China
Africa
Explore chapters and articles related to this topic
Fundamentals of Soils
Published in John E. Schaufelberger, Giovanni C. Migliaccio, Construction Equipment Management, 2019
John E. Schaufelberger, Giovanni C. Migliaccio
While lime is used to stabilize high clay content soils, cement is used to stabilize both granular soils and fine-grain soils. There are two types of cement and soil mixtures: (1) soil-cement and (2) cement-modified soil. Soil-cement contains sufficient cement to form a hardened mixture. It is compacted to a high density and cures into a hardened slab-like structural material. Soil should have a plasticity index of less than 10% for the soil to be a good candidate for soil-cement. Cement-modified soil may be a hardened or semi-hardened mixture depending upon the amount of cement added. The cement reduces the soil’s plasticity and increases its strength, much like lime. Fine-grain soils with plasticity indexes greater than 10% can be stabilized with cement to form cement-modified soil, but generally are not good materials for soil-cement. The amount of cement required to form soil-cement varies from 3% to 8% by weight for sand and gravel to 8% to 15% for fine-grain soils containing clay or silt. The amount of cement required for cement-modified soil usually ranges from 3% to 6% by weight.
Soil
Published in Rajib B. Mallick, Tahar El-Korchi, Pavement Engineering, 2017
Rajib B. Mallick, Tahar El-Korchi
Cement-stabilized soils can be categorized into a few groups: Soil cement, which consists of a mix of natural soil of low or marginal quality (such as natural clay or clayey sand) and cement. The objective of this stabilization is to make such soils usable as subgrade soils. The feasibility of using cement becomes an issue in such cases where the demand for the cement can exceed 20%.Cement treated base (CTB) is a mix of granular materials of reasonably high quality (often they meet base course specifications) and cement, used as high-quality stiff base course in pavements with high loads and traffic volume. The mix can contain wither crushed or uncrushed base course aggregate, or with a blend of both materials. The cement content is generally kept lower than 4% to prevent excessive reflective cracking in pavements.Econocrete, which is a mix of low-quality aggregates (natural or reclaimed aggregates, which do not meet the standard specifications) and cement, used principally as a subbase (such as in airport pavements).
Deep excavations stabilization with ground improvement or cross walls: A comparison of both stabilization methods
Published in Arsenio Negro, Marlísio O. Cecílio, Geotechnical Aspects of Underground Construction in Soft Ground, 2017
The Deep Soil Mixing method (DSM) was invented in Japan and Scandinavia. Its use is growing across the world in strengthening and sealing weak ground. The method helps to achieve significant improvement in the mechanical and physical properties of the existing soil, by mixing with water and cement or compound binders to become a so-called soil-mix (or soil-cement). The stabilised soil material that is produced generally has a higher strength and lower permeability than the in situ soil. The composite ground block is produced with water, soil and cement.
Challenge of adopting relatively low strength and self-cured geopolymer for road construction application: a review and primary laboratory study
Published in International Journal of Pavement Engineering, 2021
Peerapong Jitsangiam, Teewara Suwan, Kedsarin Pimraksa, Piti Sukontasukkul, Prinya Chindaprasirt
Cement can be used as the stabilising agent to produce two classes of cement-stabilised materials: ‘soil-cement’ and ‘cement-modified soil’. Soil-cement is a mixture of pavement base or subbase materials, a small portion of cement, and water, along with the compaction process required to reach a target density. An optimum amount of cement added to such mixtures produces a hardened material with adequate strength and durability to serve as the road pavement base. With the in-situ pavement recycling process, cement-treated recycled pavement aggregates (e.g. recycled pavement asphalt (RAP) and base course materials) are considered soil-cement products (PCA 1992, Austroads 2006, Board et al.2009). Cement-modified soils are a base or subbase material that has been treated with less cement in comparison to that required to produce hardened soil-cement. The aim of cement-modified soils is to only alter the undesirable characteristics of soils or aggregates used in road pavement construction (Austroads 2010, 2014).
Stiffness of artificially cemented sands: insight on characterisation through empirical power relationships
Published in Road Materials and Pavement Design, 2021
Andrea Diambra, Erdin Ibraim, Lucas Festugato, Marina Bellaver Corte
The reinforcement technique based on the mixing of soils with small amounts of cement material is an effective means of improving stiffness characteristics, enabling the reuse of locally available soils in many engineering projects. For example, highly compacted mixtures of soil/aggregate, cement and water are widely used as a low-cost pavement base for roads, residential roads, parking areas, airports and storage zones, among others (e.g. Hein, Rao, & Lee, 2016). Other applications include reinforced excavations, soil-cement columns, jet-grouting, slope protection for embankments and dams, soil-stabilisation below superficial foundations (e.g. Fan, Wang, & Qian, 2018; Sariosseiri & Muhunthan, 2009). The soil material used in soil-cement mixtures can be any combination of clay, silt, sand, gravel or crushed stone. However, higher mechanical performances are expected for non-fine soils, i.e. sands and coarser materials.
Equations controlling the strength of sedimentary silty soil–cement blends: influence of voids/cement ratio and types of cement
Published in International Journal of Geotechnical Engineering, 2021
Jair de Jesús Arrieta Baldovino, Eclesielter Batista Moreira, Érica Carazzai, Eduardo Vieira de Goes Rocha, Ronaldo dos Santos Izzo, Wellington Mazer, Juliana Lundgren Rose
One of the methodologies to improve soil physical–mechanical properties is cement addition. This methodology, which has been employed for 100 years (Firoozi et al. 2017), is adopted to stabilise soils used in pavement layers, reinforcement of soils used as basis of superficial foundations, protection of slopes and declivities, and construction of deep foundations. Soil–cement is defined as a mixture of soil and measured quantities of Portland cement and water, compacted to the desired density. Cement is most commonly used to increase the strength of sandy soils. When water is added to the soil–cement mixture and soon compacted, hydration occurs, which means that calcium silicate hydrate and calcium aluminate hydrate cementing compounds are formed and the excess of calcium hydroxide [CaOH] is released (Ronoh et al. 2014). Lade and Trads (2014) reported the role of cementation in the behaviour of artificially cemented soils based on experimental studies using elastoplastic models. To establish the influence of cementation power on the progress of soil–cement strength, Horpibulsuk et al. (2010), based on microstructural considerations, analysed the strength evolution of the material composed of silty clay mixed with cement, studying the influence of moisture content, curing period and cement amount. Addition of cement improves the soil structure by increasing inter-cluster bonding, therefore reducing pore space. For Horpibulsuk et al. (2010), water influences both the hydration products and the pore sizes, and water is 0.8 times better than the optimal compaction moisture value.