Evaluating the Use of Ponded Fly Ash in a Roadway Base Course

1989 ◽  
Vol 178 ◽  
Author(s):  
David Q. Hunsucker ◽  
R. Clark Graves

AbstractThis paper summarizes findings of laboratory and field trial evaluations of ponded fly ash used as a component in a stabilized aggregate base course. Ponded fly ash is the fine portion of pond ash which is a by-product of a coal burning process and is disposed by sluicing to a disposal pond.Three stabilized aggregate base mixtures containing various proportions of dense graded aggregate, ponded fly ash, and hydrated lime were evaluated in the laboratory relative to maximum dry density, optimum moisture content, unconfined compressive strength, and static chord modulus of elasticity. The mixture that was selected for field trial evaluation had the highest unconfined compressive strength and consisted of 84% dense graded aggregate, 11% ponded fly ash, and 5% hydrated lime.A 750 foot section of a 22 foot wide roadway was constructed in May 1988. Approximately 88 tons of ponded fly ash were utilized in constructing the experimental base. Prior to construction, in-place California Bearing Ratio tests, moisture content determinations and Road Rater deflection tests were performed on the prepared subgrade. The stabilized aggregate base was placed in one 8 inch lift. During construction, relative compaction and moisture content of the base material were monitored by means of nuclear devices. Post construction evaluations included Road Rater deflection tests and coring to obtain samples for laboratory evaluation.To date, the section containing the stabilized aggregate base is performing very well in comparison to the conventionally paved section.

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao

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.


2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Anigilaje B Salahudeen ◽  
Ja’afar A Sadeeq

The study investigate the suitability of subgrade soil in Baure Local Government Area of Kastina State Nigeria for road construction. The strength properties of the  subgrade was improved using lime and cement. Several analysis including the particle size distribution, specific gravity, Atterberg limits, compaction characteristics, unconfined compressive strength and California bearing ratio tests were performed on natural and lime/cement treated soil samples in accordance with BS 1377 (1990) and BS 1924 (1990) respectively. Soil specimens were prepared by mixing the soil with lime and cement in steps of 0, 3, 6, and 9% by weight of dry soil in several percentage combinations. The Atterberg limits of the weak subgrade soils improved having a minimum plasticity index value of 5.70 % at 3%Lime/6%Cement contents. The maximum dry density (MDD) values obtained showed a significant improvement having a peak value of 1.66 kN/m3 at 9%Lime/9%Cement contents. Similarly, a minimum value of 18.50 % was observed for optimum moisture content at 9%Lime/9%Cement contents which is a desirable reduction from a value of 25.00 % for the natural soil. The unconfined compressive test value increased from 167.30 kN/m2 for the natural soil to 446.77 kN/m2 at 9%Lime/9%Cement contents 28 days curing period. Likewise, the soaked California bearing ratio values increased from 2.90 % for the natural soil to 83.90 % at 9%Lime/9%Cement contents. Generally, there were improvements in the engineering properties of the weak subgrade soil when treated with lime and cement. However, the peak UCS value of 446.77 kN/m2 fails to meet the recommended UCS value of 1710 KN/m2 specified by TRRL (1977) as a criterion for adequate stabilization using Ordinary Portland Cement.            Keywords: Weak subgrade soil, Lime, Cement, Atterberg limits, Maximum dry density, Optimum moisture content, Unconfined compressive strength, California bearing ratio


1987 ◽  
Vol 113 ◽  
Author(s):  
Petros Zenieris ◽  
Joakim G. Laguros

ABSTRACTThe benefit of adding up to 35 wt% Class C high calcium fly ash to various types of fine and coarse aggregate pavement mixes is described and quantified. The mixes, which were compacted to maximum dry density at optimum moisture content, had variable compressive strengths during the first 28 days of curing; after that they assumed a relatively uniform pattern of strength gain reaching values as high as 11 MPa (1600 psi). Mixes containing 15% fly ash gave unacceptably low strengths. XRD measurements indicated massive formation of ettringite, transforming to monosulfoaluminate and the poorly crystallized hydrated phases of C-A-H, C-A-S-H and C-S-H. This transformation helps explain the gain in strength of the mixes with extended curing. SEM observations depicted progressive packing and densification of the skeletal matrix as the hexagonal phases and C-S-H gained higher crystallinity and formed aggregated masses. Furthermore, these observations suggest that fly ash acts predominantly as a chemical binder and partly as a filler in the aggregate mixes tested.


2014 ◽  
Vol 507 ◽  
pp. 353-360 ◽  
Author(s):  
Amiruddin Ismail ◽  
Mojtaba Shojaei Baghini ◽  
Mohamed Rehan Karim ◽  
Foad Shokri ◽  
Ramez A. Al-Mansob ◽  
...  

Cement-Treated Base (CTB) is a non-conventional method used in road bases materials to improve its engineering properties due to the hardening of cement when moisture is present and extends the period of curing times. This study investigates the effects of cement additive on properties of base layer using laboratory mechanistic evaluation of stabilized soil mixtures. Laboratory tests conducted were Unconfined Compressive Strength (UCS), Indirect Tension test for Resilient Modulus (ITRM) and Flexure Strength (FS) tests. The results revealed that by adding Portland cement, the mechanical properties of the mixture have improved where the UCS is found to be an important quality indicator. In addition, the variables that influenced these tests, which are cement content, curing time, moisture content, and dry density, play important role to determine the performance of CTB. This paper presents the finding of a correlation conducted to analyse the influences of these variables using regression and ANOVA to establish significant models with the aim of predicting the strength base on mixture parameters. Keywords: Cement-Treated Base, Unconfined Compressive Strength, Indirect Tension test for Resilient Modulus, Flexure Strength, Moisture Content, Dry Density, Regression Analysis.


CivilEng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 1009-1018
Author(s):  
Salar Shirkhanloo ◽  
Mohammad Najafi ◽  
Vinayak Kaushal ◽  
Mehrdad Rajabi

Clays generally have a low strength and capacity, and additives are usually used to stabilize them. In recent years, using fly ash to stabilize soil has decreased environmental pollution while also having an economic benefit. The objective of this study is to perform a comparative investigation on the effect of class C and class F fly ashes on geotechnical properties of high-plasticity clay using the Atterberg’s limit, compaction, California Bearing Ratio (CBR), and unconfined compressive strength tests. The results showed that with an increase in the amount of fly ash, there was a decrease in the maximum dry density and an increase in the optimum moisture content. Moreover, an addition of fly ashes of up to 25% caused a reduction of the liquid limit and plasticity index, and an increase in the maximum unconfined compressive strength and CBR. Lengthening the curing time had a positive impact on the unconfined compressive strength of the soil. The soil samples with class C fly ash were seen to possess more efficient geotechnical properties as compared to class F fly ash.


2014 ◽  
Vol 695 ◽  
pp. 738-741
Author(s):  
Azhani Zukri ◽  
Nadiatul Adilah Ahmad Abdul Ghani

This study involves the clay sample which is taken from Kampung Kedaik Asal, Rompin site and evaluation of its properties in natural state and after stabilization. The main objectives of this paper is to estimate the optimum lime content (OLC) needed to stabilize the soil by using Eades-Grim pH Test, to determine the optimum moisture content (OMC) and maximum dry density (MDD) of the treated soil by Standard Proctor Test and also the strength value of the soil specimens with different percentages of lime content corresponding with different curing period by Unconfined Compressive Strength (UCS) Test. From this study, the optimum amount to stabilize the clay soil and minimum amount of lime required to stabilize the soil pH level to 12 is 5%. The results showed that addition of lime decreased the maximum dry density (MDD) and increased the optimum moisture content (OMC). Unconfined compressive test on 48 sets of samples has been carried out for 7, 14 and 28 days of curing with different lime contents such as 5%, 7% and 9%. The highest unconfined compressive strength (UCS) achieved is 321 kN/m2 for clay stabilized with 9% lime content cured at 28 days. From the test results, it was found that the longer the immersion of curing period with higher lime content, the greater the compressive strength of the specimen.


Author(s):  
Phoolwanti Nanda

Abstract: The usage of waste material for stabilizing black cotton soil has been a sustainable interest. Kota stone slurry is a waste from kota stone and fly ash is a waste from industries containing high amount of sodium and magnesium, was used as a soil stabilizer for blac cotton soil improvement in this study. This research investigated the effects of sizes and percentages of kota stone slurry mix and fly ash on the physical and strength properties, which included particle size distribution, Atterberg limits, compaction, and unconfined compressive strength (UCS) of blac cotton soil. Micro structural characterization, including the scanning electron microscopic, energy dispersive X-ray spectroscopy, and X-ray diffraction was conducted on both untreated and treated black cotton soil samples to examine the mechanism of strength development. The addition of kota stone slurry and fly ash reduced the water holding capacity, which then caused the reduction in soil plasticity (from 18 to 11%) and optimum water content (from 20 to 16%) along with the increase in peak dry density (from 1.66 to 1.74 Mg/m3). The strength of black cotton soil may increased from 50 to almost 220 kPa. The optimum kota stone slurry and fly ash contents, providing the highest UCS, were at 20 and 30% for 0.063 mm kota stone slurry and fly ash and 0.15 mm kota stone slurry and fly ash, respectively. The UCS improvement of treated marine clay is attributed to the formation of cementation compounds, mainly aluminum magnesium silicate hydrate (A–M–S–H). The outcome of this research will allow the use of RBT as a low-carbon soil stabilizer across civil engineering applications. Keywords: Stablization, Fly ash, kota stone slurry, Atterberg limits, Compaction, and unconfined compressive strength


2010 ◽  
Vol 1 (2) ◽  
pp. 1-5 ◽  
Author(s):  
Kolay P.K. ◽  
Pui M.P.

This paper presents the stabilization of local peat soil from Matang, Sarawak, using gypsum and fly ash. Peat soil has been identified as one of the major groups of soils found in Malaysia, which has high compressibility and low shear strength. Presence of soft or peaty soil is a major problem encountered by civil engineers in Sarawak. Different percentages of gypsum (i.e., 2, 4, 6 and 8%) and fly ash (i.e., 5, 10, 15, 20 and 25%) were added into peat soil at optimum moisture content and it’s maximum dry density determined by standard Proctor test. Unconfined compressive strength (UCS) test were conducted to determine the strength gain after 7, 14 and 28 days of curing periods. Physical properties of the peat soil have also been studied for identification and classification purposes. The unconfined compressive strength test results show that the peat soil gained strength due to the addition of different percentages of admixtures such as gypsum and fly ash and the strength also increases with the increase of curing periods.


2020 ◽  
Vol 8 (2) ◽  
pp. 35
Author(s):  
Thompson Henry Tolulope Ogunribido ◽  
Tunde Ezekiel Fadairo

Twenty soil samples collected from the failed portions in the study area were air dried for two weeks before analyses. Each soil samples were subjected to eight engineering tests which include: natural moisture content, atterberg limit, specific gravity, compaction, unconfined compressive strength, California bearing ratio, grain size and hydrometer analysis. Results showed that the natural moisture content ranged from 17.7% to 37.8%, liquid limit from 48.5% to 62.4%, plastic limit from 18.3% to 26.8%, plasticity index from 25.7% to 37.7%, shrinkage limit from 5.8%-12.5%, optimum moisture content from 14.2% to 32.4%, maximum dry density from 1301 Kg/rn3 to 2002 Kg/rn3. Soaked California bearing ratio ranged from 5% to 17%, unsoaked from 15% to 38%, specific gravity from 2.5 to 2.68, unconfined compressive strength r from 112.8 Kpa to 259.7 Kpa, shear strength from 56.4 Kpa to 129.9 Kpa and hydrometer analysis from 48.5% to 72.1%. Based on the Federal Government specifications for pavement construction, for the soil to be suitable, stabilization with bitumen, Portland cement, lime, coal fly ash, and saw dust should be done. Road pavement failure along Arigidi – Oke Agbe road was due to poor engineering geological condition of the sub-grade soils and poor drainage systems.  


2021 ◽  
Vol 13 (1) ◽  
pp. 1523-1535
Author(s):  
Syed Husnain Ali Shah ◽  
Mohammad Arif ◽  
Qasim ur Rehman ◽  
Fawaz Manzoor

Abstract This study explores how dolerite cutting waste could be utilized for improving the quality of compacted clay soils. Different proportions of dolerite waste powder with varying grain sizes were used as admixtures and their impact on clay soil properties investigated. Ten samples were prepared by mixing clay soil with different proportions of dolerite waste powder having grain sizes of 0.210, 0.297, and 0.420 mm. The resulting samples were subjected to Proctor compaction, and their maximum dry density and optimum moisture content were measured. Next, all the compacted samples were subjected to geotechnical testing, including the determination of Atterberg limits, California bearing ratio (CBR), unconfined compressive strength, and specific gravity (Gs). The values of compaction parameters, Atterberg limits, and Gs were utilized for finding the porosity, void ratio, saturation potential, liquidity index (LI), and consistency index (CI). The results demonstrate that the addition of dolerite powder produces a substantial improvement in the plasticity index, compaction parameters, CBR, unconfined compressive strength, Gs, porosity, void ratio, degree of saturation, LI, and CI. The foremost reason for this improvement is the presence of denser and less water-adoring minerals in the added dolerite relative to pristine clay soil. Furthermore, the observed positive impact on the soils’ geotechnical comportment is comparatively higher with coarser than finer dolerite because of the decrease in surface area that causes a reduction in the moisture content and porosity but an increase in the density of soil.


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