Electric self-curing steel slag-based ultra-high performance concrete and preparation method thereof

Abstract

The invention provides electric self-curing steel slag-based ultra-high performance concrete and a preparation method thereof, and belongs to the technical field of building materials. The main components comprise cement, silica fume, mineral powder, steel slag, water, a water reducing agent, regenerated polyethylene particles and regenerated carbon fibers; the concrete is prepared from the following components in parts by weight: 900 to 1000 parts of cement, 50 to 100 parts of silica fume, 100 to 150 parts of mineral powder, 900 to 1200 parts of steel slag, 100 to 200 parts of water, 15 to 20 parts of a water reducing agent, 100 to 120 parts of regenerated polyethylene particles and 10 to 20 parts of regenerated carbon fibers. The mixing amount of the fibers is 1%-3% of the total volume of the fiber concrete. Through practical application of fibers, the invention provides a solution that high tensile strength, high compressive strength and high ductility of concrete in the prior art are difficult to coexist in alpine regions or emergency rescue.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an electro-curing steel slag-based ultra-high performance concrete and its preparation method. Background Technology

[0002] Concrete is the most widely used foundational material in civil engineering. Its low cost, readily available raw materials, and mature manufacturing process have led to its extensive use in the construction of various infrastructure projects, including buildings, roads, and bridges. However, traditional concrete is inherently a brittle material with low tensile strength and poor deformation capacity. Under external loads and temperature stresses, it is highly susceptible to the formation and propagation of microcracks, leading to structural spalling, damage, and even failure, severely impacting the durability and safety of the structure.

[0003] This problem is particularly prominent in rigid pavement engineering projects operating in cold, high-altitude, and heavily loaded environments. On the one hand, the frigid environment slows down or even halts the hydration reaction of concrete, severely hindering early strength development, and freeze-thaw cycles exacerbate damage to the internal structure. On the other hand, under the repeated impact of heavy vehicle loads over long periods, pavement is prone to developing initial micro-cracks. These cracks expand and connect under the coupled effect of frigidity and load, eventually leading to pavement surface erosion, uneven subsidence, and other defects. Even more serious is the fact that the harsh climate and traffic conditions in cold regions make routine maintenance and repair work exceptionally difficult and costly, often resulting in untreated defects and a vicious cycle.

[0004] Therefore, existing technologies face a key contradiction in harsh, cold environments: the properties of traditional concrete materials (high brittleness and difficulty in curing at low temperatures) cannot meet the high standards of structural durability, long lifespan, and ease of maintenance required by demanding service environments. The market urgently needs an innovative concrete preparation and curing technology that not only endows concrete with excellent mechanical properties to resist heavy loads and low-temperature stresses, but also possesses efficient, adaptive, and environmentally insensitive curing characteristics to ensure rapid and full strength development even under frigid conditions, thereby fundamentally improving the service performance and lifespan of structures in extreme environments. Summary of the Invention

[0005] The purpose of this invention is to provide an electro-curing steel slag-based ultra-high performance concrete and its preparation method, which strengthens the steel slag-based concrete by mixing recycled carbon fiber and recycled polyethylene particles, thereby enabling it to possess electro-curing and ultra-high performance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an electro-curing steel slag-based ultra-high performance concrete, wherein the components of the ultra-high performance concrete and the proportions of each component by mass are as follows:

[0007] 900-1000 parts cement

[0008] 50-100 parts silica fume

[0009] 100-150 parts of mineral powder

[0010] 900-1200 parts of steel slag

[0011] 100-200 parts water

[0012] 15-20 parts of water-reducing agent

[0013] 100-120 parts recycled polyethylene granules

[0014] 10-20 parts recycled carbon fiber

[0015] Furthermore, the cement used is P·O52.5 grade ordinary Portland cement with a fineness of 800-900 mesh.

[0016] Furthermore, the fineness modulus of the steel slag is 1.5-0.7, and the water-reducing agent is a high-performance pure water-reducing agent of polycarboxylate, with a dosage of 0.5%-1% of the total mass of the cementitious material.

[0017] Furthermore, the recycled polyethylene particles have a diameter of 2.5 mm and a length of 5-6 mm, and the recycled carbon fibers have a diameter of 0.007 mm and a length of 6-10 mm.

[0018] Furthermore, the recycled carbon fiber is pre-dispersed with 10-20 parts of hydroxyethyl methyl cellulose.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) This invention constructs a multi-scale spatial network structure in a concrete matrix by mixing and adding recycled carbon fibers and recycled polyethylene particles of different lengths. This design effectively optimizes the damage evolution mechanism of concrete, thereby effectively suppressing crack propagation during stress.

[0021] (2) The present invention enables concrete to generate uniform ohmic heat after being energized by a three-dimensional conductive network formed by recycled carbon fibers. This characteristic gives the concrete the ability to self-curing, and it can achieve rapid strength development in low-temperature environments without the need for external heat sources or complex insulation measures.

[0022] (3) By using hydroxyethyl cellulose to pre-disperse the fibers, the present invention effectively reduces the tendency of fiber agglomeration, ensures the uniform dispersion of various fibers in concrete paste, and enables the fiber reinforcement effect to be fully exerted. Attached Figure Description

[0023] Figure 1 Pore ​​distribution diagrams for 20V electrical curing and standard curing. Detailed Implementation

[0024] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] A method for preparing electro-curing steel slag-based ultra-high performance concrete includes the following steps:

[0027] Step 1: Pre-dispersion of recycled carbon fiber

[0028] (1) Weigh out hydroxyethyl cellulose and dissolve it completely in water.

[0029] (2) Weigh the recycled carbon fiber and put it into the solution in step (1). Use an ultrasonic disperser and mechanical stirring for 2-4 hours to disperse the fiber evenly.

[0030] (3) The uniformly dispersed fiber solution is filtered, rinsed and dried to obtain fibers with good dispersibility.

[0031] Step 2: Preparation of Electro-cured Steel Slag-based Ultra-high Performance Concrete

[0032] (1) Weigh cement, silica fume, mineral powder, steel slag and water-reducing agent and put them into a mixer and stir for 2-3 minutes until the materials are evenly mixed to obtain mixed dry material.

[0033] (2) Weigh out water and add it to the mixed dry materials at once, stir for 2-4 minutes to obtain a uniform slurry.

[0034] (3) Slowly add the pre-dispersed recycled carbon fiber and recycled polyethylene particles into the slurry and stir for 4-6 minutes to obtain electro-curing steel slag-based ultra-high performance concrete.

[0035] Example 1

[0036] First, the electro-curing steel slag-based ultra-high performance concrete mixture was poured into an electro-curing mold, vibrated on a vibrating table for 5 minutes, covered with plastic wrap for 1 hour of pre-curing, and then directly electro-cured at 20V for 8 hours. After 3 days of curing, the mechanical properties and mercury porosimetry of the sample prepared in this embodiment were tested in accordance with the "Test Methods for Mechanical Properties of Ordinary Concrete" (GB / T50081-2019).

[0037] Comparative Example 1

[0038] Unlike Example 1, no recycled carbon fiber and recycled polyethylene particles were added to the material formulation, and no electric curing was used. After curing under standard curing conditions for 3 days, the mechanical properties and mercury intrusion porosimetry of the samples prepared in this comparative example were tested according to the "Test Methods for Mechanical Properties of Ordinary Concrete" (GB / T50081-2019).

[0039] Figure 1 The diagram shows the pore distribution under 20V electric curing and standard curing. The pore structure of electro-cured concrete mainly consists of gel pores and transition pores with a diameter of less than 100 nanometers, while harmful pores larger than 100 nanometers are extremely rare. This is because charged cement particles and unhydrated particles undergo electrophoretic movement under the action of an electric field, promoting particle rearrangement and forming a denser packing structure, effectively reducing large voids caused by uneven particle packing.

[0040] In contrast, traditional cured concrete exhibits a bimodal pore distribution, with its pore size concentrated below 10 nanometers and in the range of 50 to 1200 nanometers. The presence of capillaries has a significant impact on the strength of concrete.

[0041] Table 1 shows the mechanical test results of Example 1 and Comparative Example 1. The results show that the mechanical properties of the concrete of the present invention are significantly improved after electro-curing.

[0042]

[0043] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An electro-curing steel slag-based ultra-high performance concrete, characterized in that: The components and proportions of each component in the electro-curing steel slag-based ultra-high performance concrete, by weight, are as follows: 900-1000 parts cement 50-100 parts silica fume 100-150 parts of mineral powder 900-1200 parts of steel slag 100-200 parts water 15-20 parts of water-reducing agent 100-120 parts recycled polyethylene granules 10-20 parts of recycled carbon fiber.

2. The electro-curing steel slag-based ultra-high performance concrete according to claim 1, characterized in that: The cement used is P·O52.5 grade ordinary Portland cement with a fineness of 800-900 mesh.

3. The electro-curing steel slag-based ultra-high performance concrete according to claim 1, characterized in that: The fineness modulus of the steel slag is 1.5-0.7, and the water-reducing agent is a high-performance pure water-reducing agent of polycarboxylate, with a dosage of 0.5%-1% of the total mass of the cementitious material.

4. The electro-curing steel slag-based ultra-high performance concrete according to claim 1, characterized in that: The recycled polyethylene particles have a diameter of 2.5 mm and a length of 5-6 mm, and the recycled carbon fibers have a diameter of 0.007 mm and a length of 6-10 mm.

5. The electro-curing steel slag-based ultra-high performance concrete according to claim 1, characterized in that: The recycled carbon fiber is pre-dispersed with 10-20 parts of hydroxyethyl methyl cellulose.

6. The method for preparing electro-curing steel slag-based ultra-high performance concrete according to claim 1, characterized in that: Includes the following steps: Step 1: Pre-dispersion of recycled carbon fiber; (1) Weigh out hydroxyethyl cellulose and dissolve it completely in water. (2) Weigh the recycled carbon fiber and put it into the solution in step (1). Use an ultrasonic disperser and mechanical stirring for 2-4 hours to disperse the fiber evenly. (3) The uniformly dispersed fiber solution is filtered, rinsed and dried to obtain fibers with good dispersibility. Step 2: Preparation of electro-cured steel slag-based ultra-high performance concrete; (1) Weigh cement, silica fume, mineral powder, steel slag and water-reducing agent and put them into a mixer and stir for 2-3 minutes until the materials are evenly mixed to obtain mixed dry material. (2) Weigh out water and add it to the mixed dry materials at once, stir for 2-4 minutes to obtain a uniform slurry. (3) Slowly add the pre-dispersed recycled carbon fiber and recycled polyethylene particles into the slurry and stir for 4-6 minutes to obtain electro-curing steel slag-based ultra-high performance concrete.

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