Geotechnical Properties of Some Coal Fly Ash Stabilized Southwestern Nigeria Lateritic Soils

Abstract

This study on stabilization of tropical lateritic soils using self-cementing coal fly ash evaluated the effects of the addition of self-cementing coal fly ash on the engineering properties of three lateritic soils from southwestern Nigeria. The engineering properties investigated were those normally involved in highway design and construction. Increasing percentages (by weight of dry soil) of coal fly ash, ranging from 0% through 15% in 2.5% increments, were added and the geotechnical properties assessed. It was observed, for all the soils, that increasing coal fly ash contents brought about increasing improvements in the plasticity and mechanical properties of the soils. When comparing the average value of the properties at 0% coal ash content to their average values at 12.5% coal ash content, there was a reduction in the liquid limits (from 39.0% to 33.3%), a reduction in the plasticity indices (from 15.3% to 9.3%), a reduction in the optimum moisture contents (from 15.8% to 9.7%) accompanied by an increase in the maximum dry densities (from 1920 to 2180 kg/m 3 ), and an increase in the unsoaked CBR values (from 20.0% to 53.0%). For the stabilization of lateritic soils with coal fly ash, a coal fly ash of 12.5% by weight of dry soil was recommended because the improvements in the soil's properties tapered off at about that percentage of coal ash content.

Weak Soil Modifications Using Sustainable Recycled Municipal Solid Waste Ash

“…The result of the peak value constituted about 4.66% of the initial value (unstabilized laterite). The pattern of increase agrees with findings recorded by Trivedi et al [42], Okunade [35]. The initial increase in MDD can attributed to the fine filler effect of the MSWA in the lateritic soil.…”

“…The observed trend tallied with findings recorded by Varaprasad et al [34]; they however attributed their reduction to the cationic exchange that takes place between the Ca, Al, Si in MSWIA and clayey ions in the soil. The observed trends was also in tandem with findings discovered by Okunade [35] and Amade [29]. However, Asunn et al [36] reported contradicting outcomes interms of plastic limit behavior when laterite was incorporated with RHA and carbide.…”

Fly-Ash-Based Geopolymer as Stabilizer for Silty Sand Embankment Materials

“…With this said, the highest increase in CBR index is 32.64% when compared to the pure soil, which is 1.68%. This is slightly similar to a local study [11] and, studies in Nigeria [12], Germany [13], Sudan [15], USA [16] which applied fly ash on several types of soil. These studies had results wherein the CBR indices increased by 30% to 55%.…”

“…This eventually poses a threat to the environment if it is not properly managed [8]. Consequently, several studies [9], [10], [11], [12], [13], [14], [15], [16] have been conducted, which is aimed towards recycling fly ash and utilizing it in various applications.…”

Potential of snail shell and palm kernel shell powders in improving engineering properties of clay

“…The applicability of these waste by-products has been in various forms. They are used in fiber, ,calcinated ash, shell forms These materials include among others Rice Husk (Oluwatuyi and Ojuri 2017;Phanikumar and Nagaraju 2018), Coconut Shell and Coir (Oyedepo et al, 2015;Sanjay and Rajeev 2015;Ashish Johnson and Krishnankutty 2017), Sugarcane Baggase (Alavez-Ramirez et al, 2012;Abdulkadir et al, 2014;Salim et al, 2014;Danso et al, 2015), Egg Shell (Amu and Salami 2010;Jiksymol et al, 2014;Johns et al, 2017;Karthika et al, 2016;Kavyashree et al, 2016;Okonkwo et al, 2012), Cassava peel (Salau et al, 2012;Bello et al, 2015;Olutaiwo and Adanikin 2016), Groundnut Shell (Nnochiri and Ogundipe 2016;Sujatha et al, 2016), Saw dust (Ogunribido 2012;Ayeni and Ayodele 2015;Butt et al, 2016), Palm Kernel Shell (Edeh et al, 2012;Adetoro and Faluyi 2015;Nnochiri et al, 2017), Fly Ash (Phanikumar and Sharma 2007;Okunade 2010;Phanikumar and Nagaraju 2018), dusts (Sunil et al, 2016;Igwe and Adepehin 2017;Duc and Onyelowe 2018), Bamboo (Amu and Adetuberu 2010;Olofintuyi et al, 2015;Brahmachary and Rokonuzzaman 2018).etc. Few researches have been carried out on using the powder form of the waste except sea shell powder (Mounika, ...…”