Strength and microstructure development in Bangkok clay stabilized with calcium carbide residue and biomass ash

Abstract

A mixture of biomass ash (BA) and calcium carbide residual (CCR) was used as a cementing agent for stabilization of soft Bangkok clay. The improvement in unconfined compressive strength of stabilized clay depends on the initial soil water content, binder content (B), CCR:BA ratio, and curing time. The strength improvement can be classified into two zones: active and inert. In the active zone (B = 5-15%), the Ca(OH) 2 content from the CCR is high and there are insufficient natural pozzolanic materials in the clay for the reaction. The input of BA increases the SiO2 content and induces the strength development. In the inert zone, (high binder content, B > 15%), the free lime causes unsoundness and results in insignificant strength development. The hydration products from the pozzolanic reaction (ettringite and a calcium aluminate silicate hydrate compound, gismondine) are identified by microstructural analysis via X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray spectroscopy (SEM with EDS), and X-ray fluorescence. SEM images show the compact morphology of the stabilized clay as the result of the increase in curing time and binder content. Over time, the cementitious products fill in the pore space, causing denser morphology and higher cementation bond strength between the clay clusters. The clay stabilized by XRD showed no reduction in the intensity of the reflection of the both quartz and kaolinite throughout the curing times. This implies that the amorphous silica from the glass of the BA is more reactive in dissolution in the CCR than the crystalline phase of quartz and kaolin in clay.

The Importance of Clay in Geotechnical Engineering

“…For this reason, geotechnical engineering studies are interested in the physical and mechanical behavior of soils-bearing structures, as well as the strength between the structure, texture and performance of soils. There are many studies The Importance of Clay in Geotechnical Engineering http://dx.doi.org/10.5772/intechopen.75817 on the soil-orientation effects on the soil properties such as strength, hydraulic conductivity and the swelling-shrinkage relative to each particle [7][8][9][10][11][12]. Ingles [7] examined soil fabric during consolidation.…”

Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

“…Biomass ash also works as ac ementing agent in combination with CCR, fore xample, in stabilization of soft Bangkok clay. [153] The mechanical strength of stabilized clay dependso n its initial water content,b inder content,c uring time, and CCR to biomass ash ratio. The unconfined compressive strength of www.chemsuschem.org the clay at 150 days reaches 1400 kPa with the optimal amount of water and 6:4C CR to biomass ash ratio ( Figure 39).…”

“…Biomass ash also works as a cementing agent in combination with CCR, for example, in stabilization of soft Bangkok clay . The mechanical strength of stabilized clay depends on its initial water content, binder content, curing time, and CCR to biomass ash ratio.…”

“…[166] In addition to strengthening/stabilization,F As ignificantly improves the resistance of soil to the absorption of water.V arious OPC-free CCR-FAm ixtures weret rialed to enhance the strength of ap roblematic silty clay in Thailand, [150] for problematic soil stabilization, [150,167] soft marine clays tabilization, [168] and for the manufacture of nonbearing masonry units. [169] Nonbearing masonry units werea lso experimentally made from CCR [150] FA [150] Silty clay [150] Hydrated lime [150] BA [151] Rice husk [152] Biomass ash [153] OPC [154] WTS [155] Bottoma sh [156] [155] The CCR-FAm ixtures provedt ob es trong enough to transform demolition waste (concrete aggregates,c rushed bricks, etc.) into building material.…”

Justification of strength properties of microstructural changes in the black cotton soil stabilized with rice husk ash and carbide lime in the presence of sodium salts

“…Strength of BC soil treated with lime is more on the dry of optimum due to the existence of the flocculated structure, and also enhancement in the strength is observed with the addition of two other materials such as RHA and lime [5,6]. The addition of industrial and agro-industrial waste such as carbide lime-biomass ash mixture, fly ash and lime mixture along with salts acts as a cementing agent for improving strength of a clayey soil [7][8][9][10][11]. This leads to the development of a large volume of alkali silicates and aluminate hydrated products as opposed to calcium hydrated products.…”