scholarly journals Study on the Stabilization of a New Type of Waste Solidifying Agent for Soft Soil

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 826 ◽  
Author(s):  
Jiansheng Shen ◽  
Yidong Xu ◽  
Jian Chen ◽  
Yao Wang

The use of desulfurization gypsum and steel/furnace slag composite cementitious material (DGSC) to solidify soft soil can fully utilize industrial wastes, reduce cement use and protect natural resources. By studying the unconfined compressive strengths of DGSC-solidified soil with different mix ratios, water-binder ratios and curing periods, the influence of those factors on the unconfined compressive strength of the soil can be analyzed. Furthermore, the quasi-water-cement ratio is introduced to predict the strength of the DGSC-solidified soil. The results show that the higher the DGSC content is, the better its effect on the soft soil. The variation in the unconfined compressive strength of DGSC-solidified soil overtime can be described by the same trend as that of cement-solidified soil but its early strength is lower than that of cement-solidified soil. When the water-binder ratio of the DGSC-solidified soil is the same as that of the cement-solidified soil, after a28-day curing period, the content of DGSC is higher than that of the 5% cement content, so the DGSC solidification effect is comparable to that of cement. Therefore, using DGSC instead of cement as a soft soil solidifying agent can meet the strength requirements of solidified soil.

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chen Wang ◽  
Wentao Li

A study has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined compression test and the tensile test. Basic factors including the curing period, the water-binder ratio, the cement content, and the strain rate were evaluated. Ordinary Portland cement with fly ash was employed as the cementation agent for preparing cemented samples. The results indicate that the unconfined compressive strength, the deformation modulus, and the tensile strength increase with the increase in the curing period. The ratio of tensile strength to unconfined compressive strength has no distinct change after 7 days. An optimum water-binder ratio can be obtained. The unconfined compressive strength and deformation modulus decrease as the water-binder ratio decreases and increase from the optimum water-binder ratio. With the increasing of the cement content, the unconfined compressive strength increases distinctly, the deformation modulus increases significantly when the cement content is less than 4% and then increased slowly, and the failure strain increases to a peak value and then decreases. With the increasing of the strain rate, the unconfined compressive strength increases slightly and the deformation modulus increases slowly. The failure strain decreases with an increase in the strain rate.


2019 ◽  
Vol 814 ◽  
pp. 399-403
Author(s):  
Anuchit Uchaipichat

This paper presents the relationship between the dynamic cone penetration (DCP) test results and the unconfined compressive strength of lateritic cemented soils. A series of DCP tests and unconfined compressive strength was performed on lateritic cemented soil. The soils sample used in this study was lateritic soil. The test results for the DCP tests are presented in terms of penetration index. It can be observed that the penetration index decreased with increasing curing period and cement content. Moreover, the unconfined compressive strength of cemented soils increased with curing period and cement content. The relationship between unconfined compressive strength and penetration index is presented. A unique relationship for unconfined compressive strength can be obtained.


2021 ◽  
Vol 1042 ◽  
pp. 145-150
Author(s):  
Anuchit Uchaipichat

This research investigated the compressive strength of cemented soils admixed with saturated granular activated carbon (GAC). The saturated GAC was obtained from the water filtration system. A series of unconfined compressive strength was performed on both compacted soil-cement specimens and compacted soil-GAC-cement specimens with GAC content of 30 percent. All specimens were prepared by compaction with energy equivalent to the modified Proctor test. The results from modified Proctor tests showed that the maximum dry unit weight and the optimum moisture content of soil-GAC sample was less than those of soil sample. From the unconfined compression tests, there was tiny development of strength for both types of specimens with cement content of 1 percent throughout the curing period of 28 days. For both types of specimens with cement content of 2 and 3 percent, the significant development of strength occurred after curing for 3 days. The strength of specimens typically increased with increasing cement content. Generally, the strength of compacted soil-GAC-cement specimens was less than that of compacted soil- cement specimens. It was also observed that the relationships between normalized compressive strength ratio and curing period was unique for the specimens with the same cement content.


Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 302
Author(s):  
Yaxu Liu ◽  
Zhuang Liu ◽  
Erwin Oh ◽  
Dominic Ek Leong Ong

The study of the strength of reconstituted and stabilised soft soils is very important in geotechnical engineering. The soil particles, such as clay, sand, and silt play important roles in determining the behaviour of soils. The behaviour of clay and sand particles are unique; however, the behaviour of silt particles lie in a transitional form between sand and clay. Therefore, this paper seeks to investigate (a) the effect of silt contents on the strength of soft soils; (b) the effect of silt content on the strength of cement-stabilised soft soils; and (c) the microstructure of the soft soil specimens stabilised by cement with varying particle size distribution. A series of tests consisting in consolidated, isotropic undrained (CIU) triaxial tests, unconfined compressive strength (UCS) tests, and scanning electron microscope (SEM) images were conducted in this study to achieve these objectives. In conclusion, the relationship between the silt content and critical state behaviour of soft soils (both clay and silt particles) are proposed. For the cement-stabilised specimens, the unconfined compressive strength increases with the increase in silt content when the cement content is 10%. However, the UCS decreases with the increase in silt content when cement content is 30%. With cement content ranging from 15–25%, the UCS increases at first with the increase of silt content but decreases once the silt content reaches a ‘saturation’ point.


This paper discussed the effect of polypropylene fibre and curing period on the unconfined compressive strength (UCS) of cemented-black cotton soil. Various combinations of polypropylene fibres and cement have been taken and the UCS values of the treated black cotton soil specimens were determined after 3, 7 and 28days of curing. The study divulged that the mixing of polypropylene fibre increases UCS of cemented-black cotton soil. The rise in strength depends on the curing period. The 28days strength is 50 to 90% more than the corresponding 3days strength. The maximum enhancement of UCS from 969 to 2431kPa is achieved by adding 1% polypropylene fibre in cemented-black cotton soil having 15% cement after a curing period of 28days. The UCS of cemented-soil with 5% cement content, (Cc) and 1% polypropylene fibre is 781kPa which corresponds to the UCS of cemented-black cotton soil with 12% cement alone after a curing period of 28days. Thus, polypropylene fibre might be an economical admixture to enhance the performance of soil-cement column stabilised black cotton soil.


2014 ◽  
Vol 600 ◽  
pp. 367-374
Author(s):  
Belkacem Menadi ◽  
Said Kenai ◽  
Sihem Hammat ◽  
Jamal M. Khatib

Self-compacting concretes are extremely fluid concretes that can be placed into formwork without vibration. They are characterized by the presence of mineral additions which influence considerably their behavior in fresh and hardened states. This paper reports the results of an experimental study on the influence of Ground Granulated Blast Furnace Slag (GGBFS) and natural pozzolana (NP) and the effect of their fineness on the compressive strength and shrinkage of self-compacting mortars. Each addition was ground to three finenesses 350, 420 and 500 m2/kg. The cement is substituted by 0%, 15% or 30% of GGBFS. The water to binder ratio was kept low at 0.40; cement content and superplasticizer were maintained constant for all mortars mixtures. The results show that the substitution of cement by mineral additions (slag and natural pozzolana) generates a reduction of the total shrinkage (at 28 days) and compressive strength of self-compacting mortars, whatever the fineness of the addition. The study also showed that the increase of the fineness of the natural pozzolana gives an increase in both drying shrinkage and compressive strength. However, the increase of the fineness of slag decreases slightly the shrinkage and the compressive strength of self-compacting mortars.


2020 ◽  
Vol 27 (3) ◽  
pp. 61-66
Author(s):  
Yaseen Yaseen ◽  
Jawdat Abbas

Using industrial waste materials in the treatment of problematic soils is an environmentally friendly and cost-effective technique. It helps in decreasing disposal issues induced by various industrial wastes. Also, it is crucial to understand the behaviour of these waste products before use. This paper presents experimental research in the treatment of expansive soil by the utilization of iron furnace slag. Laboratory program was performed to examine the effect of iron furnace slag on enhancing the engineering properties of expansive soil. Several tests included liquid limits, plastic limits, free swell percentage, swelling pressure, and unconfined compressive strength were conducted on untreated and treated soils. The efficiency of adding 0, 2, 4, and 6 percentages of iron slag to the soil was investigated. The results of the natural and iron slag stabilized soils showed that iron slag has a notable effect on strength parameters and considerable improvement in plasticity and swelling properties. The addition of iron slag to the soil increased the unconfined compressive strength while reduced the swelling potential of soil. It is concluded that the utilization of iron slag to improve the properties of expansive soil is successful and useful


2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247599
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Yong Yi ◽  
Tian Tian ◽  
Kejia Yuan ◽  
...  

The vertical vibration compaction method (VVCM), heavy compaction method and static pressure method were used to form phyllite specimens with different degrees of weathering. The influence of cement content, compactness, and compaction method on the mechanical properties of phyllite was studied. The mechanical properties of phyllite was evaluated in terms of unconfined compressive strength (Rc) and modulus of resilience (Ec). Further, test roads were paved along an expressway in China to demonstrate the feasibility of the highly weathered phyllite improvement technology. Results show that unweathered phyllite can be used as subgrade filler. In spite of increasing compactness, phyllite with a higher degree of weathering cannot meet the requirements for subgrade filler. With increasing cement content, Rc and Ec of the improved phyllite increases linearly. Rc and Ec increase by at least 15% and 17%, respectively, for every 1% increase in cement content and by at least 10% and 6%, respectively, for every 1% increase in compactness. The higher the degree of weathering of phyllite, the greater the degree of improvement of its mechanical properties.


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