Composite ferronickel slag powder cement soil as well as preparation method and application thereof

Abstract

The invention provides composite ferronickel slag powder cement soil as well as a preparation method and application thereof. The composite ferronickel slag powder cement soil is prepared from cement, blast furnace ferronickel slag powder, silica fume, water, clay and a water reducing agent according to a certain proportion. The blast furnace ferronickel slag powder is a material with low activity in the early stage, but can improve the durability of the cement soil in seawater in the later stage. The blast furnace ferronickel slag powder is adopted to replace part of cement, slag accumulation can be further reduced, the influence on the environment is reduced, a bulk material source is provided for cement and concrete, and the cement can be used as a novel mineral admixture. The added silica fume can relieve the negative influence caused by insufficient early-stage activity of the blast furnace ferronickel slag powder. The blast furnace ferronickel slag powder and the silica fume in a certain proportion are adopted as the composite mineral admixture to replace part of cement, and the unconfined compressive strength of the ferronickel slag powder cement soil can be improved. Moreover, the preparation method is simple and easy to operate, the mechanical property of the prepared composite ferronickel slag powder cement soil is improved, and the composite ferronickel slag powder cement soil can be well applied to constructional engineering.

Description

Technical Field

[0001] The invention relates to the technical field of new building materials, and more specifically to composite nickel-iron slag powder cement soil and a preparation method and application thereof. Background Art

[0002] With the development of the Guangdong-Hong Kong-Macao Greater Bay Area, a large number of projects will be built on reinforced soft soil foundations along the coast in the future. The corrosive ions in the seawater will deteriorate the cement soil, and it is necessary to alleviate the degradation caused by seawater by adding mineral admixtures. At present, the consumption of concrete in my country is increasing year by year. As high-quality mineral admixtures are an indispensable part of concrete, the increase in concrete consumption will inevitably lead to an increase in the consumption of high-quality mineral admixtures. Therefore, it is urgent to find new mineral admixtures. Blast furnace nickel-iron slag powder is a new type of mineral admixture with low initial activity. The use of blast furnace nickel-iron slag powder and silica fume to prepare a composite nickel-iron slag admixture can not only improve the mechanical properties of cement soil, but also provide a bulk material source for cement and concrete, reducing slag accumulation.

[0003] At present, it has been found through experiments that the mechanical properties of cement soil mixed with blast furnace nickel-iron slag powder alone will gradually decrease with the increase of blast furnace nickel-iron slag powder content, which is consistent with the results of most literature studies that the early activity of blast furnace nickel-iron slag powder is low. Therefore, the early mechanical properties of blast furnace nickel-iron slag powder cement soil are poor, which limits its practical application. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of poor unconfined compressive strength in the existing preparation of cement soil using blast furnace nickel-iron slag powder, and to provide a composite nickel-iron slag powder cement soil. By adding a certain proportion of blast furnace nickel-iron slag powder and silica fume and adjusting the proportions of the various components of the cement soil, the composite nickel-iron slag powder cement soil with improved unconfined compressive strength and good durability is obtained.

[0005] Another object of the present invention is to provide a method for preparing composite nickel-iron slag powder cement soil.

[0006] Another object of the present invention is to provide an application of composite nickel-iron slag powder cement soil.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A composite nickel-iron slag powder cement soil is prepared by adopting a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.254-0.363: 1.602: 0-0.109: 0-0.016: 0.006.

[0009] The present invention adopts a certain ratio of blast furnace nickel-iron slag powder and silica fume as mineral admixtures to replace part of cement, and silica fume promotes cement hydration reaction and silica fume undergoes secondary volcanic ash reaction to generate hydrated calcium silicate gel to wrap the surface of soil particles, and the number of particles that do not undergo hydration reaction is reduced. The gel constructs a "network-like" spatial skeleton with soil particles, blast furnace nickel-iron slag particles and small silicon balls to fill between large soil particles, further improving the compactness and strength of cement soil. Further adjusting the ratio of other components of the mineral admixture, thereby improving the performance of cement soil after hardening, and having a significant improvement effect on durability. At the same time, the unreacted blast furnace nickel-iron slag powder and silica fume can be filled in the pores of cement and aggregate, reducing the porosity of cement soil, making the interior of cement soil more compact, and improving the unconfined compressive strength of cement soil.

[0010] Preferably, the water-cement ratio is 0.5, the cement addition ratio is 15%, and the mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent is 1: 0.254-0.363: 1.602: 0-0.109: 0-0.016: 0.006.

[0011] Preferably, the clay is continuously graded clay with a particle size of less than or equal to 5.00 mm.

[0012] Preferably, the blast furnace nickel-iron slag powder is a homemade mineral admixture with a particle size of less than or equal to 0.075 mm.

[0013] Preferably, the blast furnace nickel-iron slag powder is provided by Dadi Environmental Protection Building Materials Co., Ltd., Yangjiang City, Guangdong Province.

[0014] Preferably, the water reducer is a QL-5 type high efficiency water reducer.

[0015] The method for preparing the composite nickel-iron slag powder cement soil of the present invention comprises the following steps:

[0016] First, silica fume and blast furnace nickel-iron slag powder are fully mixed to form composite nickel-iron slag powder; the composite nickel-iron slag powder is poured into cement and fully mixed; clay and the prepared cement are poured into a mixer in batches and mixed for 5 to 10 minutes to obtain a mixture; finally, water and a water reducing agent are added to the mixture to obtain composite nickel-iron slag powder cement soil.

[0017] Preferably, the preparation method further comprises pouring the composite nickel-iron slag powder cement soil into a mold and curing and forming it.

[0018] Specifically, after pouring into the mold, the process also includes watering the mold around and covering its surface with a plastic film, and continuing to water during the curing period until it is cured and formed.

[0019] The invention also protects the application of the composite nickel-iron slag powder cement soil in construction engineering.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The composite nickel-iron slag powder cement soil provided by the present invention improves the unconfined compressive strength of the composite nickel-iron slag powder cement soil by replacing part of cement with blast furnace nickel-iron slag powder and silica fume in a certain ratio. The blast furnace nickel-iron slag powder can fully reduce slag accumulation and reduce the impact on the environment. In addition, the preparation method of the present invention is simple and easy to operate. The durability and mechanical properties of the prepared composite nickel-iron slag powder cement soil are improved, and the composite nickel-iron slag powder cement soil can be better applied to construction projects. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0023] Materials used in the examples and comparative examples:

[0024] Cement: The brand is ordinary silicate 42.5R cement, purchased from Guangzhou Shijing Cement Company.

[0025] Blast furnace nickel-iron slag powder: provided by Yangjiang Dadi Environmental Protection Building Materials Co., Ltd., Guangdong Province.

[0026] Silica fume: also known as microsilica powder, purchased from Henan Yuanheng Environmental Protection Engineering Co., Ltd.

[0027] Water reducing agent: QL-5 high efficiency water reducing agent, purchased from Jiangmen Qiangli Construction Technology Co., Ltd.

[0028] Clean water: taken from tap water in Guangzhou.

[0029] Clay: Taken from the vacant land of Dajisha Island, Huangpu District, Guangzhou.

[0030] Example 1

[0031] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.363: 1.602: 0: 0: 0.006.

[0032] The preparation method of the composite nickel-iron slag powder cement soil comprises the following steps:

[0033] Clean the test mold and apply a thin layer of mold release oil on its inner wall to facilitate demoulding; clean and soak the mixer; pour the clay and the prepared cement into the mixer in batches and stir evenly for 5 to 10 minutes to obtain a mixture; finally, add water and a water reducing agent to the mixture and stir for 5 to 10 minutes to obtain a composite nickel-iron slag powder cement soil.

[0034] Example 2

[0035] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.055: 0: 0.006.

[0036] The preparation method of the composite nickel-iron slag powder cement soil comprises the following steps:

[0037] Clean the test mold and apply a thin layer of mold release oil on its inner wall to facilitate demoulding; clean and soak the mixer; pour the blast furnace nickel-iron slag powder into the cement and stir it thoroughly; then pour the clay and the prepared cement into the mixer in batches and stir them evenly for 5 to 10 minutes to obtain a mixture; finally, add water and a water reducing agent into the mixture and stir it for 5 to 10 minutes to obtain a composite nickel-iron slag powder cement soil.

[0038] Comparative Example 1

[0039] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.055: 0: 0.006.

[0040] The preparation method of the above-mentioned composite nickel-iron slag powder cement soil is the same as that in Example 2.

[0041] Comparative Example 2

[0042] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.254: 1.602: 0.109: 0: 0.006.

[0043] The preparation method of the above-mentioned composite nickel-iron slag powder cement soil is the same as that in Example 2.

[0044] Comparative Example 3

[0045] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.052: 0.003: 0.006.

[0046] The preparation method of the composite nickel-iron slag powder cement soil comprises the following steps:

[0047] Clean the test mold and apply a thin layer of mold release oil on its inner wall to facilitate demoulding; clean and soak the mixer; first pour silica fume into blast furnace nickel-iron slag powder and stir it thoroughly, then pour the composite nickel-iron slag powder into cement and stir it thoroughly, then pour clay and prepared cement into the mixer in batches and stir for 5 to 10 minutes to obtain a mixture; finally, add water and water reducing agent into the mixture and stir for 5 to 10 minutes to obtain composite nickel-iron slag powder cement soil.

[0048] Comparative Example 4

[0049] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.049: 0.006: 0.006.

[0050] The preparation method of the above-mentioned composite nickel-iron slag powder cement soil is the same as that of Comparative Example 3.

[0051] Comparative Example 5

[0052] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.046: 0.008: 0.006.

[0053] The preparation method of the above-mentioned composite nickel-iron slag powder cement soil is the same as that of Comparative Example 3.

[0054] Comparative Example 6

[0055] A composite nickel-iron slag powder cement soil comprises a water-cement ratio of 0.5, a cement mixing ratio of 15%, and a mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent of 1: 0.309: 1.602: 0.038: 0.016: 0.006.

[0056] The preparation method of the above-mentioned composite nickel-iron slag powder cement soil is the same as that of Comparative Example 3.

[0057] Performance Testing

[0058] 1. Test methods

[0059] The cement soil prepared in the embodiment and the comparative example was put into a mold; then it was placed on a vibrating table and vibrated evenly; after being vibrated into shape, the specimen was placed in an indoor environment for natural curing, water was poured around the mold, and its surface was covered with a waterproof plastic film; after standing for 48 hours, the mold was removed, and the specimen was continued to be placed in clean water at room temperature for curing for 28 days, with the liquid level exceeding the specimen by 3 cm.

[0060] Unconfined compressive strength test: YAW-50D microcomputer-controlled constant pressure testing machine produced by Times New Technology, with a loading rate of 0.1kN / s.

[0061] 2. Test results

[0062] Table 1 Performance test results of composite nickel-iron slag powder cement soil specimens of the embodiments and comparative examples

[0063] Serial number Unconfined compressive strength (MPa) Mechanical properties Example 1 1.82 good Example 2 1.69 good Comparative Example 1 1.69 good Comparative Example 2 1.57 good Comparative Example 3 1.72 good Comparative Example 4 1.77 good Comparative Example 5 1.72 good Comparative Example 6 1.63 good

[0064] It can be seen from the results in Table 1 that the unconfined compressive strength of the composite nickel-iron slag powder cement soil obtained in Comparative Examples 1 to 2 is somewhat lower than that in Example 1. This is obviously due to the low initial activity of the blast furnace nickel-iron slag powder, which is mainly filled in the pores of the cement soil in the form of micro-aggregates and cannot generate more substances with good cementitious properties. The unconfined compressive strength of the composite nickel-iron slag powder cement soil obtained in Comparative Examples 3 to 5 is improved to a certain extent compared with Example 2, which is attributed to the silica fume promoting the cement hydration reaction and the silica fume undergoing a secondary volcanic ash reaction to generate hydrated calcium silicate gel to wrap the surface of the soil particles, and the number of particles that have not undergone hydration reaction is reduced. The gel constructs a "network-like" spatial skeleton with soil particles, blast furnace nickel-iron slag powder particles and small silicon balls to fill in between large soil particles, further improving the density and strength of the cement soil. The unconfined compressive strength of the composite nickel-iron slag powder cement soil obtained in Comparative Example 6 is lower than that in Example 2 to a certain extent, which is attributed to the fact that excessive silica fume consumes a large amount of calcium hydroxide, affecting the secondary volcanic ash reaction of part of the silica fume, and the silica fume that does not participate in the secondary volcanic ash reaction increases, weakening the bonding between soil particles; at the same time, it also affects the hydration reaction of blast furnace nickel-iron slag powder. From the above results, it can be seen that the present invention has a certain enhancement effect on the unconfined compressive strength of the composite nickel-iron slag powder cement soil by adding an appropriate amount of silica fume.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A composite nickel-iron slag powder cement soil, characterized in that: The water-cement ratio is 0.5, the cement mixing ratio is 15%, and the mass ratio of water: cement: clay: blast furnace nickel-iron slag powder: silica fume: water reducing agent is 1: 0.254-0.363: 1.602: 0-0.109: 0-0.016: 0.

006.

2. The composite nickel-iron slag powder cement soil according to claim 1, characterized in that: The clay is selected from Dajisha Island, Huangpu District, Guangzhou City, with a natural moisture content of 51.2% and a density of 1.79 kg / m 3 .

3. The composite nickel-iron slag powder cement soil according to claim 1, characterized in that: The clay has a particle size of less than or equal to 5 mm.

4. The composite nickel-iron slag powder cement soil according to claim 1, characterized in that: The blast furnace nickel-iron slag powder is provided by Dadi Environmental Protection Building Materials Co., Ltd., Yangjiang City, Guangdong Province.

5. The composite nickel-iron slag powder cement soil according to claim 1, characterized in that: The particle size of the blast furnace nickel-iron slag powder is less than or equal to 0.075 mm.

6. The method for preparing composite nickel-iron slag powder cement soil according to any one of claims 1 to 5, characterized in that: The steps include: First, silica fume and blast furnace nickel-iron slag powder are fully mixed to form composite nickel-iron slag powder; the composite nickel-iron slag powder is poured into cement and fully mixed; clay and the prepared cement are poured into a mixer in batches and mixed for 5 to 10 minutes to obtain a mixture; finally, water and a water reducing agent are added to the mixture, and the mixture is mixed for 5 to 10 minutes to obtain composite nickel-iron slag powder cement soil.

7. The preparation method according to claim 6, characterized in that: The preparation method further comprises pouring the composite nickel-iron slag powder cement soil into a mold and curing and forming it.

8. Use of the composite nickel-iron slag powder cement soil as claimed in any one of claims 1 to 5 in construction projects.