scholarly journals Study on Road Performance of Cement Fly Ash Stabilized Steel Slag—Concrete Recycled Macadam

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7530
Author(s):  
Hongbo Li ◽  
Yufei Tong ◽  
Hubiao Zhang ◽  
Xuanshuo Zhang ◽  
Junku Duan
Keyword(s):  
Steel Slag ◽  
Base Material ◽  
Microscopic Analysis ◽  
Drying Shrinkage ◽  
Scientific Basis ◽  
Utilization Rate ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Suitable Amount ◽  
Slag Content

In order to promote the application of steel slag in road engineering, improve its utilization rate and solve the environmental problems caused by its large accumulation, unconfined compressive strength (UCS) test, indirect tensile strength (ITS) test, freeze-thaw cycle test, dry shrinkage and temperature shrinkage test tests with different steel slag contents were carried out. And the strength formation mechanism of steel slag in base material was revealed by SEM. The results show that the strength of the mixture initially increased and then decreased with increasing steel slag content. The frost resistance increased with increasing steel slag content, which should be limited to no more than 75%. Increasing the steel slag content improved the drying shrinkage resistance but was not conducive to the temperature shrinkage resistance. Microscopic analysis shows that adding a suitable amount of steel slag generated a gel material that was distributed inside the pores. This increased the density of the hardened slurry structure, which improved the strength. The research can provide scientific basis for the application and promotion of steel slag in road base.

Effect of Steel Slag on Shrinkage Characteristics of Calcium Sulfoaluminate Cement

2021 ◽  
Vol 1036 ◽  
pp. 263-276
Author(s):  
Hao Ran Huang ◽  
Yi Shun Liao ◽  
Siraj Ai Qunaynah ◽  
Guo Xi Jiang ◽  
Da Wei Guo ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Relative Humidity ◽  
Cement Paste ◽  
Steel Slag ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Slag Content

The effects of steel slag with 0, 10%, 20 % and 40% content on the chemical shrinkage, autogenous shrinkage, internal relative humidity, and drying shrinkage of calcium sulfoaluminate cement paste were studied. The results show that the compressive strength of calcium sulfoaluminate cement paste at an early stage decreases gradually when the content of steel slag increases. When the steel slag content is 0 and 10%, the compressive strength of hardened cement pastes gradually decreases at 90 and 180 days, but the samples with steel slag content of 20% and 40% maintain the compressive strength growth within 180 d. With the extension of curing period, the gap of compressive strength is gradually narrowed. The autogenous shrinkage decreases with the increase of steel slag content and has a good linear relationship with the relative humidity inside the paste. The proportion of autogenous shrinkage to chemical shrinkage is deficient, and most chemical shrinkage occurs in the form of the pore volume. Although the trends of drying shrinkage and autogenous are consistent, the former is more severe than the latter.

Preparation and Properties of Concrete Containing Iron Tailings/Manufactured Sand as Fine Aggregate

2013 ◽  
Vol 838-841 ◽  
pp. 152-155 ◽  
Author(s):  
Guo Dong Zhang ◽  
Xiu Zhi Zhang ◽  
Zong Hui Zhou ◽  
Xin Cheng
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Drying Shrinkage ◽  
Strength Loss ◽  
Fine Aggregate ◽  
River Sand ◽  
Manufactured Sand ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

High performance concrete was prepared by using iron tailings mixed with manufactured sand. Effects of the content of iron tailings on the performance of concrete were studied. The results show that the slump of concrete containing iron tailings is equal to concrete with river sand when the content of iron tailings is 60%. With the increase of the content of iron tailings, compressive strength of concrete shows a trend of decrease at same age; meanwhile drying shrinkage decreases and is less than the concrete prepared river sand. After 200 times of freeze-thaw cycle, mass loss of concrete with mixed sand is less than 5% and compressive strength loss is less than 25% which are close to concrete with river sand.

Experimental Study on Steel Slag-Limestone Powder Concrete after Freezing and Thawing Cycles

2014 ◽  
Vol 1065-1069 ◽  
pp. 1862-1866
Author(s):  
Ming Zhen Han ◽  
Zhi Yun Zhou ◽  
Fei Yang ◽  
Ya Wei Zhan
Keyword(s):  
Loss Modulus ◽  
Damage Model ◽  
Steel Slag ◽  
Test Method ◽  
Limestone Powder ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Freezing And Thawing Cycles

Using the fast freeze-thaw test method, we tested the loss modulus and compressive strength of steel slag-limestone powder concrete after 0,25 times,50 times,75 times,100 times freeze-thaw cycle,studied the mechanical properties and frost resistance performance after the freeze-thaw cycle. The results showed that adding a certain amount of steel slag-limestone powder does not affect the anti-frost property of concrete; established different dosage of steel slag concrete freeze-thaw damage model: y = a + bx + cx2, degree of fitting is better; large quantity of steel slag used in concrete shall be a wider range of research.

scholarly journals Sustainable Development of Chitosan/Calotropis procera-Based Hydrogels to Stimulate Formation of Granulation Tissue and Angiogenesis in Wound Healing Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3284
Author(s):  
Muhammad Zahid ◽  
Maria Lodhi ◽  
Zulfiqar Ahmad Rehan ◽  
Hamna Tayyab ◽  
Talha Javed ◽  
...  
Keyword(s):  
Wound Healing ◽  
Blood Vessels ◽  
Granulation Tissue ◽  
Chorioallantoic Membrane ◽  
Calotropis Procera ◽  
Connective Tissues ◽  
Blood Capillaries ◽  
Chick Chorioallantoic Membrane ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

The formation of new scaffolds to enhance healing magnitude is necessarily required in biomedical applications. Granulation tissue formation is a crucial stage of wound healing in which granulation tissue grows on the surface of a wound by the formation of connective tissue and blood vessels. In the present study, porous hydrogels were synthesized using chitosan incorporating latex of the Calotropis procera plant by using a freeze–thaw cycle to stimulate the formation of granulation tissue and angiogenesis in wound healing applications. Structural analysis through Fourier transform infrared (FTIR) spectroscopy confirmed the interaction between chitosan and Calotropis procera. Latex extract containing hydrogel showed slightly higher absorption than the control during water absorption analysis. Thermogravimetric analysis showed high thermal stability of the 60:40 combination of chitosan (CS) and Calotropis procera as compared to all other treatments and controls. A fabricated scaffold application on a chick chorioallantoic membrane (CAM) showed that all hydrogels containing latex extract resulted in a significant formation of blood vessels and regeneration of cells. Overall, the formation of connective tissues and blood capillaries and healing magnitude decreased in ascending order of concentration of extract.

scholarly journals Effect of freeze–thaw cycle on physical and mechanical properties and damage characteristics of sandstone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Longxiao Chen ◽  
Kesheng Li ◽  
Guilei Song ◽  
Deng Zhang ◽  
Chuanxiao Liu
Keyword(s):  
Mechanical Properties ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Physical And Mechanical Properties ◽  
Freeze Thaw ◽  
Damage Characteristics ◽  
Large Pore ◽  
Natural Rock ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

AbstractRock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.

Non-linear creep damage model of sandstone under freeze-thaw cycle

2021 ◽  
Vol 28 (3) ◽  
pp. 954-967
Author(s):  
Jie-lin Li ◽  
Long-yin Zhu ◽  
Ke-ping Zhou ◽  
Hui Chen ◽  
Le Gao ◽  
...  
Keyword(s):  
Damage Model ◽  
Creep Damage ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Linear Creep ◽  
Non Linear ◽  
Freeze Thaw Cycle ◽  
Creep Damage Model

scholarly journals Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huren Rong ◽  
Jingyu Gu ◽  
Miren Rong ◽  
Hong Liu ◽  
Jiayao Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Power Function ◽  
Damage Mechanism ◽  
Uniaxial Compression Test ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

Studies the Properties of Polyaspartic Polyurea Coated Concrete under Coaction of Salt Fog and Freeze-Thaw

2012 ◽  
Vol 455-456 ◽  
pp. 781-785
Author(s):  
Ping Lu ◽  
Xin Mao Li ◽  
Xue Qiang Ma ◽  
Wei Bo Huang
Keyword(s):  
Elastic Modulus ◽  
Frost Resistance ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw ◽  
Decrease Rate ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Salt Fog

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.

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