Enhancing the Engineering Properties of Subgrade Materials Using Processed Waste: A Review

Abstract

Subgrade materials refer to the original ground underneath a road pavement, when these materials are made up of expansive soil it is referred to as expansive subgrade. Sometimes, these materials do not have sufficient capacity to support the weight of the road pavement and traffic load, which means they require some form of modification and re-engineering to enhance their load capacity. Chemical modification techniques using traditional stabilisers (such as cement and lime) have proved to be an effective means of subgrade stabilisation. However, high costs and environmental concerns associated with the use and production of these additives have highlighted the need for more sustainable and environmentally friendly substitutes. This study reviews the use of industrial by-products and other waste materials used for subgrade stabilisation, focusing on the sustainability of using processed wastes and how they alter the engineering properties of weak subgrade, compared to the use of cement and also reviews the availability of processed waste materials in quantities sufficient to meet the current demand for subgrade stabilisation. The findings illustrate that, processed waste is less expensive and has better sustainability credentials compared to cement. Moreover, processed wastes are available in sufficient quantities to meet existing demands for subgrade stabilisation. Therefore, it is recommended that the use of processed wastes should be promoted and utilised to improve and enhance the geotechnical properties of weak subgrade materials where possible.

Experimental study on potential suitability of natural lime and waste ceramic dust in modifying properties of highly plastic clay

“…The second alternative might be effective option incase availability of one of the materials matters. Besides, the combined application of the stabilizers is of paramount importance especially not to miss advantage of the better performing material [ 4 ]. Furthermore, combined stabilization approach in many cases is more effective than the separate consideration of stabilizers not only from degree of improvement view point but also with respect to having variety of chemical compositions within the blend [ 22 ].…”

“…The expansive behavior of highly plastic subgrades results in development of excessive and permanent deformation in the road structure during its service life [ 3 , 22 ]. Likewise, roads built on this type of subgrade, unconditionally experiences premature failure and pavement distresses [ 4 ]. Due to its low consistency, expansive soil is proscribed as unsuitable material for construction of road pavement [ 5 , 19 , 39 ].…”

The use of fine portions from construction and demolition waste for expansive soil stabilization: A review

“…CDW between ranges of particle sizes differs in compaction behaviour and also shows difference in resistance to permanent load with a slight reduction in permanent deformation. Compacted 100% bricks and concrete fines as subbase materials are considered as minimum strength requirement for most regions and the recorded percentage swells for all subbases are less than 0.13% which can be considered negligible [76].…”

“…There is a general trend of reduction of UCS values for CDW. However, the trend also shows that increase fine particles provide more durable arrangement between the grains and voids and encourages higher values of UCS [76,77]. Table 8 shows replacement ratios of CDW for the replacement of cement based on particles reducing the void and increasing the strength.…”

Strength Behaviour of Expansive Subgrade Soil Stabilized with Coronus Material

“…It is therefore critical that foundation soil has the strength and ability to support external loads acting on the soil. Traditionally, soil stabilization techniques have been effective in stabilizing the clayey soil thus improving the characteristics of soil and its behavior [1]. Clayey soils have often been the bane of civil engineers in general due to it's difficult characteristics.…”