scholarly journals Evaluation of the Effect of Fly Ash and Slag on the Properties of Cement Asphalt Mortar

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Tri H. M. Le ◽  
Dae-Wook Park ◽  
Jin-Yong Park ◽  
Tam M. Phan
Keyword(s):  
Fly Ash ◽  
High Speed ◽  
Laboratory Experiments ◽  
Cost Effective ◽  
Hydration Product ◽  
Strength Development ◽  
Test Results ◽  
Cement Asphalt Mortar ◽  
Asphalt Mortar ◽  
By Products

The application of cement asphalt mortar (CAM) in modern high-speed railways has been gaining attention due to its combined merits between asphalt and cement hydration product characteristics. To promote sustainable development, it is promising to utilize by-products in the making of new CAM instead of using only cement. In this research, the cement content was partly replaced by fly ash or ground-granulated blast furnace (GGBS) slag to achieve this objective. Then, laboratory experiments were conducted to determine the effect of these admixtures on the fresh and hardened characteristics of CAM. The test results revealed that the CAM mixture with slag received better fresh properties compared to the controlled mixture. However, the poor pozzolanic property of these by-product materials may lead to the low strength development. Meanwhile, although the mixture with fly ash suffered from slow strength establishment compared to the control mix at an early age, the strength of this condition increases dramatically after 28 days. Based on the findings, the application of appropriate fly ash content in the CAM mixture will not only provide ideal workable time and mixing stability but also ensure the required strength for the design target. This combination also serves as a cost-effective and environmental solution.

scholarly journals Effect of Water and Emulsifier on the Mechanical Properties of Cement Asphalt Mortar

2019 ◽  
Vol 271 ◽  
pp. 03002
Author(s):  
Tri Ho Minh Le ◽  
Dae-Wook Park ◽  
Jung-Woo Seo
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Strength Development ◽  
Mechanical Degradation ◽  
Asphalt Emulsion ◽  
Term Operation ◽  
Cement Asphalt Mortar ◽  
Rail Structure ◽  
Asphalt Mortar ◽  
Mixing Water

The long-term operation of high-speed railway leads to remarkable issues in ballast mechanical degradation and track irregularity. Particularly, in mainline of rail structure, the required time for ballast layer maintenance is strictly short. To systematically cope with this problem, a comprehensive study was proposed to develop a new cement asphalt mortar (CAM) stabilized ballast method. This solution is expected to improve the ballast structural durability with fast application time. However, the engineer properties of CAM paste with different level of initial mixing water as well as the influencing mechanisms are not clearly understood. In this work, the effects of initial mixing water and emulsifier on the mechanical performance of CAM are mainly discussed. The characteristics of the mortar were determined by conducting the flowability test, mixing stability test, and unconfined compressive strength (UCS) test. The test results revealed that the initial mixing water plays an important role in both fresh and hardened stage of CAM, especially the demulsification process of asphalt emulsion. Meanwhile, the emulsifier imposed a critical effect on the strength development of CAM mixture.

scholarly journals A Step by Step Methodology for Building Sustainable Cementitious Matrices

2020 ◽  
Vol 10 (8) ◽  
pp. 2955 ◽  
Author(s):  
Styliani Papatzani ◽  
Kevin Paine
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
Carbon Footprint ◽  
State Of The Art ◽  
Cost Effective ◽  
Strength Development ◽  
Low Carbon ◽  
Current State ◽  
First Time

In an effort to produce cost-effective and environmentally friendly cementitious binders. mainly ternary (Portland cement + limestone + pozzolanas) formulations have been investigated so far. Various proportions of constituents have been suggested, all, however, employing typical Portland cement (PC) substitution rates, as prescribed by the current codes. With the current paper a step by step methodology on developing low carbon footprint binary, ternary and quaternary cementitious binders is presented (PC replacement up to 57%). Best performing binary (60% PC and 40% LS (limestone)) and ternary formulations (60% PC, 20% LS, 20% FA (fly ash) or 43% PC, 20% LS 37% FA) were selected on the grounds of sustainability and strength development and were further optimized with the addition of silica fume. For the first time a protocol for successfully selecting and testing binders was discussed and the combined effect of highly pozzolanic constituents in low PC content formulations was assessed and a number of successful matrices were recommended. The present paper enriched the current state of the art in composite low carbon footprint cementitious binders and can serve as a basis for further enhancements by other researchers in the field.

New Locking Arrangement for Radial Entry Turbine Blades

2011 ◽  
Author(s):  
Samuel L. Golinkin ◽  
Michael J. Lipski ◽  
John S. Loudon ◽  
Gennaro J. DiOrio ◽  
Timothy Ewer
Keyword(s):  
High Speed ◽  
Full Range ◽  
Turbine Blades ◽  
Cost Effective ◽  
Test Results ◽  
Cost Effective Method ◽  
Us Navy ◽  
Effective Design ◽  
Efficiency And Reliability ◽  
Bottom Portion

Turbine blades with radial fasteners (T-shank, radial fir-tree, etc.) are commonly used in current steam turbomachinery, especially in power generation applications. However, this reliable and cost-effective design is limited by the strength of the axial pins which lock the closing part in the radial entry slot in the disc. In applications with high speed rotors or heavy blades, the centrifugal force of the blade exceeds the pin strength. In those applications, the airfoil portion of the closing blade is cut off leaving only the bottom portion which is located in the radial entry slot. Some original equipment manufactures (OEMs) also remove the airfoil of the blade 180 degrees opposite for better balancing. The absence of two airfoils is detrimental to efficiency and reliability of the entire row. Siemens Demag Delaval Turbomachinery, Inc. (SDDTI) developed a new locking arrangement which eliminates the above described shortcoming associated with standard radial entry blades. This paper presents the design of the new patented locking arrangement and mechanical stress calculations (FEA) of its major components. In order to verify the validity of the design and calculations, a full-scale row of modernized radial entry blades for an existing US Navy turbine with the new locking arrangement was tested. The testing was done over the full range of operating speeds in a vacuum bunker. The paper also describes the special test rotor, instrumentation used, and the test results which were compared with the stress calculations. The tests confirmed all the advantages of the new locking arrangement and showed acceptable correlation with the stress calculations. The patented design will expand applications for radial entry blades, modernize radial entry blades with missing blade airfoils, and provide a cost-effective method to repair localized cracks in the fastener area of the turbine discs.

scholarly journals Dynamic Characteristics of Rubber Powder Modified Cement Asphalt Mortar

2012 ◽  
Vol 5 ◽  
pp. 243-246 ◽  
Author(s):  
Yun Liang Li ◽  
Yang Jian Ou ◽  
Yi Qiu Tan ◽  
Ming Yu Lu
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Beam Specimen ◽  
Rubber Powder ◽  
Cement Asphalt Mortar ◽  
Track System ◽  
Vibration Attenuation ◽  
Vibration Tests ◽  
The Impact ◽  
Asphalt Mortar

Cement asphalt mortar (CA) is mainly applied in track system of high-speed railways for vibration attenuation. The impact on dynamics performance of CA with the admixture of rubber powder was studied. The beam specimen made of CA was manufactured for analyzing its vibration frequency and damping characteristics by free attenuation vibration tests. Results showed that there was no big change for fundamental frequency after admixture of rubber powder. However, high order frequency and structural damping increased with the increase of admixture amount. Damping ratio of CA was increased by admixing rubber powder, which can be better for energy absorption and vibration attenuation.

scholarly journals STRENGTH DEVELOPMENT OF CONCRETE WITH FLY ASH ADDITION

2007 ◽  
Vol 13 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Marta Kosior-Kazberuk ◽  
Małgorzata Lelusz
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mathematical Models ◽  
Statistical Methods ◽  
Experimental Results ◽  
Strength Development ◽  
Hardened Concrete ◽  
Test Results ◽  
Different Types ◽  
Compressive Strength Of Concrete

Based on experimental results, mathematical models were elaborated to predict the development of compressive strength of concrete with fly ash replacement percentages up to 30 %. Strength of concrete with different types of cement (CEM I 42.5, CEM I 32.5, CEM III 32.5), after 2, 28, 90, 180 days of curing, have been analysed to evaluate the effect of addition content, the time of curing and the type of cement on the compressive strength changes. The adequacy of equations obtained was verified using statistical methods. The test results of selected properties of binders and hardened concrete with fly ash are also included. The analysis showed that concrete with fly ash is characterised by advantageous applicable qualities.

Effects of Change in Fineness of Fly Ash on Air-Entrained Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2195-2199 ◽  
Author(s):  
Hong Zhu Quan ◽  
Hideo Kasami
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Laboratory Experiments ◽  
Drying Shrinkage ◽  
Test Results ◽  
Air Entrained Concrete

In order to make clear of the effects of the change in fineness of fly ash on air-entrained concrete, 2 series of laboratory experiments were carried out using 6 kinds fly ash with the specific surface area in the range from 2500 to 4400cm2/g. The test results indicated higher slump and lower air-entraining content and higher dosage of air-entraining agent for fly ash with higher specific surface area. Compressive strength was found to increase with the increases of specific surface area of fly ash, while drying shrinkage and carbonation were found to show different tendency with change in fineness of fly ash.

scholarly journals Cement asphalt mortar for high-speed rail

2020 ◽  
Vol 65 (22) ◽  
pp. 2384-2394
Author(s):  
Dehua Deng ◽  
Qiang Yuan ◽  
Yong Wang
Keyword(s):  
High Speed ◽  
High Speed Rail ◽  
Cement Asphalt Mortar ◽  
Asphalt Mortar

Effect of Nano Silica and Ultrafine Fly Ash on Compressive Strength of High Volume Fly Ash Mortar

2013 ◽  
Vol 368-370 ◽  
pp. 1061-1065 ◽  
Author(s):  
Steve W.M. Supit ◽  
Faiz U.A. Shaikh ◽  
Prabir K. Sarker
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Partial Replacement ◽  
Strength Development ◽  
Test Results ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
High Volume Fly Ash ◽  
Class F Fly Ash

This paper evaluates the effect of Ultrafine Fly Ash (UFFA) and nanoSilica (NS) on compressive strength of high volume fly ash (HVFA) mortar at 7 days and 28 days. Three series of mortar mixes are considered in the first part of this study. In the first series the effect of high content of class F fly ash as partial replacement of cement at 40, 50 and 60% (by wt.) are considered. While in the second and third series, the UFFA and NS are used as partial replacement of cement at 5%, 8%, 10%, 12% and 15% and 1%, 2%, 4%, 6% and 8% (by wt.) of cement, respectively. The UFFA and the NS content which exhibited highest compressive strength in the above series are used in the second part where their effects on the compressive strength of HVFA mortars are evaluated. Results show that the mortar containing 10% UFFA as partial replacement of cement exhibited the highest compressive strength at both 7 and 28 days among all UFFA contents. Similarly, the mortar containing 2% NS as partial replacement of cement exhibited the best performance. Interestingly, the use of UFFA in HVFA mortars did not improve the compressive strength. However, the use of 2% and 4% NS showed improvement in the compressive strength of HVFA mortar containing 40% and 50% fly ash at both ages. The effects of NS and UFFA on the hydration and strength development of HVFA mortar is also evaluated through X-Ray Diffraction (XRD) test. Results also show that the UFFA and NS can significantly reduce the calcium hydroxide (CH) in HVFA mortars.

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