Effect of Nano-Additives on the Strength and Durability Characteristics of Marl

Abstract

Low bearing capacity soils may pose serious construction concerns such as reduced bearing capacity and excessive hydro-associated volume changes. Proper soil remediation techniques must be planned and implemented before commencing any construction on low bearing capacity soils. Environmentally friendly soil stabilizers are gradually replacing traditional soil stabilizers with high carbon dioxide emissions such as lime and cement. This study investigated the use of an alternative pozzolanic mix of nano-additives (i.e., nano-silica and nano-alumina) and cement to reduce the usage of cement for achieving competent soil stabilization outcomes. A series of unconfined compressive strength (UCS), direct shear, and durability tests were conducted on marl specimens cured for 1, 7, and 28 days stabilized with nano-additives (0.1~1.5%), 3% cement, and combined 3% cement and nano-additives. The UCS and shear strength of stabilized marl increased with nano-additives up to a threshold nano-additive content of 1% which was further intensified with curing time. Nano-additive treated cemented marl specimens showed long durability under the water, while the cemented marl decomposed early. The microfabric inspection of stabilized marl specimens showed significant growth of calcium silicate hydrate (CSH) products within the micro fabric of nano-silica treated marl with reduced pore-spaces within aggregated particles. The results confirmed that nano-additives can replace cement partially to achieve multi-fold improvement in the strength characteristics of the marl.

Micro to Nanolevel Stabilization of Expansive Clay Using Agro-Wastes

“…Expansive clay subgrade of low bearing capacity is considered as a costly issue [14] for which stabilization is a feasible solution to increase shear strength and to decrease water susceptibility [15]. Furthermore, the expansive clays as subgrade are prone to large settlements resulting in formation of uneven geometry around the embankment [16][17][18]. From geotechnical perspectives in pavements subgrades built with expansive clays, commonly the more important parameters of interest are resilient modulus (MR), elastic modulus (Es), unconfned compressive strength (UCT), and California bearing ratio (CBR) index.…”

“…Environmental friendly microstabilizers derived from agro-wastes are rapidly replacing the traditional microstabilizers for expansive clays [18]. Straw, bagasse, and husk are popular form of agro-wastes used.…”

“…Te nanoparticles cause transformation of pore liquid to viscous gel resulting in enhancement of soil shear resistance. Te nanostabilization of soil improves its structure, physical, and chemical properties due to flling of voids at nanolevel [18]. In addition, the nanostabilization causes enhancement of load bearing potential of soil [33].…”

“…Cost-efective and eco-friendly extraction of nanosilica from RHA can be accomplished by chemical and combustion methods. Reference [18] presented the combined efect of microlevel (cement) and nanolevel (nanosilica) on marl clay and found that nanosilica was four times more efective compared with cement stabilized marl clay.…”

Influence of palm fiber on strength and crack characteristics of red clay

“…Although chemical modification substantially improves the strength of red clay, it concurrently alters the soil pH and potentially harming plant growth. Environmentally friendly soil improved approaches are gradually replacing traditional chemical modifications, such as nano-additives, 10 nano-graphite powder, 11 and fibers. Natural and synthetic fibers have been used to improve problematic soils for a long time, 12 including corn fibers, palm fibers, polypropylene fibers, and grass fibers.…”