Specimen Preparation. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute shrinkage rate versus compaction. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Sample preparation process diagram. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Dry wet cycle process. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute expansion rate fitting results. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute expansion rate fitting results. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute shrinkage rate fitting results. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Basic parameters of cement. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Basic Parameters of Phosphogypsum. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Image processing process. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute expansion rate versus compaction. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Chemical Composition of Phosphogypsum. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Fracture ratio versus cement dosage. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute shrinkage rate versus cement dosage. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute expansion rate versus cement dosage. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Fracture ratio versus initial water content. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Fracture ratio versus compaction degree. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Absolute shrinkage rate fitting results. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Schematic diagram of the wet/dry cycle process. by Liangchun Xu (21781958)

“…The test results showed that, firstly, the absolute expansion and absolute shrinkage of cement-stabilized phosphogypsum materials increased with the increase of compaction, cement dosage and the number of wet and dry cycles, and decreased with the increase of initial water content and the dosage of phosphogypsum; Secondly, the fracture rate of cement-stabilized phosphogypsum materials increased with cement dosage and the number of wet and dry cycles; and decreased with compaction, initial moisture content, and phosphogypsum dosage; Thirdly, the relationship between the absolute expansion or shrinkage of cement-stabilized phosphogypsum materials and the compaction degree and the fracture rate is not a simple linear relationship, but is affected by a combination of factors, showing nonlinear characteristics, which can be fitted by the nonlinear binary quadratic equation f(x,y) =ax²+bx+cy²+dy+e. …”

Cohesion experiment videos by Nacere Mohamed Samassi (21395537)

“…With increasing cohesion, we observe a transition from highly mobile, braided to single thread meandering channels, then to straight, gully-like channels with headcuts that exhibit decreasing distance of retreat with increasing cohesion. …”