Evaluation of Type C Fly Ash in Cold In-Place Recycling

1997 ◽  
Vol 1583 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Stephen A. Cross ◽  
David A. Young
Keyword(s):  
Fly Ash ◽  
Field Test ◽  
Fatigue Behavior ◽  
Hydrated Lime ◽  
Ash Content ◽  
Asphalt Emulsion ◽  
Moisture Sensitivity ◽  
Reclaimed Asphalt ◽  
Freeze Thaw ◽  
Type C

The Kansas Department of Transportation has developed an innovative method of rehabilitating low-volume pavements using cold in-place recycling (CIR) and Type C fly ash. Previous field test sections have indicated that fly ash improves constructability and moisture sensitivity. However, the same field test sections have exhibited increased cracking with increased fly ash content and a drop in pavement modulus with time. A laboratory study was undertaken to evaluate the effect of fly ash content on CIR. Reclaimed asphalt pavement (RAP) was mixed with 3, 7, 11, and 15 percent Type C fly ash and the fatigue life, durability, freeze-thaw resistance, and thermal cracking potential of laboratory-compacted samples were evaluated. RAP mixed with asphalt emulsion and asphalt emulsion with hydrated lime were evaluated as well. The results indicated that 7 to 11 percent Type C fly ash provided optimal laboratory freeze-thaw and moisture sensitivity performance. Increasing the fly ash content resulted in a brittle fatigue behavior as well as an increased thermal fracture temperature. AASHTO T283 is recommended for selecting the optimum fly ash content.

Estimating the Importance Degree of Influence Factors on Concrete Durability Based on Rough Set Theory

2014 ◽  
Vol 988 ◽  
pp. 191-194
Author(s):  
Xiao Ping Su ◽  
Hao Yue Sun
Keyword(s):  
Fly Ash ◽  
Set Theory ◽  
Rough Set ◽  
Loss Rate ◽  
Elasticity Modulus ◽  
Rough Set Theory ◽  
Ash Content ◽  
Concrete Durability ◽  
Freeze Thaw ◽  
Air Content

Under the saline soil environment in the western area of Jilin Province, the concrete durability is affected by a lot of factors, which include wet-dry cycles, freeze-thaw cycles, wet-dry and freeze-thaw cycles, salt soaking time, salts concentration, fly-ash content, air content. These factors impact on the durability of concrete is uncertain, and there may be a problem of duplicate action, with some roughness characteristics. In this article, the rough set theory is used to analyze the degree that these seven factors affect the concrete durability, and to calculate weights. In this article, the loss rate of dynamic elasticity modulus is looked as the evaluation index of concrete durability. The results show that: the importance degrees of 7 factors influencing the loss rate of concrete dynamic elasticity modulus in order are: wet-dry and freeze-thaw cycles > wet-dry cycle > freeze-thaw cycles > multiple salts concentration > air content > long-term soak > fly-ash content.

Study on the Freezing Resistance of HFCC

2011 ◽  
Vol 308-310 ◽  
pp. 2555-2559
Author(s):  
Hong Mei Ai ◽  
Pu Guang Lu ◽  
Jun Ying Bai ◽  
Jing Jing Wei
Keyword(s):  
Fly Ash ◽  
Compression Strength ◽  
Ash Content ◽  
Freezing Resistance ◽  
Cycle Times ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Binder Ratio ◽  
Water Binder Ratio

To the High fly-ash content concrete(abbreviated HFCC) whose fly-ash adding amount is 50%~70%, the influence of actual water-binder ratio, fly-ash content, quality of fly-ash and compression strength on the freezing resistance of HFCC were studied; The critical freeze-thaw cycle times in this paper involved with mass loss rate Wn=5% and relative dynamic elastic modulus P=60%, the relationship between the critical freeze-thaw cycle times and the 28d compression strength of HFCC was analyzed; To HFCC without air-entraining agent, the experiment results showed that the freezing resistance decreased with the increase of actual water-binder ratio, the increase of fly-ash content and the reduce of fly-ash quality. The freeze-thaw damage of HFCC dues to the freeze-thaw degradation results from surface denudation.

scholarly journals Improvement of the Salinized Soil Properties of Fly Ash by Freeze-Thaw Cycles: An Impact Test Study

2021 ◽  
Vol 13 (5) ◽  
pp. 2908
Author(s):  
Zhuo Cheng ◽  
Gaohang Cui ◽  
Zheng Yang ◽  
Haohang Gang ◽  
Zening Gao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Saline Soil ◽  
Friction Angle ◽  
Ash Content ◽  
Internal Friction Angle ◽  
Freeze Thaw ◽  
Salinized Soil

To explore the mechanism of the microstructural change in salinized soil under freeze-thaw cycles and the strength characteristics of subgrade salinized soil improved by fly ash, an unconfined compressive test, a triaxial shear test, and a scanning electron microscopy test were carried out using salinized soil samples with different fly ash contents along the Suihua to Daqing expressway in China. The results showed that after several freeze-thaw cycles, the unconfined compressive strength, triaxial shear strength, cohesion, and internal friction angle of saline soil showed a decreasing trend. With an increase in the fly ash content, the internal friction angle, cohesion, unconfined compressive strength, and shear strength of the improved saline soil first increased and then decreased. When the fly ash content was 15%, the mechanical indexes, such as cohesion and the internal friction angle, reached the maximum value. Microscopic test results showed that the freeze-thaw cycle will lead to an increase in the proportion of pores and cracks, an increase in the average pore size, and a loosening of the soil structure. The addition of fly ash can fill the soil pores, improve the microstructure of the soil, increase the cohesive force of the soil particles, and improve the overall strength of the soil. Fly ash (15%) can be added to subgrade soil in the process of subgrade construction in the Suihua-Daqing expressway area to improve the shear strength and the resistance to freezing and thawing cycles. These research results are conducive to promoting the comprehensive utilization of fly ash, improving the utilization rate of resources, and promoting sustainable development, thus providing a reference for the design and construction of saline soil roadbed engineering in seasonal frozen areas and the development and construction of saline land belts in seasonal and winter areas.

scholarly journals PHYSICAL AND MECHANICAL PROPERTIES RESEARCH AND ANALYSIS OF CONCRETE WITH BIOFUEL COMBUSTION FLY ASH SUPPLEMENT

2019 ◽  
Vol 11 (0) ◽  
pp. 1-5
Author(s):  
Deividas Augutis ◽  
Džigita Nagrockienė
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Physical And Mechanical Properties ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Ash Content ◽  
Closed Porosity ◽  
Freeze Thaw ◽  
Materials Used

Materials used for the study: Portland cement CEM I 42,5 R, 0/4 fraction sand, 4/16 fraction gravel, biofuel fly ash, superplastizer ViscoCrete D187 (V) and water. Seven compositions of concrete were designed by replacing 0%, 5%, 10%, 15%, 20%, 25% and 30% of cement with biofuel fly ash. The article analyses the effect of biofuel fly ash content on the properties of concrete. Studies have shown that the increase of biofuel fly ash content up to 15% increases concrete density and compressive strengh after 28 days of curing, compressive strength, ultrasonic pulse velocity, closed porosity, concrete forecasted freeze-thaw cycles and decreases water absorbtion, open porosity.

The fatigue behavior of polymeric sulfur-modified asphalt mixtures subjected to freeze-thaw conditioning

2019 ◽  
pp. 089270571988998 ◽  
Author(s):  
Amir Kavussi ◽  
Mehdi Azarnia ◽  
Pooyan Ayar ◽  
Makan Pedram
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Fatigue Cracking ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Experimental Results ◽  
Moisture Sensitivity ◽  
Modified Asphalt ◽  
Freeze Thaw ◽  
Brittle Behavior

Abundance, affordability, and also the usability of sulfur as a part of the binder are the main reasons for using this additive in asphalt mixtures. However, lack of proper adhesion and brittle behavior of sulfur-modified asphalt mixtures could make them susceptible to moisture damage and fatigue cracking. In this regard, anti-stripping agents and some polymers like crumb rubber may be used to overcome these types of distresses. This research aimed at investigating the effects of polymeric sulfur and crumb rubber on the moisture sensitivity and fatigue behavior of asphalt mixtures. To this end, asphalt mixtures were subjected to 1 and 3 freeze-thaw cycles. Then, an indirect tensile fatigue test was carried out. Moreover, the response surface method (RSM) was used to assess the interaction between various parameters in samples containing polymeric sulfur and crumb rubber. Results showed that with an increase in polymeric sulfur content, the fatigue life was reduced and the moisture sensitivity was increased. Additionally, the RSM was found to be effective in ranking parameters influencing the performance of asphalt mixtures. According to the experimental results, a crumb rubber-modified binder could improve the fatigue life of the polymeric sulfur-modified mixture up to 70%. Furthermore, experimental results and RSM analysis indicated that crumb rubber would be more effective in higher numbers of freeze-thaw cycles and raised temperatures, in which polymeric sulfur-modified asphalt mixtures are probably prone to moisture damages (i.e. the lack of adequate cohesion and adhesion).

scholarly journals Microstructural Features of Freezing and Thawing-Creep Damages for Concrete Mixed with Fly Ash

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bing Li ◽  
Lian-ying Zhang ◽  
Ming Li ◽  
Hai Pu ◽  
Chao Ma ◽  
...  
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Ash Content ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Ductile Fractures ◽  
Brittle Fractures ◽  
Morphology Characteristics ◽  
Fracture Features ◽  
Degree Of Fragmentation

The macroscopic morphology characteristics, pore structure characteristics, and microfracture morphology of concrete with fly ash subjected to the freeze-thaw-creep effect were analyzed via scanning electron microscopy (SEM). The results revealed that the macrosection of a specimen subjected to freeze-thaw cycling evolves from a regular to an irregular morphology in which the degree of fragmentation increases. Four specimen pore structure types characterized by single holes, nonconnected hole clusters, connected hole clusters, and fly ash holes, respectively, were identified. The microfracture morphology of the concrete was found to include five types of brittle fractures—river, step, cascade, hemispherical, and irregular patterns—and two types of ductile fractures—dimple and peak forest patterns. Two sets of experiments in which (1) the fly ash content ( m = 35 % ) was kept constant and the number of freeze-thaw cycles increased, and (2) the number of freeze-thaw cycles ( n = 120 ) was kept constant, and the fly ash content was increased were carried out. In both cases, the number of connected hole clusters increased and a surrounding skeleton structure with a needle filamentous or flaky appearance was produced. In addition, the degree of deterioration of the pore structure increased and the fracture features changed from brittle to ductile.

A Preliminary Study on Cracking Tendency of Cement Paste Incorporating High Calcium Fly Ash

2015 ◽  
Vol 815 ◽  
pp. 158-163
Author(s):  
Verryanto Goenawan ◽  
Antoni ◽  
Djwantoro Hardjito
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Ash Content ◽  
Factors Affecting ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Compressive Strength Test ◽  
Type C ◽  
Burning Coal

Fly ash is a waste material from burning coal that can be used to reduce the amount of cement in making concrete and to improve the characteristics of concrete. Besides being able to improve the flowability of fresh concrete, fly ash can also serve to reduce cracking of concrete. But in certain cases, cement paste incorporating fly ash type C (high calcium fly ash) experiences cracks, right after being released from formwork. The purpose of this study were to investigate the causes of cracking of cement paste incorporating fly ash type C, the influence of fly ash variations, and the countermeasures. The evaluation conducted for this experiment were based on visual inspection and compressive strength test of cement paste at 28 days. Test specimens were made in the form of cement paste with fly ash content of 50%, by mass. Fly ash used was of type C taken from three different batches from one source; with fly ash type F from three different sources used for control specimens. Superplasticizer, silica fume, and calcium carbonate were used as additives to evaluate their effect in mitigating cracks. The results show that the use of fly ash type C may cause cracks on the surface of hardened paste. Fly ash content, especially CaO and MgO, are the key factors affecting the cracks tendency on the surface of cement paste, due to expansion. Superplasticizer and silica fume can be used to mitigate cracks of cement paste.

scholarly journals Carbonization Law of Fly Ash Concrete under Freeze-Thaw Cycles Based on Image-Pro Plus

2020 ◽  
Vol 44 (6) ◽  
pp. 393-398
Author(s):  
Jing Yuan ◽  
Boxin Zhao ◽  
Zhenqiang Wang ◽  
Yan Liu
Keyword(s):  
Fly Ash ◽  
Linear Relationship ◽  
Concrete Structures ◽  
Ash Content ◽  
Experimental Results ◽  
Freeze Thaw ◽  
Fly Ash Concrete ◽  
Convergence Point ◽  
Research Findings

To understand the influence of freeze-thaw on the carbonization performance of concrete in severe cold areas, this paper conducted experiments to explore the carbonization law of fly ash concrete under freeze-thaw cycles. First, carbonization tests were conducted under different freeze-thaw cycles and fly ash contents; then PS (Photoshop) and IPP (Image-Pro Plus) were adopted to measure the carbonized area and calculate the ratio of carbonized area (RCA). The experimental results showed that, when the fly ash content was between 10% and 30%, RCA increased slowly; when the fly ash content was 20%, the convergence point showed up; when the fly ash content was 0, the air-entrained fly ash concrete had the best resistance to carbonation. With the help of PS and IPP, this paper calculated the RCA more accurately and found that, the freeze-thaw cycles can aggravate carbonization, and there is a linear relationship between carbonization depth and RCA. The research findings in this paper can provide a reference for the durability evaluation and design of concrete structures in severe cold areas.

Experimental Research on Chloride Ingress into Concrete Exposed to Freeze-Thaw Cycles

2013 ◽  
Vol 357-360 ◽  
pp. 621-625
Author(s):  
Si Jia Chen ◽  
Xiao Bing Song ◽  
Xi La Liu
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Experimental Research ◽  
Salt Solution ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Ash Content ◽  
Experimental Results ◽  
Chloride Ingress ◽  
Freeze Thaw

The most important mechanism of deterioration occurring in concrete in the cold regions are chloride ingress and freeze-thaw cycles. In this paper, the process of chloride ingress into concrete exposed to freeze-thaw cycles is experimentally researched. From the experimental results, it appears that freeze-thaw cycles make the effective diffusion coefficient become bigger. As w/c ratio increasing and fly ash content decreasing, the effective diffusion coefficient increases. The concentration of salt solution has little influence on the effective diffusion coefficient of concrete.

scholarly journals Influence of Asphalt Emulsion Inclusion on Fly Ash/Hydrated Lime Alkali-Activated Material

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7017
Author(s):  
Thanon Bualuang ◽  
Peerapong Jitsangiam ◽  
Teewara Suwan ◽  
Ubolluk Rattanasak ◽  
Weerachart Tangchirapat ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Material ◽  
Hydrated Lime ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Asphalt Emulsion ◽  
Structural Formation ◽  
Road Base ◽  
Alkali Activated ◽  
Road Bases

Supplementary cementitious materials have been widely used to reduce the greenhouse gas emissions caused by ordinary Portland cement (OPC), including in the construction of road bases. In addition, the use of OPC in road base stabilization is inefficient due to its moisture sensitivity and lack of flexibility. Therefore, this study investigates the effect of hybrid alkali-activated materials (H-AAM) on flexibility and water prevention when used as binders while proposing a new and sustainable material. A cationic asphalt emulsion (CAE) was applied to increase this cementless material’s resistance to moisture damage and flexibility. The physical properties and structural formation of this H-AAM, consisting of fly ash, hydrated lime, and sodium hydroxide, were examined. The results revealed that the addition of CAE decreased the material’s mechanical strength due to its hindrance of pozzolanic reactions and alkali activations. This study revealed decreases in the cementitious product’s peak in the x-ray diffraction analysis (XRD) tests and the number of tetrahedrons detected in the Fourier transform infrared spectroscopy analysis (FTIR) tests. The scanning electron microscope (SEM) images showed some signs of asphalt films surrounding hybrid alkali-activated particles and even some unreacted FA particles, indicating incomplete chemical reactions in the study material’s matrix. However, the H-AAM was still able to meet the minimum road base strength requirement of 1.72 MPa. Furthermore, the toughness and flexibility of the H-AAM were enhanced by CAE. Notably, adding 10% and 20% CAE by weight to the hybrid alkali-activated binder produced a significant advantage in terms of water absorption, which can be explained by its influence on the material’s consolidation of its matrices, resulting in significant void reductions. Hence, the outcomes of this study might reveal an opportunity for developing a new stabilizing agent for road bases with water-prevention properties and flexibility that remains faithful to the green construction material concept.

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