civil engineering
farhad pirmohammadi alishah; mehdi Mohammadrezaei
Abstract
Nowadays, improving problematic soils is considered as one of the geotechnical engineering challenges. Since the problematic soils have a secondary origin that are the results of chemical weathering, they have a wide range of dispersive characteristics. One of these types of soils is clay that causes ...
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Nowadays, improving problematic soils is considered as one of the geotechnical engineering challenges. Since the problematic soils have a secondary origin that are the results of chemical weathering, they have a wide range of dispersive characteristics. One of these types of soils is clay that causes many problems in the engineering project. These problems are related to their specifications, such as week strength, settlement, and dispersivity problems. One of the treatment methods of the mentioned problems is chemical soil stabilization. One of the ways to improve soil quality is to use additives. Due to the widespread use of nanomaterials in different sciences, the impact of these materials as a novel additive can be investigated. In this study, the effect of nanosilica additive on bond strength of clay soils was investigated. In this study, we investigated the effect of nanosilica on unconfined compressive strength of clay soils in Jolfa region using in vitro and uniaxial experiments. Cohesive soil samples were tested by adding different percentages of nanosilica. The results indicate that nanosilica increased the uniaxial compressive strength of the clay soil. The results showed that the percentage of nanosilica additive for optimum compressive strength in clay soil was about 0.8%. Comparison of three series of clay compressive strengths in different percentages of nanosilica additives shows a minimum resistance of about 6 kg / cm2 and maximum resistance of about 9 kg / cm2.
farhad pirmohammadi alishah; Navid Mahmoudzadeh
Volume 2, Issue 5 , August 2020, , Pages 87-109
Abstract
Plastic concrete have been used for some four decades in watertight structures. In these four decades, plastic concrete has been successfully used in engineering control projects for seepage. Plastic concrete is produced by mixing of cement, bentonite, aggregates and water. Presence of bentonite and ...
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Plastic concrete have been used for some four decades in watertight structures. In these four decades, plastic concrete has been successfully used in engineering control projects for seepage. Plastic concrete is produced by mixing of cement, bentonite, aggregates and water. Presence of bentonite and high water-cement ratio is difference between plastic concrete and conventional concrete. These two factor cause plastic concrete, besides possession of water tighting property, have a very lesser comperssive strength and modulus of elasticity in comparsion with conventional concrete and therefore be more deformable. Researches that fulfilled on this type of concrete in the word and especially in Iran, were not extensive and most of done works have been typical studies on relative projects. In order to make more economical plastic concrete, it is necessary to evaluate the effects of changes in the properties of bentonite, and in particular the effect of its plastic index change, and given that there is no extensive research in this field in our country, we try to move toward this goal in this these. Therefore after primary stduies and test, 51 mix designs were teseted and compressive strength, modulus of elasticity and workability of them were determined. Based on the results, with increasing amount of plastic index of bentonite, compressive strength, elasticity modulus and workability decrease.
