Strength and Microfabric of Expansive Soil Improved with Rice Husk Ash and Lime

Expansive/swell-shrink soils exhibit high plasticity and low strength, which lead to settlement and instability of lightly loaded structures. These problematic soils contain various swelling clay minerals that are unsuitable for engineering requirements. In an attempt to counter the treacherous damage of such soils in modern geotechnical engineering, efforts are underway to utilize environmentally friendly and sustainable waste materials as stabilizers. This study evaluates the strength and consolidation characteristics of expansive soils treated with marble dust (MD) and rice husk ash (RHA) through a multitude of laboratory tests, including consistency limits, compaction, uniaxial compression strength (UCS), and consolidation tests. By using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, the effect of curing on UCS after 3, 7, 14, 28, 56, and 112 days was studied from the standpoint of microstructural changes. Also, the long-term strength development of treated soils was analyzed in terms of the interactive response of impacting factors with the assistance of a series of ANN-based sensitivity analyses. It is found from the results that the addition of MD and RHA lowered down the water holding capacity, thereby causing a reduction in soil plasticity (by 21% for MD and 14.5% for RHA) and optimum water content (by 2% for MD and increased by 6% for RHA) along with an increase in the UCS (for 8% MD from 97 kPa to 471 kPa and for 10% RHA from 211 kPa to 665 kPa, after 3 days and 112 days of curing, respectively). Moreover, from the oedometer test results, m v initially increased up to 6% dosage and then dropped with further increase in the preconsolidation pressure. Furthermore, the compression index dropped with an increase in the preconsolidation pressure and addition of MD/RHA, while the coefficient of permeability (k) of RHA stabilized soil was higher than that of MD-treated samples for almost all dosage levels. The formation of the fibrous cementitious compounds (C-S-H; C-A-H) increased at optimum additive dosage after 7 days and at higher curing periods. Hence, the use of 10% RHA and 12% MD as replacement of the expansive soil is recommended for higher efficacy. This research would be helpful in reducing the impacts created by the disposal of both expansive soil and industrial and agricultural waste materials.

Section: Introductionmentioning

confidence: 99%

Strength, Hydraulic, and Microstructural Characteristics of Expansive Soils Incorporating Marble Dust and Rice Husk Ash

Jalal

Mulk

Memon

et al. 2021

“…RHA in the proportions of 3%, 6%, 9%, and 12% and NS in the proportions of 0.6%, 0.9%, 1.2%, and 1.5% were mixed in C to prepare samples for determination of swell potential, unconfned compressive strength (UCT), resilient modulus, and California bearing ratio (CBR). Te proportion of RHA and NS was selected keeping in view the typical guideline range of these materials mixed with clay from previous studies [12][13][14]32]. Tables 1-3 show the test matrix details used in experimentation.…”

Section: Methodsmentioning

confidence: 99%

“…Te chemical analysis shows that the 35% cellulose, 35% hemicellulose, 20% lignin and 10-20% ash can be obtained from of rice husk on dry weight basis [31]. RHA can be used as green additives due to its high pozzolanic activity [32]. RHA is produced by the burning of rice husk at about 600 °C in which high quantity of silica, low quantity of oxide and high specifc surface is observed.…”

Section: Introductionmentioning

confidence: 99%

Micro to Nanolevel Stabilization of Expansive Clay Using Agro-Wastes

Munawar

Khan

Rehman

et al. 2023

The circular economy encourages the production and consumption of sustainable embankment geomaterials and their blends utilizing recycled waste materials in roads, railway tracks, airfields, and underground structures. Geomaterials comprising high-plastic soft expansive clay pose excessive settlement during cyclic traffic/railway/airfield loading resulting in uneven geometry of overlying layers. This paper demonstrates multiobjective optimized improvement of expansive clay (C) geotechnical characteristics by cost-effective agro-wastes additives at microlevel (by 3% to 12% rice husk ash, i.e., RHA), nanolevel (by 0.6% to 1.5% rice husk derived green nano-SiO2, i.e., NS), and synergistic micro to nanolevel (NS-RHA). The swell potential, resilient modulus (MR), initial elastic modulus (Es), unconfined compressive strength (UCT), and California bearing ratio (CBR) of C and its blends were determined. The chemical characterization of C and its blends were conducted through Fourier transform infrared spectroscopy (FTIR) and optical microscopic tests. The outcome of this study depicted that the cost ratio for the optimized composite, i.e., (1.2% NS-9% RHA)/(9% RHA) is 1.22 whereas stiffness ratio MR (NS-RHA)/MR(RHA) and Es (NS-RHA)/Es(RHA) and strength ratio UCT(NS-RHA)/UCT(RHA) and CBR(NS-RHA)/CBR(RHA) were found to be 2.0, 1.64, 2.17, and 2.82, respectively. FTIR revealed the chemical compatibility between C, RHA, & NS from durability perspective. Cost-stiffness results of this study can be applied by geotechnical experts to economize the green stabilization of C by use of agro-waste for sustainable development.

“…CA is formed when coral reef-building organisms deposit vast amounts of calcium carbonate (CaCO 3 ). Calcium carbonate (CaCO 3 ), which contains a similar chemical composition to cement, can be used in place of some of the cements in concrete [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Effect of Coral Aggregates of Blended Cement Concrete Subjected to Different Water Immersion Condition

Bunyamin

Kurniasari

Munirwan

et al. 2022

The increasing use of concrete in construction has caused an increase in the need for resources for concrete mixtures and driving wide-scale mining. One alternate material that can be used for aggregates replacement is coral. Coral aggregates (CA) have similar chemical characteristics to cement. The compressive strength and tensile splitting strength tests of concrete coral aggregates were performed based on the ASTM and ACI standards. This study aims are to investigate the usage of CA as a partial replacement of cement and fine aggregate to increase the strength of concrete at substitution percentages of 0, 5, 10, and 15%. Two different water submerged scenarios of distilled water and salt sea water immersion were applied. The concrete strength test was carried out after 28 days of curing time, with the specified concrete quality of 17 MPa. The results showed that immersion in distilled water has a higher concrete strength than immersion in sea water. The maximum compressive strength of concrete for distilled and sea water immersion is for 0% CA content of 18.47 and 14.89 MPa, respectively. Moreover, the highest value of the split tensile strength of concrete with distilled and sea water immersion is for CA substitution of 5% of 2.52 and 2.5 MPa, respectively. The addition of 5% coral aggregates to cement and fine sand is the optimum combination since it increases the maximum split tensile strength of concrete.