CN-121997580-A - Clinker-free ecological cement mix proportion design method based on particle closest packing theory

CN121997580ACN 121997580 ACN121997580 ACN 121997580ACN-121997580-A

Abstract

The invention discloses a clinker-free ecological cement mixing proportion design method based on the particle closest packing theory. And extracting powder fractal characteristics based on a fractal theory through particle size distribution and specific surface area tests, and mapping the powder fractal characteristics to a Dinger-Funk model to construct theoretical optimal particle size cumulative distribution. And then weighting and superposing the actual particle size distribution of each raw material according to the mass ratio to form the actual cumulative distribution of the mixed system, and further establishing a deviation function between the two. And (3) establishing an optimization model with constraint by introducing Lagrangian multipliers, and automatically obtaining the optimal mass proportion of the raw materials by using a numerical method, so that the grain composition of the mixed system is closer to the closest packing state. The clinker-free ecological cement test piece prepared according to the optimization result has good stacking property and mechanical property. The invention realizes parameterization, quantification and automation of clinker-free cement proportioning design, can adapt to industrial solid waste raw materials of different batches, and has good engineering application value.

Inventors

CHENG ZHI
WANG HUI
YAN YUTING
LI GUANGRUI
LI JIANGBO
YIN CHUANFENG
XUE JUN
XI RUI
LI DONGSHENG
Mu Chuanchuan
GUO KAIWEN
QIAO HUA

Assignees

山西省智慧交通实验室有限公司
中北大学
山西路桥再生资源开发有限公司
山西路桥第八工程有限公司

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (10)

1. S1, respectively carrying out laser particle size meter test on ground CFB slag, CFB fly ash, mineral powder, silica fume and desulfurized gypsum to obtain particle size distribution and specific surface area data, and determining the minimum particle size of a mixed system according to the particle size distribution And maximum particle size ; S2, constructing a log (V) -log (S) scatter diagram of the particle size volume and the specific surface area of the raw material based on a fractal theory, obtaining a slope calculation particle fractal dimension through linear fitting, and obtaining a particle size distribution coefficient q of Dinger-Funk equation according to the fractal dimension to form theoretical optimal particle size cumulative distribution; s3, weighting and superposing the accumulated volume fractions of the raw materials at different particle diameters according to the mass ratio of the raw materials to form actual accumulated volume distribution of the mixed system, and constructing a deviation function between theoretical optimal distribution and actual distribution; S4, under the condition that the sum of the mass fractions of the raw materials is 1, a Lagrange parameter is introduced to establish a constraint optimization model, and particle size distribution data, the minimum particle size, the maximum particle size and a distribution coefficient q of each raw material are introduced into MATLAB, and the mass fractions of the raw materials with the minimum deviation are obtained through numerical solution; s5, preparing a clinker-free ecological cement test piece according to the proportion of the obtained raw materials, testing the stacking compactness and the 28d compressive strength of the clinker-free ecological cement test piece, judging that the clinker-free ecological cement test piece reaches the standard when the stacking compactness is not lower than 0.75 and the 28d compressive strength is not lower than 42.5MPa, otherwise, returning to the step S3, adjusting parameters and re-optimizing.
2. The method according to claim 1, wherein the laser particle analyzer has a test range of 0.1-500 μm, the particle size distribution is recorded in a particle size interval Di and a corresponding cumulative volume fraction, and the specific surface area is measured by using a bosch ventilation method, and the measurement accuracy is + -0.1 m2/kg.
3. The method of claim 1, wherein the theoretical optimum particle size cumulative distribution of S2 is calculated using the equation Dinger-Funk, expressed as: ; Wherein the method comprises the steps of As theoretical optimal cumulative volume fraction Is made into the particle size of the powder, Is the particle size of the particles which is the smallest, And q is the particle size distribution coefficient.
4. The method of claim 1, wherein the bias function of S3 is constructed using a least squares method, expressed as: ; wherein E is a distribution deviation value, Is the number of the particle size intervals, Is the mass ratio of the j-th raw material, In particle size for the j-th material Cumulative volume fraction at.
5. The method according to claim 1, wherein the constrained optimization model of S4 constructs its objective function by introducing lagrangian parameters as: ; Constraint of 0< > <1 And 。
6. The method according to claim 1, wherein the MATLAB numerical solution of S4 includes a step of cumulatively distributing particle diameters of the respective raw materials Particle size Minimum particle diameter Maximum particle size And the distribution coefficient q is imported into a MATLAB working area, lagrange objective functions are defined based on the deviation function and the constraint condition, and the objective function pairs are solved respectively 、、、、 And constructing a multi-element equation set by adding the partial derivative and making the partial derivative equal to 0, and obtaining the optimal raw material mass ratio by adopting a Newton-Laportson iteration method.
7. The method according to claim 6, wherein the convergence accuracy of the newton-raphson method is set to be And by As an initial iteration value.
8. The method according to claim 1, characterized in that the actual cumulative volume distribution of the mixed system is obtained by: ; Wherein Umix (Di) is the particle size of the mixed system Cumulative volume fraction at.
9. The method according to claim 1, wherein the packing density test is performed by a drainage method and the mechanical property test is performed according to the GB/T17671-2021 standard.
10. The method according to claim 1, wherein when the stacking compactness of the test piece is lower than 0.75 or the 28d compressive strength is lower than 42.5MPa, the optimal solution is carried out again by adjusting the distribution coefficient q, the iteration initial value or the iteration step length so as to obtain the optimal raw material quality ratio meeting the performance requirement.

Description

Clinker-free ecological cement mix proportion design method based on particle closest packing theory Technical Field The invention relates to the technical field of building materials and solid waste resource utilization, in particular to a clinker-free ecological cement mixing proportion design method based on a particle closest packing theory. Background The clinker-free ecological cement takes industrial solid waste as a main raw material, does not need a high-temperature calcination process, can obviously reduce carbon emission and energy consumption, and is an important direction of converting building materials into green and low-carbonization. The pulverized CFB slag and CFB fly ash are used as typical solid waste generated by a circulating fluidized bed coal-fired unit, and have the characteristics of huge yield, stable components, capability of developing activity potential and the like, and the mineral powder, the silica fume and the desulfurized gypsum are used as byproducts of the steel industry and a flue gas desulfurization device, and also have the advantages of large scale and stable sources. The five industrial solid wastes are cooperatively used for preparing clinker-free ecological cement, so that the use of traditional silicate clinker is reduced, the carbon emission pressure is relieved, the environmental problems of occupation of the industrial solid waste stockpile, secondary dust emission, leachate pollution and the like can be effectively solved, and the clinker-free ecological cement has remarkable comprehensive benefits of resources, environment and economy. However, the mix proportion design of the clinker-free ecological cement at present still stays in the stages of experience trial, single factor test or simple orthogonal test mostly, and lacks scientific and systematic powder grading analysis and mathematical modeling support. Because the particle size difference of the ground CFB slag, the CFB fly ash, the mineral powder, the silica fume and the desulfurized gypsum is large, the particle morphology difference is obvious, part of raw materials are in multimodal particle size distribution, and part of raw materials are irregular in particle shape, the random proportion often causes loose particle stacking structure, high porosity and insufficient void filling. The large number of communicating pores in the powder system not only affects the compactness, but also causes the problems of insufficient structural strength, higher water consumption, increased shrinkage and the like of the hardened cement, and limits the popularization and the use of clinker-free ecological cement in the field of structural engineering. In addition, the property difference of solid wastes of different sources and different batches is large, and a repeatable and movable proportioning system is difficult to establish by a traditional experience method, so that the product has large performance fluctuation and insufficient stability, and the engineering application reliability is further influenced. The particle closest packing theory is an important basic theory in the field of powder material design, and the proportion of particles with different particle diameters can be reasonably controlled to minimize the inter-particle gaps, so that the packing density of the material is improved, and the porosity is reduced. The Dinger-Funk equation is used as a classical mathematical model of the closest packing state in a continuous size grading system, is applied to material systems such as ceramic powder, dry-mixed mortar, ultra-high performance concrete and the like, and can be used for guiding the optimal construction of particle distribution. However, the application of the theory in clinker-free ecological cement systems is still less, on one hand, the solid waste particles are complex in appearance and large in particle size span, the traditional grading model is difficult to directly reflect the real characteristics of the solid waste particles, and on the other hand, the traditional research usually adopts a single index (such as average particle size) for rough control, and a complete powder grading-performance relationship cannot be established. Meanwhile, the proportioning design process involves multiple raw materials, multiple constraints and multi-objective optimization, and the raw material proportion with global optimality is difficult to obtain by means of manual experiments or univariate analysis alone. The Lagrangian parameter method is an effective mathematical tool for solving the constraint optimization problem, can realize deviation minimization solution on the premise of guaranteeing the proportion sum of raw materials to be 1, and can greatly improve the optimization efficiency by combining a numerical calculation platform. However, in the published literature and the prior engineering practice, the particle closest packing theory, dinger-Funk model and Lagrange parameter method are n