As the main component of concrete, aggregate has a significant impact on the performance of concrete. The aggregate is divided into natural aggregate and artificial aggregate according to its source, among which the a...As the main component of concrete, aggregate has a significant impact on the performance of concrete. The aggregate is divided into natural aggregate and artificial aggregate according to its source, among which the artificial aggregate is the concrete aggregate obtained by crushing, grinding and screening the rock mined by blasting. The soundness of aggregate is related to the joints of the original rock, the development degree of joints, the porosity, pore distribution, pore structure and water absorption capacity of the original rock. As an important index in concrete aggregate, soundness is an important factor affecting the strength and durability of concrete. When the soundness exceeds the specification index requirements, it is very necessary to study its impact on the strength and durability of concrete. Based on engineering examples, this paper mainly analyzes the influence of different degrees of soundness of aggregate on the performance of concrete, in order to provide some reference for other similar projects.展开更多
This study proposes the use of three-dimensional (3D) printed artificial aggregates as phase change material (PCM) carriers and investigates its effects on alkali-activated slag concrete. The artificial aggregates wer...This study proposes the use of three-dimensional (3D) printed artificial aggregates as phase change material (PCM) carriers and investigates its effects on alkali-activated slag concrete. The artificial aggregates were manufactured using Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques and PCM was injected into the artificial aggregates. Natural aggregates were replaced with FDM or SLA-type artificial aggregates by 15% and 30% by volume and alkali activated slag concrete specimens were produced. The characteristics of artificial aggregates and their impact on mechanical, physical, and thermal properties of concretes are examined. The results showed that 3D-printed artificial aggregates ameliorated the abrasion resistance of concrete specimens. The concrete samples had a minimum strength of 32 MPa after 28 d, with 15SLA concrete achieving 42.5 MPa, which is comparable to the reference concrete. Thermal test results demonstrated that the PCM helps maintain the concrete surface temperature 3.7 °C higher than the reference mix when the ambient temperature drops below zero and notably slows down the temperature decrease. The concrete mixes without PCM showed ice formation on their surfaces when the ambient temperature dropped to −5 °C, while no ice formation was observed on samples incorporating PCM. Furthermore, the inclusion of PCM improved the freeze–thaw resistance of concretes.展开更多
Wet granulation is a potential method to develop artificial aggregates.In this paper,the granulation of recycled alkali-activated slag powders with different particle size(d_(50) ranging between 12.9-127.7μm)distribu...Wet granulation is a potential method to develop artificial aggregates.In this paper,the granulation of recycled alkali-activated slag powders with different particle size(d_(50) ranging between 12.9-127.7μm)distributions were investigated in order to find how these affect on the engineering properties of the artificial aggregates.Blast furnace slag was added as co-binder in 10-30 wt.%during the granulation process and to enhance the properties,especially mechanical strength.The results show that the particle size of the raw material significantly affects the engineering properties of the produced aggregates,such as the crushing force(19-131.8 N),bulk density,water absorption,porosity and microstructure of the granules.The results show that granulation is a promising method to recycle alkali-activated materials as lightweight aggregates to replace natural aggregates.展开更多
文摘As the main component of concrete, aggregate has a significant impact on the performance of concrete. The aggregate is divided into natural aggregate and artificial aggregate according to its source, among which the artificial aggregate is the concrete aggregate obtained by crushing, grinding and screening the rock mined by blasting. The soundness of aggregate is related to the joints of the original rock, the development degree of joints, the porosity, pore distribution, pore structure and water absorption capacity of the original rock. As an important index in concrete aggregate, soundness is an important factor affecting the strength and durability of concrete. When the soundness exceeds the specification index requirements, it is very necessary to study its impact on the strength and durability of concrete. Based on engineering examples, this paper mainly analyzes the influence of different degrees of soundness of aggregate on the performance of concrete, in order to provide some reference for other similar projects.
基金supported by Yildiz Technical University Scientific Research Projects Coordination Unit under project number FDK-2022-4808.
文摘This study proposes the use of three-dimensional (3D) printed artificial aggregates as phase change material (PCM) carriers and investigates its effects on alkali-activated slag concrete. The artificial aggregates were manufactured using Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques and PCM was injected into the artificial aggregates. Natural aggregates were replaced with FDM or SLA-type artificial aggregates by 15% and 30% by volume and alkali activated slag concrete specimens were produced. The characteristics of artificial aggregates and their impact on mechanical, physical, and thermal properties of concretes are examined. The results showed that 3D-printed artificial aggregates ameliorated the abrasion resistance of concrete specimens. The concrete samples had a minimum strength of 32 MPa after 28 d, with 15SLA concrete achieving 42.5 MPa, which is comparable to the reference concrete. Thermal test results demonstrated that the PCM helps maintain the concrete surface temperature 3.7 °C higher than the reference mix when the ambient temperature drops below zero and notably slows down the temperature decrease. The concrete mixes without PCM showed ice formation on their surfaces when the ambient temperature dropped to −5 °C, while no ice formation was observed on samples incorporating PCM. Furthermore, the inclusion of PCM improved the freeze–thaw resistance of concretes.
基金support received for the project DeConcrete Eco-Efficient Arctic technologies cooperation funded by kolarctic CBC initiative of European Union(KO 4068).XRD analysis was performed at the Center of Microscopy and Nanotechnology(University of Oulu).The authors would like to thank Jarno Karvonen and Elisa Wirkkala for their assistance with the laboratory experiments.
文摘Wet granulation is a potential method to develop artificial aggregates.In this paper,the granulation of recycled alkali-activated slag powders with different particle size(d_(50) ranging between 12.9-127.7μm)distributions were investigated in order to find how these affect on the engineering properties of the artificial aggregates.Blast furnace slag was added as co-binder in 10-30 wt.%during the granulation process and to enhance the properties,especially mechanical strength.The results show that the particle size of the raw material significantly affects the engineering properties of the produced aggregates,such as the crushing force(19-131.8 N),bulk density,water absorption,porosity and microstructure of the granules.The results show that granulation is a promising method to recycle alkali-activated materials as lightweight aggregates to replace natural aggregates.
