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Sulfate-rich dispersive soils are a major concern due to their high susceptibility to erosion and heave, related to high amounts of adsorbed Na+ ions and the formation of expansive minerals derived from reactions involving sulfates and calcium, respectively. In this sense, the development of alternative treatments to overcome such problems must be sought, since the application of lime and/or Portland cement by themselves has proven to be ineffective. Thus, the present paper proposes a binder composed of carbide lime and ground glass waste combined with fiberglass reinforcement to stabilize such soils. The efficiency of the proposed alternative towards reduction of swelling was assessed through 3-D volumetric swell tests carried out on compacted soil-binder-fiberglass blends molded with multiple different dosages. The results have shown that the porosity and the amount of carbide lime influenced the volumetric strain (εv) of the tested specimens greatly. The influence of porosity was inversely proportional, while the influence of the amount of carbide lime was directly proportional. The addition of fiberglass was shown to be ineffective. Thus, the εv was successfully correlated to the adjusted porosity/lime index (η/Liv), proving the innovative character of the approach applied herein and enabling the prediction of the εv for different dosage options. [ABSTRACT FROM AUTHOR]

Fibre addition and Portland cement treatment are used to amend the adverse characteristics of some fine-grained soils and to enhance their mechanical properties. The present study proposes a single power function that quantifies the effects of the amount of cement and porosity on the unconfined compressive ( qu) and split tensile ( qt) strength of fibre-reinforced fine-grained soil-cement mixtures. The practical value of the equation is that only one unconfined compression (or split tensile) test of a specimen moulded with a specific fibre type, fibre amount, specific cement amount, porosity, and cured for a given time period is required to estimate the strength of the fibre-cement soil mixture. The equation can be used for a wide range of porosities and cement contents, and for other fibre-reinforced fine-grained soils treated with cement. [ABSTRACT FROM AUTHOR]

This paper provides a theoretical derivation for the unconfined compression strength of artificially cemented granular soils. The proposed developments are based on the concept of superposition of failure strength contributions of the soil and cement phases. The granular matrix obeys the critical state soil mechanics concept, whereas the strength of the cemented phase can be described using the Drucker-Prager failure criterion. In the process, the analytical relation is suitably adjusted to parallel a recently proposed empirical relationship that links unconfined compression strength of artificially cemented granular soils to an adjusted porosity/cement ratio parameter. Although the proposed analytical relation fits the experimental data for different granular soils and cement curing time well, further parametric analysis offers the possibility of exploring the effect of some material parameters on the unconfined compression strength of artificially cemented granular soils. [ABSTRACT FROM AUTHOR]

An effort is being carried out to develop dosage methodologies for improved soils based on a rational criterion, as in concrete technology, where the water/ cement ratio plays a fundamental role in target strength assessment. This study aims to assess the strength-controlling parameters of a sandy lean clay treated with lime or cement, and to show that the void/cementitious material content ratio plays a fundamental role in target strength assessment. The controlling parameters evaluated were the amount of cementitious material, the porosity, the moisture content, and the void/ cementitious material ratio. A number of unconfined compression tests and suction measurements were carried out in the present work. The results show that the unconfined compressive strength (UCS) increased linearly (with a reduced strength gain rate) with lime content for soil-lime mixtures. A power function fits the UCS-cement relationship better for soil-cement mixtures. The UCS increased linearly with the reduction in porosity for soil-lime mixtures and exponentially for soil-cement mixtures. Finally, the porosity/volumetric cementitious material content is shown to be a good parameter in the evaluation of the unconfined compressive strength of the soil studied. [ABSTRACT FROM AUTHOR]

The article offers information on a study that the influence of lime content and porosity on the Mohr-Coulomb failure envelopes of lime-treated soils. Topics discussed includes pozzolanic reactions, application of methodology to a soil with different characteristics and shear resistance angle obtained by the triaxial tests.