Research of Soil-Concrete Material and its application for the Production of Piles and Soil Strengthening

ABSTRACT

The results of the research of soil-concrete strength characteristics and frost resistance depending on cement gauging, mixture density, soil type etc. are presented in the article.

According to the results it has been stated that the rise of cement gauging from 5% to 30% leads to the compressive strength improvement Rсж of soil-concrete samples by 70-90%.

Thus the value of the indicator Rсж at the age of 90 days on average is 1,5-2,5 times higher of the value of the indicator Rсж at the age of 28 days. It’s necessary to highlight that the samples, that have been preserved in water, show the most high value of the indicator Rсж.This leads to the conclusion that the arrangement of soil-concrete piles in water-deposited soils is favorable. The density of a sample has the essential influence on soil-concrete strength. Increasing density it is possible to reduce the expenditure of cement up to 50%. Soil-concrete density is the basic factor that influences the increase of frost-resistance of the material.

The value of the indicator Rсж depends mostly on soil characteristics, in particular – on grain size composition. For example, under equal initial conditions (expenditure of cement, water, mixture density and so on) the strength of soil-concrete made on the basis of sandy silt is 1,5 times lower than the one made on the basis of medium coarse sand or sandy clay.

The soil-concrete made on the basis of sand, clay-bearing soil (sandy soil, sandy clay) is a frost resistant material. Frost resistance as well as density increases through time and depends on cement expenditure. 35 cycles of “frosting-defrosting” for all types of the soils under research are provided with the cement expenditure at the amount of no less than10% (to the weight of airy dry soil). No less than 50 cycles are achieved for the soil-concrete materials made of medium coarse sand, sandy soil and sandy clay with the cement gauging at the level of 15-20%, for the ones made of sandy silt – 25%.

With cement gauging lower than 15% the decrease of sample density by 5-10% and of compressive strength – by 20-40% (depending on the type of soil) was observed for all types of samples after 20-30 cycles.

In terms of the research carried out in laboratory and real-life conditions of testing on the factory floor during piles erection, technical, constructive and design requirements to soil-concrete used for piles production (strength, water resistance, frost resistance, expenditure of materials, methods of arrangement, quality and acceptance control) are elaborated. Economy up to 50%.

Keywords: soil-concrete, density, frost resistance, strength, foundations, recommendations, saving

For citation: Kravtsov V. Research of Soil-Concrete Material and its application for the Production of Piles and Soil Strengthening. Contemporary Issues of Concrete and Reinforced Concrete: Collected Research Papers. Minsk. Institute BelNIIS. Vol. 7. 2015. pp. 53-64.

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References:

1. Tokin A. N. Fundamenty iz tsementogrunta [Foundations of soil cement]. Мoscow: Stroyizdat, 1984. – 184 p. (rus)
2. Krutov V. I., Bagdasarov Yu. A., Rabinovich I. G. Fundamenty v vytrambovannykh kotlovanakh [Foundations in rammed basins]. Мoscow: Stroyizdat, 1985. – 163 p. (rus)

ISSN 2076-6033