Mix Design for Flowable Fill

1997 ◽  
Vol 1589 (1) ◽  
pp. 26-28 ◽  
Author(s):  
S. T. Bhat ◽  
C. W. Lovell
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Ultimate Strength ◽  
Coal Combustion ◽  
Unconfined Compressive Strength ◽  
Mix Design ◽  
Target Strength ◽  
Fresh Material ◽  
Flowable Fill ◽  
Strength Material

The grout-like material called flowable fill has experienced new popularity, particularly the controlled low-strength material variety, which is easily excavated. The properties ordinarily desired of the mix are: (a) flow under gravity; (b) hardening for early walkability and cover; and (c) ultimate strength low enough to allow ready excavation. Flowability of fresh material is evaluated in a simple spread test. Hardening is measured by a mortar penetrometer, and these values are correlated with unconfined compressive strength. It is desirable to keep the ultimate strength to less than 1 035 kPa (150 lbf/in.2); somewhat less target strength is selected for the 28-day value. Mix design is empirical, but the time and expense required may be reduced by following a rational and logical procedure, which is described. The materials emphasized in this paper are Class F coal combustion fly ash and waste sands from greensand ferrous castings.

Phosphogypsum as a Component of Flowable Fill

1996 ◽  
Vol 1546 (1) ◽  
pp. 79-87
Author(s):  
S. Gandham ◽  
R. K. Seals ◽  
Paul T. Foxworthy
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Preliminary Test ◽  
Flowable Fill ◽  
Final Design ◽  
Potential Component ◽  
Class C ◽  
The Individual ◽  
Minimal Environmental Impact

Phosphogypsum (PG) is a by-product of the production of phosphoric acid, a key ingredient in the manufacture of fertilizers. Large amounts of PG have been stockpiled in Florida, Louisiana, and Texas, as well as other parts of the world. The means of using and disposing of this by-product with minimal environmental impact have been developed in research spanning almost 20 years. A study was conducted to investigate PG as a potential component of flowable fill materials along with Class C fly ash. Both Class F and Class C fly ashes have been used successfully to provide flowability and strength characteristics to flowable fill. A number of mix proportions of PG and fly ash were tested for flowability, time of setting, and unconfined compressive strength in a preliminary test series. Using the results of these preliminary tests, three final design mixtures were developed. These mixtures were then subjected to different physical and engineering property tests, including flowability, time of setting, unconfined compressive strength, flexural strength, dimensional stability, and permeability. Tests were also conducted to evaluate the environmental effects of the individual mixtures. These tests included the toxicity characteristic leaching procedure and radon emission testing. The results of this study indicated that PG can be used successfully as a component of flowable fill.

scholarly journals Characterization and Comparison Research on Composite of Alluvial Clayey Soil Modified with Fine Aggregates of Construction Waste and Fly Ash

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Construction Waste ◽  
Comparison Research ◽  
Fine Aggregates ◽  
Optimum Water Content

Abstract Fine aggregates of construction waste and fly ash were selected as additives to modify the characteristics of Shanghai clayey soil as a composite. The laboratory tests on consistency index, maximum dry density, and unconfined compressive strength were carried out mainly for the purpose of comparing the modifying effect on the composite from fine aggregates of construction waste with that from fly ash. It is mainly concluded from test results that the liquid and plastic limit of the composites increase with the content of two additives. But their maximum dry density all decreases with the additive content. However, fine aggregates of construction waste can increase the optimum water content of the composites, while fly ash on the contrary. Finally, although the two additive all can increase the unconfined compressive strength of composites, fly ash has better effect. The current conclusions are also compared with previous studies, which indicates that the current research results are not completely the same as those from other researchers.

The Latest Research in Mongolia on the Utilization of Coal Combustion By-Products

2021 ◽  
Vol 323 ◽  
pp. 8-13
Author(s):  
Jadambaa Temuujin ◽  
Damdinsuren Munkhtuvshin ◽  
Claus H. Ruescher
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Power Stations ◽  
Thermal Power Stations ◽  
Coal Ashes ◽  
By Products

With a geological reserve of over 170 billion tons, coal is the most abundant energy source in Mongolia with six operating thermal power stations. Moreover, in Ulaanbaatar city over 210000 families live in the Ger district and use over 800000 tons of coal as a fuel. The three thermal power plants in Ulaanbaatar burn about 5 million tons of coal, resulting in more than 500000 tons of coal combustion by-products per year. Globally, the ashes produced by thermal power plants, boilers, and single ovens pose serious environmental problems. The utilization of various types of waste is one of the factors determining the sustainability of cities. Therefore, the processing of wastes for re-use or disposal is a critical topic in waste management and materials research. According to research, the Mongolian capital city's air and soil quality has reached a disastrous level. The main reasons for air pollution in Ulaanbaatar are reported as being coal-fired stoves of the Ger residential district, thermal power stations, small and medium-sized low-pressure furnaces, and motor vehicles. Previously, coal ashes have been used to prepare advanced materials such as glass-ceramics with the hardness of 6.35 GPa, geopolymer concrete with compressive strength of over 30 MPa and zeolite A with a Cr (III) removal capacity of 35.8 mg/g. Here we discuss our latest results on the utilization of fly ash for preparation of a cement stabilized base layer for paved roads, mechanically activated fly ash for use in concrete production, and coal ash from the Ger district for preparation of an adsorbent. An addition of 20% fly ash to 5-8% cement made from a mixture of road base gave a compressive strength of ~ 4MPa, which exceeds the standard. Using coal ashes from Ger district prepared a new type of adsorbent material capable of removing various organic pollutants from tannery water was developed. This ash also showed weak leaching characteristics in water and acidic environment, which opens up an excellent opportunity to utilize.

Fly ash from Coal-Combustion Waste as an Additive for Quality Improvement and Compressive Strength of Cement

2021 ◽  
Vol 27 (1) ◽  
pp. 127-134
Author(s):  
Roni Adi Wijaya ◽  
Yayuk Astuti ◽  
Septi Wijayanti
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Combustion ◽  
National Standard ◽  
Insoluble Residue ◽  
Chemical Components ◽  
Free Lime ◽  
Mineral Additive ◽  
Additional Mineral

A series of tests were carried out to determine the effect of the addition of coal combustion fly ash as an additional mineral (additive) on improving the quality and compressive strength of cement according to the Indonesian National Standard (SNI 15-2049-2004). Research methods include sample preparation, manufacture of cement with 0%, 5%, 8%, 12%, and 15% fly ash variations, chemical and physical properties of cement. The parameters measured were the level of chemical composition (%) using X-Ray Fluorescence Spectroscopy (XRF) ARL 9800 OASIS, free lime content (%) by volumetry, insoluble residue level (%) by gravimetry, compressive strength (kg/cm2), and smoothness cement (cm2/g). The results showed that the addition of fly ash increased the SiO2 content of cement, thereby increasing C3S and C2S compounds which are compressive strength components of a cement. Besides, the addition of fly ash is directly proportional to IR levels, compressive strength, smoothness, and inversely proportional to free lime levels. So the addition of fly ash can improve the quality of cement by increasing chemical components, increasing compressive strength, and reducing cracking or expansion of cement.

STRENGTH OF CONCRETE MORTAR PREPARED BY PARTIAL SUBSTITUTION OF CEMENT WITH RECYCLED GLASS POWDER

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Pranshoo Solanki ◽  
Harsh Chauhan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Crucial Role ◽  
Glass Powder ◽  
Partial Substitution ◽  
Recycled Glass ◽  
Mortar Strength ◽  
Waste Glass Powder ◽  
Flowable Fill

This experiment was conducted to determine the utility of substituting cement with the recycled glass powder (RGP) in mortar mixtures. A total of 21 mortar mixtures were produced using various RGP (FG) ratios (CG), and fly ash (FA) powders. The mortar mixtures were used to prepare cubes which were tested for 7-and 28-day compressive strength. The substitution of cement with FG and CG in mortar resulted in reduced 7-and 28-day compressive strength values. However, the amount and type of RGP substituted for cement plays a crucial role in the determination of mortar strength. Above contraction in compressive strength was observed at an initial maturity than at the final maturity. Further, replacement of cement with Fly Ash showed increase in compressive strength up to certain content. More research and testing for the optimal percentage and size of waste glass powder that can be used is required in flowable fill.

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