydroxide could accelerate the dissolution of active mineral phases of MCS, resulting in the pozzolanic activity being enhanced. Moreover, sodium sulfate could not only increase the formation of AFt phases, but also improved the alkalinity in sample to facilitate the production of gels. Among them, a better promotion effect could be obtained from the combined application of calcium hydroxide and sodium sulfate. In addition, the compressive strength values of cement mortars containing MCS tended to increase when activators were used. The sample activated by calcium hydroxide and sodium sulfate exhibited the highest strength, increasing by 18.55% at 28 days compared with the sample without an activator. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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14 pages, 3808 KiB

Open AccessArticle

Evaluation of the Interfacial Interaction Ability between Basalt Fibers and the Asphalt Mastic

by Bangwei Wu, Zhaohui Pei, Peng Xiao and Keke Lou

Materials 2022, 15(22), 8209; https://doi.org/10.3390/ma15228209 - 18 Nov 2022

Cited by 2 | Viewed by 1379

Abstract

The interfacial properties between the asphalt mastic and fibers plays an essential role in the fiber-enhanced asphalt mixture properties. However, there is a lack of comprehensive studies on the indicators to evaluate the interfacial interaction ability of fibers with the asphalt mastic. Therefore, [...] Read more.

The interfacial properties between the asphalt mastic and fibers plays an essential role in the fiber-enhanced asphalt mixture properties. However, there is a lack of comprehensive studies on the indicators to evaluate the interfacial interaction ability of fibers with the asphalt mastic. Therefore, this paper selected three types of basalt fibers (denoted as A-BF, B-BF and C-BF) coated with different impregnating agents to prepare the fiber asphalt mastic. The Dynamic Shear Rheometer (DSR) test-based indicators, pull-out strength, and adhesion work were used to access the fiber asphalt mastic interfacial interaction ability. The differences between different indicators were compared and analyzed. The results show that all the selected indicators in this paper can effectively reflect the different fiber asphalt mastic interfacial properties. The evaluation results with different indicators are consistent. The interfacial interaction between fibers and the asphalt mastic increases with increasing temperature. The evaluation result with adhesion work is the most accurate. However, the pull-out strength test is simple, and the test result correlates well with adhesion work, which can be adopted daily to evaluate the fiber asphalt mastic interfacial properties. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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26 pages, 5327 KiB

Open AccessArticle

Integration of Rice Husk Ash as Supplementary Cementitious Material in the Production of Sustainable High-Strength Concrete

by Noor Md. Sadiqul Hasan, Md. Habibur Rahman Sobuz, Md. Munir Hayet Khan, Nusrat Jahan Mim, Md. Montaseer Meraz, Shuvo Dip Datta, Md. Jewel Rana, Ayan Saha, Abu Sayed Mohammad Akid, Md. Tanjid Mehedi, Moustafa Houda and Norsuzailina Mohamed Sutan

Materials 2022, 15(22), 8171; https://doi.org/10.3390/ma15228171 - 17 Nov 2022

Cited by 32 | Viewed by 4711

Abstract

The incorporation of waste materials generated in many industries has been actively advocated for in the construction industry, since they have the capacity to lessen the pollution on dumpsites, mitigate environmental resource consumption, and establish a sustainable environment. This research has been conducted [...] Read more.

The incorporation of waste materials generated in many industries has been actively advocated for in the construction industry, since they have the capacity to lessen the pollution on dumpsites, mitigate environmental resource consumption, and establish a sustainable environment. This research has been conducted to determine the influence of different rice husk ash (RHA) concentrations on the fresh and mechanical properties of high-strength concrete. RHA was employed to partially replace the cement at 5%, 10%, 15%, and 20% by weight. Fresh properties, such as slump, compacting factor, density, and surface absorption, were determined. In contrast, its mechanical properties, such as compressive strength, splitting tensile strength and flexural strength, were assessed after 7, 28, and 60 days. In addition, the microstructural evaluation, initial surface absorption test, = environmental impact, and cost–benefit analysis were evaluated. The results show that the incorporation of RHA reduces the workability of fresh mixes, while enhancing their compressive, splitting, and flexural strength up to 7.16%, 7.03%, and 3.82%, respectively. Moreover, incorporating 10% of RHA provides the highest compressive strength, splitting tensile, and flexural strength, with an improved initial surface absorption and microstructural evaluation and greater eco-strength efficiencies. Finally, a relatively lower CO₂-eq (equivalent to kg CO₂) per MPa for RHA concrete indicates the significant positive impact due to the reduced Global Warming Potential (GWP). Thus, the current findings demonstrated that RHA can be used in the concrete industry as a possible revenue source for developing sustainable concretes with high performance. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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17 pages, 4639 KiB

Open AccessArticle

Digital Twin Assistant Active Design and Optimization of Steel Mega-Sub Controlled Structural System under Severe Earthquake Waves

by Zheng Wei, Xun-An Zhang, Feng Sun and William Yi Wang

Materials 2022, 15(18), 6382; https://doi.org/10.3390/ma15186382 - 14 Sep 2022

Cited by 2 | Viewed by 1656

Abstract

In order to support the best optimized design or strategy based on life-cycle data, the interrelation mechanisms between structure–form and structure–performance should be considered simultaneously and comprehensively besides of the material–property relationship. Here, the structure–property–performance relationship of a designed steel mega-sub controlled structural [...] Read more.

In order to support the best optimized design or strategy based on life-cycle data, the interrelation mechanisms between structure–form and structure–performance should be considered simultaneously and comprehensively besides of the material–property relationship. Here, the structure–property–performance relationship of a designed steel mega-sub controlled structural system (MSCSS) under the reported earthquake waves has been investigated through integrating the finite element simulations and the experimental validations. It can be found that the MSCSS configurations are capable of effectively optimizing the vibration responses with significantly decreased acceleration, which is also much better than the traditional megaframe structure with extra weight. Moreover, if the horizontal connections between the sub- and the megastructures are broken, the displacement of the megastructure will be smaller than that of the substructure. This is because only the vertical connections between the sub- and megastructures work, the larger displacements or the obvious response of the substructures should be caused by the extra weight of the damper on the top floor. It is worth mentioning that the formation of abrupt amplified β of the top floors should be attributed to the sheath effect. Furthermore, the displacement of the substructure is one kind of energy dissipation. Its larger displacement will result in a greater amount of energy dissipation and better performance of the designed configuration. This work supports a digital twin assistant active design and optimization strategy to further improve the control effectiveness of the system and to enhance the mechanical performance of the optimized configuration of MSCSS. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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23 pages, 15259 KiB

Open AccessArticle

Relation between Microstructures and Macroscopic Mechanical Properties of Earthen-Site Soils

by Yingmin Zhang, Guang Yang, Wenwu Chen and Lizhi Sun

Materials 2022, 15(17), 6124; https://doi.org/10.3390/ma15176124 - 3 Sep 2022

Cited by 7 | Viewed by 1718

Abstract

While the macroscopic mechanical properties of earthen-site soils have undergone extensive experimental and modeling studies, few research efforts focus on the relationship between the overall mechanical behavior and micro-pore structure. We developed a microstructure-based finite element model to investigate the influence of micro-pore [...] Read more.

While the macroscopic mechanical properties of earthen-site soils have undergone extensive experimental and modeling studies, few research efforts focus on the relationship between the overall mechanical behavior and micro-pore structure. We developed a microstructure-based finite element model to investigate the influence of micro-pore structure on the macroscopic mechanical behavior of earthen-site soils. Scanning electron microscopy images of the untreated and consolidated soils were processed to compare the changes in equivalent diameter, sphericity, and porosity of the soils after consolidation. According to the pore parameter range of the untreated and consolidated soils, the effects of micro-pores on the soil behavior are specifically conducted under both static and dynamic loads. The relationships between pore characteristics and stiffness, strength, and ultrasonic wave velocity are established. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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17 pages, 5910 KiB

Open AccessArticle

A Universal Method for Modeling and Characterizing Non-Circular Packing Systems Based on n-Point Correlation Functions

by Shaobo Sun, Huisu Chen and Jianjun Lin

Materials 2022, 15(17), 5991; https://doi.org/10.3390/ma15175991 - 30 Aug 2022

Cited by 1 | Viewed by 1501

Abstract

A universal method for modeling and characterizing non-circular particles is developed. The n-point correlation functions (n = 1, 2 and 3) are efficiently computed with a GPU parallel computing procedure. An algorithm for dynamic packing of impenetrable non-circular particles is developed [...] Read more.

A universal method for modeling and characterizing non-circular particles is developed. The n-point correlation functions (n = 1, 2 and 3) are efficiently computed with a GPU parallel computing procedure. An algorithm for dynamic packing of impenetrable non-circular particles is developed based on the fast estimation of overlap information using a one-point correlation function. The packing algorithm is independent of particle shape and proved to be reliable by examples of polygons and super-ellipses. In addition, penetrable packings are generated in an efficient and precise way. Using a two-point correlation function, these non-circular packs are accurately characterized and compared in terms of features such as penetrable and impenetrable, packing fraction and particle shape. In addition, three-point correlation functions are also illustrated and discussed. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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12 pages, 6265 KiB

Open AccessArticle

Third-Order Effective Properties for Random-Packing Systems Using Statistical Micromechanics Based on a GPU Parallel Algorithm in Fast Computing n-Point Correlation Functions

by Shaobo Sun, Huisu Chen and Jianjun Lin

Materials 2022, 15(16), 5799; https://doi.org/10.3390/ma15165799 - 22 Aug 2022

Cited by 1 | Viewed by 1774

Abstract

Estimating the effective properties of a particulate system is the most direct way to understand its macroscopic performance. In this work, we accurately evaluate the third-order approximations involving the three-point microstructural parameter

ζ

, which can be calculated from a triple integral involving [...] Read more.

Estimating the effective properties of a particulate system is the most direct way to understand its macroscopic performance. In this work, we accurately evaluate the third-order approximations involving the three-point microstructural parameter

ζ

, which can be calculated from a triple integral involving 1-, 2-, and 3-point correlation functions. A GPU-based parallel algorithm was developed for quickly computing the n-point correlation functions, and the results agree well with analytical solutions. The effective thermal conductivity and diffusion coefficient are calculated by the third-order approximates for the random-packing systems of a super-ellipsoid. By changing the parameters of the super-ellipsoid, the particle-shape effect can be predicted for both the thermal conductivity and diffusion coefficient. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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15 pages, 5952 KiB

Open AccessArticle

Influence of Copper and Zinc Tailing Powder on the Hydration of Composite Cementitious Materials

by Weiwei Han, Fanghui Han and Ke Zhang

Materials 2022, 15(16), 5612; https://doi.org/10.3390/ma15165612 - 16 Aug 2022

Cited by 2 | Viewed by 1599

Abstract

Copper and zinc tailing powder (CZTP) is finely ground waste after copper minerals and zinc minerals have been extracted from ores during beneficiation. CZTP has certain potential cementitious properties and can be used in composite cementitious materials. The pore size distribution and hydrate [...] Read more.

Copper and zinc tailing powder (CZTP) is finely ground waste after copper minerals and zinc minerals have been extracted from ores during beneficiation. CZTP has certain potential cementitious properties and can be used in composite cementitious materials. The pore size distribution and hydrate phase assemblage of the hardened samples are investigated using MIP and XRD. SEM is employed to examine the microstructure of the specimens. The chemically bonded water is used to measure the degree of hydration. CZTP lowers the hydration heat evolution rate and the total hydration heat. The hydration heat evolution rate reduces as the w/b ratio rises, whereas the total hydration heat of blended cement paste rises. CZTP diminishes the strength development of the Portland-CZTP system, and the strength decreases as the CZTP level increases. CZTP reduces the critical pore diameters of the Portland-CZTP system with w/b = 0.3 after curing for 3 d and 28 d, while increasing the critical pore diameters of samples with w/b = 0.45 at the same age. CZTP increases the gel micropores of Portland-CZTP. Although CZTP increases the pore volume content of blended cement pastes with w/b = 0.3, the volume of harmful pores decreases. The pore volume content of the Portland-CZTP system decreases as the w/b ratio increases. However, the volume of harmful pores increases with a higher w/b ratio. The main hydration products in the Portland-CZTP system are portlandite, ettringite, and C-S-H. CZTP mainly played the role of filling or acting as a microaggregate in the Portland-CZTP system. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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14 pages, 4039 KiB

Open AccessArticle

Preparation of Organic-Inorganic Coupling Phase Change Materials with Enhanced Thermal Storage Performance via Emulsion Polymerization

by Xifeng Lv, Xuehua Shen, Luxiang Zhang, Yazhou Wang and Fang Wang

Materials 2022, 15(9), 3373; https://doi.org/10.3390/ma15093373 - 8 May 2022

Cited by 6 | Viewed by 1981

Abstract

The serious phase separation in inorganic phase change materials, and easy leakage of organic phase change materials are the main obstacles to the practical batch application of phase change heat storage materials. To solve these problems, in this work, emulsion polymerization is introduced [...] Read more.

The serious phase separation in inorganic phase change materials, and easy leakage of organic phase change materials are the main obstacles to the practical batch application of phase change heat storage materials. To solve these problems, in this work, emulsion polymerization is introduced as the method for preparing organic-inorganic coupling phase change material (oic-PCM) with high heat storage performance using polyacrylamide (PAM) as the wall material and organic phase change material of cetyl alcohol as the core material, and diatomite is used as a supporting substrate to absorb inorganic sodium sulfate decahydrate (SSD). A differential scanning calorimeter (DSC), X-ray diffractometer (XRD), dust morphology and dispersion analyzer, and thermal conductivity tester were used to characterize the prepared organic-inorganic coupled phase change materials and investigate their performance. The research results show that when the mass fraction of cetyl alcohol is 68.97%, the mass fraction of emulsifier is 3.38%, and the mass fraction of sodium sulfate decahydrate/diatomite is 3.40%. The phase change latent heat of the organic-inorganic coupled phase change material is as high as 164.13 J/g, and the thermal conductivity reaches up to 0.2061 W/(m·k), which proves that the prepared organic-inorganic coupled phase change material has good heat storage performance, showing its good application prospects. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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Open AccessReview

Wood Ash as Sustainable Alternative Raw Material for the Production of Concrete—A Review

by Ece Ezgi Teker Ercan, Lale Andreas, Andrzej Cwirzen and Karin Habermehl-Cwirzen

Materials 2023, 16(7), 2557; https://doi.org/10.3390/ma16072557 - 23 Mar 2023

Cited by 12 | Viewed by 4961

Abstract

Different ecological binders have been used to minimize the negative effects of cement production and use on the environment. Wood ash is one of these alternative binders, and there has been increasing research related to this topic recently. The wood ash utilized in [...] Read more.

Different ecological binders have been used to minimize the negative effects of cement production and use on the environment. Wood ash is one of these alternative binders, and there has been increasing research related to this topic recently. The wood ash utilized in the literature primarily originates from power plants and local bakeries, and predominantly wood fly ash is used. This review paper examines the use of wood ash as an ecological binder in two different applications: as a cement replacement and as an alkali-activated material. Studies have shown that while increased wood ash content in concrete and mortars can have negative effects on strength and durability, it is still a promising and developable material. Depending on the chemical composition of the wood ash, the strength and durability properties of concrete might be slightly improved by utilizing wood ash as a replacement for cement, with an optimal replacement level of 10–20%. However, there is a need for more research regarding the effects of wood ash on the durability of cement-based materials and its use in alkali-activated materials. Overall, this review provides a comprehensive overview of the properties of wood ash and its potential applications in conventional concrete and mortars, as well as in alkali-activated materials. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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