Influence of Humic Acid on the Strength Behavior of Cement-Treated Clay during Various Curing Stages

Kang, Gyeong-o; Tsuchida, Takashi; Kim, Young Sang; Baek, Won-Jin

doi:10.1061/(asce)mt.1943-5533.0001919

Cited by 30 publications

(13 citation statements)

References 21 publications

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“…Confirming C-S-H formation and identifying factors that affect the formation of C-S-H would provide a methodology to predict its formation quantitatively, by analyzing the content of the critical mineralogical phases in the starting materials. Also, the effects of components such as humic acid in dredged soils are known to limit the strength development of cementitious materials [11,12]. Considering these factors, the objective of this study is to identify the key components affecting strength development, i.e., the formation of C-S-H, in steel slag-dredged soil mixtures.…”

Section: Introductionmentioning

confidence: 99%

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

et al. 2018

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Some of the steel slag from ironworks and dredged soils from marine and waterfront engineering work are partially treated as waste. However, a mixture of these two kinds of waste has the potential to be used as construction materials when mixed, due to chemical reactions forming secondary phases. Utilizing waste of such kind as a resource will help to improve sustainability in society by reducing waste and replacing virgin resources such as cement. Recently, it was reported that mixtures of steel slag and dredged soil hardens under specific conditions. The phase compositions of dredged soils and steel slags vary depending on the quantity of each component, which results in unpredictable strength development of mixtures. The effect of the variations in the components of steel slags and dredged soils on strength development of the mixtures is not yet clear, limiting the utilization of both materials. Understanding the hardening mechanisms of the mixtures will enable the prediction of strength development. Focusing on the variations in the components in steel slags and, especially of dredged soils, this study aims to identify the components in both materials that affect the secondary phase formation that are responsible for strength development. We found support for suggestions that calcium silicate hydrate, C-S-H, is one of the secondary phases responsible for the strength development of the mixtures. From a comparison of two kinds of steel slags and various dredged soils, the amount of portlandite in the steel slags and the amount of amorphous silica in the dredged soils are suggested as a couple of the key components of starting materials involved in the C-S-H formation.

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Section: Introductionmentioning

confidence: 99%

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

et al. 2018

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“…The previous studies mainly used the OPC-based binder to treat soft soil 12,16 , but for the SS, the solidified effect is often poor due to the influence of organic matter 22 . That's because the organic matter may interfere with the hydration and cementation process of binder, which can affect the overall solidification and subsequent disposal [23][24][25][26][27] . Since both the solid and pore fluid of SS are rich in organic matter, including protein, fat, and humus 28 , the influence mechanism of them on the solidification of SS is very complicated and is still under 4 Hubei Key Laboratory of Contaminated Clay Science & Engineering, Wuhan 430071, China.…”

Section: Strength and Microstructure Properties Of Solidified Sewage mentioning

confidence: 99%

Strength and microstructure properties of solidified sewage sludge with two types of cement-based binders

Chen

Zhang³

et al. 2020

Sci Rep

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Solidification treatment with cementitious binder is an effective way to reduce environmental hazards of sewage sludge. Two cementitious binders, i.e., ordinary Portland cement (OPC) and sulfo-aluminate cement (SAC), were compared in this study to treat the sewage sludge. The strength of solidified sewage sludge (SSS) and changes in microscopic characteristics before and after treatment were analyzed through microscopic analysis methods. The effect of organic matter in sludge on the strength of SSS were also discussed. The results showed that the strength of SSS were lower than that of the solidified clay with no organic matter, and the filtrate extracted from the sludge can also weaken the cementation of the two cements significantly. The solidification effect of the OPC on the sludge was lower than that of the SAC evidently. The organic matter in the sewage sludge caused the surface of the soil particles to carry a large negative potential, which interfered with the hydration of the binder and reduced the amount of cementation skeleton formed by the binder hydration products. This resulted in a porous structure with low mechanical strength. The amount of early hydration product formed in the SAC-based solidified samples was higher than that of the OPC-based samples. This was favorable for filling the pores of the solidified samples and increasing their density. SAC had a better compatibility with soft soil containing high organic matter than OPC, and the which provides an effective alternative binder for dealing with sewage sludge.

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“…Moreover, studies on the influence of the composition of binders, curing conditions and methods of testing on major engineering properties such as the unconfined compression strength and one-dimensional compression behaviour of the stabilized product are rife [4,[6][7][8][9][10][11][12][13][14][15]. Only varying degrees of successes have been achieved in the utilization of calcium-based hydraulic binders such as lime and cement in the stabilization process [16]. Some studies have indicated that indeed the cementation process does occur with a formation of strong bonds between the binders and the organic clays leading to better mechanical behaviour despite the presence of organic contaminants in the stabilized product [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Organic Matter on Swell and Undrained Shear Strength of Treated Soils

Abbey

Olubanwo²,

Ngambi³

et al. 2019

JCCEE

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This paper presents a laboratory and statistical study on swell and undrained shear strength of cemented organic clays blended with eco-friendly (by-product) cementitious materials such as ground granulated blast slag (GGBS) and cement kiln dust (CKD). The presence of organic matter in soils can be very problematic especially during construction of infrastructures such as roads and foundations. Therefore, experimental and statistical investigations are crucial to further understand the effect of organic matter on swell and strength performance of soils treated with by-product materials (GGBS and CKD). Five artificially synthesised organic clays with 0%, 5%, 10%, 15% and 20% organic matters were mixed with 20% cement during the first phase of mixing. In the second phase, cement content was reduced to 4% and blended with 12% GGBS and 4% CKD respectively. All mixed samples were cured up to 56days and subjected to undrained triaxial test and onedimensional oedometer swell test. The undrained shear strength of the untreated soils decreases from 22.47kPa to 15.6kPa upon increase in organic matter from 0-20%. While the swell increases from 1.17% to 3.83% for the same range of 0-20% organic matter. The results also show improvement on strength and swell upon addition of 20% cement for all investigated samples. For samples treated with 4% cement and inclusion of 12% GGBS and 4% CKD, the treated soils showed better performance in terms of swell potential due to reduction in plasticity compared to the plasticity of soils treated with 20% cement. Undrained shear strength increases from 632kPa to 804.9kPa and from 549.8kPa to 724.4kPa with reduction in organic matter upon addition of 20% CEM and 4% CEM: 12% GGBS: 4% CKD after 56days. The results obtained show that the inclusion of GGBS and CKD reduced swell and increases undrained shear strength irrespective of the percentage of organic materials due to cementation effect. However, results of the statistical studies show that the presence of organic matter influences the extent of performance of the cement, GGBS and CKD treated soils.

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Influence of Humic Acid on the Strength Behavior of Cement-Treated Clay during Various Curing Stages

Cited by 30 publications

References 21 publications

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

Strength and microstructure properties of solidified sewage sludge with two types of cement-based binders

Effect of Organic Matter on Swell and Undrained Shear Strength of Treated Soils

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