An Experiment and Study of M30 Grade of Concrete by Partially Replacing Fine Aggregate with Marble Dust Powder and Phosphogypsum in Rigid Pavement

The Project is to study about M30 grade of concrete by adding waste materials. Marble dust powder and phosphogypsum which is easily available marble which are standard among the most imperative materials, utilized as a part of the development business. Marble dust is a waste material from the construction site is mixed with concrete as a replacement material. Marble dust powder is acquired from sawing and moulding of marble rock. Phosphogypsum is produced as an outgrowth of the production of fertilizer from phosphate rock. There is a high gypsum content and gypsum is a widely used material in constructions. It is weakly radioactive in nature because it is a by-product of phosphate fertilizers. In the M30 grade of concrete fine aggregate is partially replaced by marble dust powder and phosphosgypsum in some proportions. The fine aggregate is replaced by 10%, 20% and 30% in which marble dust powder and phosphogypsum and are added in an equal proportion. Keywords: Marble dust powder, phosphogypsum, grade of concrete, rigid pavement, green concrete.

Forecasting the Compressibility Parameters of Gypseous Soil using Artificial Neural Networks

To ensure safe design of structures against settlement, it is necessary to determine the compressibility parameters of the underneath soil especially compression and rebound indices. In this paper, an approach to forecast the compressibility parameters of gypseous soils based on index parameters was developed using Artificial Neural Networks technique. Two equations were developed to estimate compression and rebound indices using back propagation algorithm to train multi-layer perceptron, in which good agreements were achieved. The input parameters used were: the depth, gypsum content, liquid limit, plastic limit, plasticity index, passing sieve No.200, dry unit weight, water content and initial void ratio. Two output parameters were determined including compression index and rebound index. A parametric study was also conducted to investigate the generalization and robustness of both models. The findings indicate that both models were reliable within the range of utilized data. It was found that gypsum content has the highest effect on the compressibility index followed by water content, plasticity index, dry unit weight and plastic limit, while other parameters have lower effect. The gypsum content has the highest effect again on the rebound index followed by passing sieve No.200, initial void ratio, plastic limit and plasticity index, while other parameters have lower effect.

Reducing Settlement and Collapse of Gypseous Soil Using Geotextile Reinforcement

Collapsible soils are problematic soils that have substantial strength while dry but lose strength when wet, resulting in excessive settlements. Soil collapse occurs when increasing moisture weakens chemical or physical connections between soil particles, allowing the soil structure to collapse. The existence of these soils, often with significant gypsum concentration, created serious challenges for structures and major projects. The primary goal of this study is to conduct a series of model tests subjected to static vertical stress to assess the ability of soil stabilization using geosynthetics material by employing single, double, and triple geotextile layers put at various places. A unique model test configuration was employed for this testing. The gypseous soil used was brought from near Sawa Lake by coordinates (31◦18′42.83″N, 45◦00′49.36″E) in Al-Muthanna Governorate. The gypsum content was more than (37%). It was found that, the ultimate bearing capacity of dry and wet gypseous soil models had been determined by using Two Tangent Intersection technique. The results show the Settlement Reduction Factor (SRF) % and the ratio of decreasing the collapse magnitude (Δed )

Effects of Fluorogypsum and Flue-Gas Desulfurization Gypsum on the Hydration and Hardened Properties of Alkali Slag Cement

In order to explore the influence of the types of waste gypsum on the properties of alkali slag cement, fluorogypsum (FG) and flue-gas desulfurization (FGD) gypsum were comparatively investigated. Moreover, the action mechanisms of FG and FGD gypsum on the properties of alkali slag cement were analyzed. The results show that both the FG and FGD gypsum prolonged the setting time of the alkali slag cement paste. However, the prolongation effect of FG was more pronounced than the FGD gypsum. When the compressive strength was maximum, the contents of FG and FGD gypsum were 5 and 6 wt.%, respectively. At 3 and 28 days, compared to the control sample, the compressive strengths increased by 59.3% and 24.3%, and 66.9% and 33.9%, respectively. Furthermore, the XRD, TG-DTA and SEM-EDS results showed that, with the increase in the contents of FG and FGD gypsum, ettringite was more easily produced and the hydration products were more abundant in the system. The greater the gypsum content of the paste, the less accumulated was the heat of hydration. The change of micro-structure caused by the formation of ettringite was the main reason for the difference in the properties of cement.

Experimental Study on Early Age Characteristics of Lime-GGBS-Treated Gypseous Clays under Wet–Dry Cycles

Gypseous soils are capable of presenting ground construction challenges to civil and geotechnical engineers due to their unpredictable deformation characteristics. These undesirable responses are sometimes caused by environmental changes in moisture content due to temperature variations, fluctuation of underground water table, surface water, and gypsum content. Hence, the adoption of effective and economical means of stabilising gypseous soils is imperative. This study’s focus is on the early age strength and microstructural characteristics of gypseous soils treated with lime and GGBS. Treated and untreated gypseous soils with 5%, 15%, and 25% gypsum content were subjected to wet–dry cycles while investigating unconfined compressive strength (UCS), water absorption, pH, microstructural changes, and swell. The analysis of the results shows that at zero cycle, the UCS of the untreated gypseous soils increases from 0.62 to 0.79 MPa and swell decreases from 69 to 23%, respectively, as gypsum content increases. However, upon subjection to wet–dry cycles, the UCS reduced from 0.16 to 0.08 MPa at the end of the sixth cycle due to dissolution of gypsum within the soil pores which reduced the strength. The result also shows that gypsum content increases water absorption and reduces the pH of the untreated gypseous soils because of the neutral pH of gypsum. Furthermore, lime-GGBS-treated gypseous soils maintained a higher pH after six wet–dry cycles compared to untreated gypseous soils due to the high pH of lime and the increase in calcium content which improved bonding. In addition, microstructural analysis using SEM indicated early age precipitation of cementitious compounds (CSH) for increasing strength of lime-GGBS-treated gypseous soils compared to untreated gypseous soils.

The history of the forming and the features of the soil, lithological and geomorphological structure of the Jizzakh steppe as the basais for its natural zoning

The paper provides initial materials characterizing the complicated history of formation, natural soils and lithological-geomorphological conditions of the Jizzakh steppe before the beginning of reclamation development. It is shown that on the basis of soil-lithological and geomorphological zoning, the Jizzakh steppe is divided into a number of natural regions belonging to different levels (altitude levels) of the piedmont plain. In total, 22 districts have been identified within the Jizzakh steppe, including the foothill margins. On the piedmont plain itself, the regions are combined into two high-altitude levels: the upper step and the lower step or blanket zone. These two levels differ sharply in terms of drainage conditions and soil salinity. The upper level, covering the upper and middle parts of the alluvial fan, the high interconal Zaamin-Sanzar plain and the Lomakino plateau, is characterized by a weak manifestation of salinity due to relatively good drainage, except for the sloping depressions of the Lomakino plateau. In contrast to the upper level, the lower level, located in the blanket zone of the piedmont plain, is characterized by active natural salinization because of the poor drainage. The saline sediments of the Zaamin cone delta are characterized by the greatest thickness. To a lesser extent, the rocks of the Sanzar cone delta, which are drained by deep gullies, are salinized. The Khavast sloping plain is characterized by a strongly saline upper two-meter layer, with salt and gypsum content decreasing with depth. Thus, it is shown that high salinity and gypsum bearing rocks, as well as high groundwater salinity of the cone delta zone are the source of modern salt accumulation in soils of foothill Golodnostepskaya plain, as well as in soils of the cone delta zone of Djizak steppe.

Obtaining Calcium Sulfoaluminate Using Aluminate Waste

In this work, studies have been carried out to replace bauxite with aluminate slags. Compounds of raw mixtures without use of fossil aluminate materials with different gypsum content have been developed. Instability of assimilation of anhydrite into calcium sulphoaluminate has been established. X-ray phase analysis has shown a weak dependence of increase in the firing temperature and increase in the yield of the main mineral C3A3·CŜ. Results of the study allow us to conclude that it is possible to obtain high-quality calcium sulphoaluminate (SAC) based on technogenic aluminate raw material.

The Effect Of Gypsum Content And Seasonal Variations On The Enzyme Activity And Respiration Properties Of Heavy Soils In Reclamation Status

This article discusses the effect of gypsum content and seasonal variations on the enzyme activity and respiration properties of bad melioration content of soil in Uzbekistan. Furthermore, this paper provides some datas about their origins and how to eliminate it.