A method for preparing underwater micro / nano cementitious materials

Abstract

This invention discloses a method for preparing underwater micro / nano cementitious materials. The method includes the following steps: Step 1, modifying iron-containing solid waste with a powder material containing hydraulic cementitious materials and a magnetic supplementary material to form a magnetic agglomerate; Step 2, further modifying the magnetic agglomerate with supplementary micro / nano powder materials to form the underwater micro / nano cementitious material. The micro / nano gel material prepared by this invention can be formed before hydration and can naturally hydrate and harden underwater without the use of molds, solving the problem that cement powder particles are difficult to form underwater due to dispersion.

Description

Technical Field

[0001] This invention relates to a method for preparing a cementitious material, specifically a method for preparing an underwater micro / nano cementitious material. Background Technology

[0002] Concrete is the most widely used engineering material, and its gelation effect is mainly produced by the hydration of cement. The construction of underwater civil engineering structures requires complex processes to hydrate and shape the concrete underwater. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing underwater micro-nano cementitious materials. The micro-nano cementitious materials prepared by this method can hydrate and form cement-based materials underwater, solving the problem that cement powder particles are difficult to form when dispersed underwater.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for preparing an underwater micro / nano cementitious material includes the following steps:

[0006] Step 1: Modify iron-containing solid waste using powdered materials containing hydraulic cementitious materials and magnetic additives to form magnetic aggregates, wherein:

[0007] The powder material containing the hydraulic gel material is composed of cement and nanoporous materials;

[0008] The cement is aluminate cement, with a residue of ≤10% on a 30μm sieve.

[0009] The nanoporous material is one or more of nanoporous materials such as nano-biochar and nano-zeolite, and the dosage is 0.3% to 0.9% of the mass of aluminate cement.

[0010] The nano-biochar has a particle size of 200-300 nm and a pore volume of 0.04-0.08 cm³. 3 / g, with a dosage of 0.6~0.9% of the mass of aluminate cement;

[0011] The nano-zeolite has a particle size of 120~180nm and a pore volume of 0.65~0.85cm³. 3 / g, with a dosage of 0.3%~0.6% of the mass of aluminate cement;

[0012] The iron-containing solid waste has an iron content of 8-18%, a residue of ≤10% on a 35μm sieve, and is added at a dosage of 30-50% of the mass of aluminate cement.

[0013] The magnetic supplementary material is a nano-magnetic material with a particle size of 30~100nm, and the dosage is 5~10% of the iron-containing solid waste material.

[0014] The modification method employs ball milling modification. Zirconia balls with an equal particle diameter of 3-5 mm are selected for milling. The milling time is 120-240 minutes, the revolution speed of the milling jar is 150-180 rpm, the rotation speed is 300-350 rpm, the ball-to-material volume ratio is 2:1.1, and the ball-to-material volume ratio of the milling jar is 4:5. After ball milling modification, magnetic agglomerates are selected using magnetic screening.

[0015] Step 2: The magnetic agglomerate is further modified with supplementary micro / nano powder materials to form an underwater micro / nano cementitious material, wherein:

[0016] The supplementary micro / nano powder material is composed of cement, nano-silica, etc.

[0017] The cement is ordinary Portland cement, with a residue of ≤10% on a 30μm sieve, and its admixture is 10~30% of the mass of aluminate cement;

[0018] The nano-silica particles have a diameter of 20~100nm and are added at a dosage of 1~2% of the mass of aluminate cement.

[0019] The modification method employs ball milling modification. Zirconia balls with unequal particle diameters of 3-10 mm are selected for the milling. The milling time is 120-240 minutes, the revolution speed of the milling jar is 200-220 rpm, the rotation speed is 400-420 rpm, the ball-to-material volume ratio is 2:1.1, and the ball-to-material volume ratio of the milling jar is 1:2.

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

[0021] (1) The micro-nano gel material prepared by the present invention can be formed before hydration, and can be naturally hydrated and hardened underwater without the use of a mold.

[0022] (2) The micro-nano gel material prepared by the present invention has good magnetic properties.

[0023] (3) The addition of iron-containing solid waste in this invention reduces the amount of cement used and reduces carbon emissions generated by the use of cement. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0025] Example 1

[0026] In this embodiment, the underwater micro / nano cementitious material is prepared according to the following steps:

[0027] Step 1: Ball milling modification of iron-containing solid waste was carried out using powdered materials containing hydraulic cementitious materials and magnetic additives. After ball milling modification, magnetic agglomerates were selected using a magnetic sieving method, wherein:

[0028] The powder material containing the hydraulic gel material is composed of aluminate cement and nano-biochar, wherein the nano-biochar has a particle size of 200 nm and a pore volume of 0.06 cm³. 3 / g, with a dosage of 0.8% of the mass of aluminate cement;

[0029] The iron-containing solid waste has an iron content of 15%, a residue of ≤10% on a 35μm sieve, and is added at 40% of the mass of aluminate cement.

[0030] The magnetic supplementary material is a nano-magnetic material with a particle size of 50 nm and a dosage of 6% of the iron-containing solid waste material.

[0031] During the ball milling modification, zirconia balls with an equal particle diameter of 4 mm were selected for milling. The milling time was 150 minutes, the revolution speed of the milling jar was 160 rpm, the rotation speed was 350 rpm, the ball-to-material volume ratio was 2:1.1, and the ball-to-material volume ratio of the milling jar was 4:5.

[0032] Step 2: The magnetic agglomerate is modified by secondary ball milling with supplementary micro / nano powder materials to form an underwater micro / nano cementitious material, wherein:

[0033] The supplementary micro-nano powder material is composed of ordinary silicate cement and nano-silica.

[0034] The amount of ordinary Portland cement is 20% of the mass of aluminate cement;

[0035] The nano-silica particles have a diameter of 50 nm and are added at a dosage of 1.5% of the mass of aluminate cement.

[0036] During the ball milling modification, zirconia balls with an unequal particle diameter of 5 mm were selected for milling. The milling time was 120 minutes, the revolution speed of the milling jar was 200 rpm, the rotation speed was 420 rpm, the ball-to-material volume ratio was 2:1.1, and the ball-to-material volume ratio of the milling jar was 1:2.

[0037] Example 2

[0038] In this embodiment, the underwater micro / nano cementitious material is prepared according to the following steps:

[0039] Step 1: Ball milling modification of iron-containing solid waste was carried out using powdered materials containing hydraulic cementitious materials and magnetic additives. After ball milling modification, magnetic agglomerates were selected using a magnetic sieving method, wherein:

[0040] The powder material containing the hydraulic gel material is composed of aluminate cement and nano-zeolite, with the nano-zeolite having a particle size of 150 nm and a pore volume of 0.75 cm³. 3 / g, with a dosage of 0.5% of the mass of aluminate cement;

[0041] The iron-containing solid waste has an iron content of 12% and is added at a rate of 35% of the mass of aluminate cement.

[0042] The magnetic supplementary material is a nano-magnetic material with a particle size of 80 nm, and the dosage is 8% of the iron-containing solid waste material.

[0043] During the ball milling modification, zirconia balls with an equal particle diameter of 5 mm were selected for milling. The milling time was 180 minutes, the revolution speed of the milling jar was 150 rpm, the rotation speed was 320 rpm, the ball-to-material volume ratio was 2:1.1, and the ball-to-material volume ratio of the milling jar was 4:5.

[0044] Step 2: The magnetic agglomerate is modified by secondary ball milling with supplementary micro / nano powder materials to form an underwater micro / nano cementitious material, wherein:

[0045] The supplementary micro-nano powder material is composed of ordinary silicate cement and nano-silica.

[0046] The amount of ordinary Portland cement is 15% of the mass of aluminate cement;

[0047] The nano-silica particles have a diameter of 80 nm and are added at 2% of the mass of aluminate cement.

[0048] During the ball milling modification, zirconia balls with unequal particle diameters of 8 mm were selected for milling. The milling time was 180 minutes, the revolution speed of the milling jar was 220 rpm, the rotation speed was 400 rpm, the ball-to-material volume ratio was 2:1.1, and the ball-to-material volume ratio of the milling jar was 1:2.

Claims

1. A method for preparing underwater micro / nano cementitious materials, characterized in that... The underwater micro / nano cementitious material prepared by the method can be naturally hydrated and hardened underwater without the use of a mold; the method includes the following steps: Step 1: Modify iron-containing solid waste using a powder material containing hydraulic cementitious material and a magnetic supplementary material to form a magnetic aggregate. The powder material containing the hydraulic cementitious material is composed of aluminate cement and a nanoporous material, wherein the nanoporous material is one or both of nano-biochar and nano-zeolite; the nano-biochar has a particle size of 200–300 nm and a pore volume of 0.04–0.08 cm³. 3 / g, with an admixture dosage of 0.6–0.9% of the aluminate cement mass; the nano-zeolite has a particle size of 120–180 nm and a pore volume of 0.65–0.85 cm³. 3 / g, with a dosage of 0.3% to 0.6% of the mass of aluminate cement; The amount of nanoporous material is 0.3% to 0.9% of the mass of aluminate cement, the amount of iron-containing solid waste is 30% to 50% of the mass of aluminate cement, and the amount of magnetic supplementary material is 5% to 10% of the mass of iron-containing solid waste, wherein the iron content of the iron-containing solid waste is 8% to 18%; the magnetic supplementary material is a nanomagnetic material with a particle size of 30 to 100 nm. The modification method adopted is ball milling modification. Zirconia balls with an equal particle diameter of 3-5 mm are selected for milling. The milling time is 120-240 minutes. The revolution speed of the milling jar is 150-180 rpm and the rotation speed is 300-350 rpm. The ball-to-material volume ratio is 2:1.1 and the ball-to-material volume ratio of the milling jar is 4:

5. Step 2: The magnetic aggregate and supplementary micro-nano powder material are modified in a secondary manner to form an underwater micro-nano cementitious material, wherein: the supplementary micro-nano powder material is composed of ordinary silicate cement and nano-silica, the amount of ordinary silicate cement is 10-30% of the mass of aluminate cement, and the amount of nano-silica is 1-2% of the mass of aluminate cement. The secondary modification method adopts ball milling modification. Zirconia balls with unequal particle diameters of 3-10 mm are selected for milling. The milling time is 120-240 minutes, the revolution speed of the milling jar is 200-220 rpm, the rotation speed is 400-420 rpm, the ball-to-material volume ratio is 2:1.1, and the ball-to-material volume ratio of the milling jar is 1:

2.

2. The method for preparing underwater micro / nano cementitious materials according to claim 1, characterized in that... The particle size of the nano-silica is 20–100 nm.