Search

CN-121974628-A - Gray commodity concrete with red mud-fly ash synergistic color matching and preparation method thereof

CN121974628ACN 121974628 ACN121974628 ACN 121974628ACN-121974628-A

Abstract

The invention discloses gray commercial concrete which is prepared by utilizing red mud-fly ash to cooperatively color and a preparation method thereof, which comprises, by mass, 100 parts of cement, 15-25 parts of red mud, 20-30 parts of fly ash, 0-10 parts of mineral powder, 0.1-0.3 part of carbon black or iron black, 1.0-1.5 parts of nano CaCO 3 , 1.0-1.2 parts of polycarboxylate water reducer, 280-380 parts of aggregate, 40-55 parts of water, a sand ratio of 35-45%, a water-cement ratio of 0.38-0.45, a color difference delta E between the concrete and a reference sample of not more than 1.5,28 days, not less than 30 MPa, and a chloride ion diffusion coefficient of not more than 1000X 10 ‑12 m 2 /s. The invention realizes the color consistency (delta E is less than or equal to 1.5) with the standard sample prepared by ordinary Portland cement on the premise of not adding pigment and not decoloring by regulating the compound mixing proportion of the red mud and the fly ash and combining a trace amount of color matching auxiliary agent, thereby being applicable to coating-free engineering scenes such as municipal precast components, landscape concrete, pavement bricks and the like.

Inventors

  • CHEN SHUO
  • ZHOU SHUANG
  • YANG XIAOJIE
  • WU PENGFEI
  • ZHAO TIANQI
  • XUE YANG
  • GU JIARUI
  • LIU XINYUE
  • SUN TAO
  • ZHANG ZENGQI
  • LIU XIAOMING
  • YU XIAODONG
  • DONG SHANGZHU
  • MENG QINGYONG
  • FENG HONGYU
  • LIANG CHUNYANG

Assignees

  • 中国二十二冶集团有限公司
  • 北京科技大学

Dates

Publication Date
20260505
Application Date
20260130

Claims (8)

  1. 1. The gray commercial concrete with the red mud-fly ash synergistic color matching is characterized by comprising, by mass, 100 parts of cement, 15-25 parts of red mud, 20-30 parts of fly ash, 0-10 parts of mineral powder, 0.1-0.3 part of carbon black or iron black, 1.0-1.5 parts of nano CaCO 3 , 1.0-1.2 parts of polycarboxylate water reducer, 280-380 parts of aggregate, 40-55 parts of water, 35-45% of sand ratio and 0.38-0.45% of water-gel ratio, and the color difference delta E between the concrete and a reference sample is not more than 1.5,28 days compression strength not less than 30 MPa, and the chloride ion diffusion coefficient is not more than 1000 multiplied by 10 -12 m 2 /s.
  2. 2. The gray commercial concrete with the red mud-fly ash synergistic color matching according to claim 1, wherein the reference sample is a reference concrete sample with the same water-cement ratio, the same batch of cement, and no red mud, fly ash, toner and nano CaCO 3 under the same curing condition, and the 28-day CIELAB color space parameter of the reference sample is L [60.0,64.0], a [ epsilon ] +0.7, +1.7], b [ epsilon ] +3.7, +5.3].
  3. 3. The gray commercial concrete with the red mud-fly ash synergistic color matching according to claim 1 is characterized in that cement is P.O42.5 ordinary Portland cement, and aggregate is medium sand with fineness modulus of 2.6-3.0 and continuous graded broken stone with fineness of 5-20 mm.
  4. 4. The gray commercial concrete with the red mud-fly ash synergistic color matching according to claim 1, wherein the red mud is bayer process red mud, the content of Fe 2 O 3 is more than or equal to 30%, the particle size is less than or equal to 80 μm, and the color is reddish brown.
  5. 5. The gray commercial concrete with red mud-fly ash synergistic color matching according to claim 1, wherein the fly ash is class II fly ash, the color is gray, the loss on ignition is less than or equal to 5%, and the particle size is less than or equal to 45 μm.
  6. 6. The gray commercial concrete with the red mud-fly ash synergistic color matching according to claim 1, wherein the particle size of carbon black or iron black is less than or equal to 1 μm, the mixing amount is less than or equal to 0.3%, and the carbon black or iron black is ultrasonically dispersed in 20% of mixing water in advance.
  7. 7. The gray commercial concrete with the red mud-fly ash synergistic color matching according to claim 1, wherein the mass ratio of the red mud to the fly ash is 1:1-1:1.5.
  8. 8. A method for preparing gray commercial concrete by red mud-fly ash synergistic color matching as claimed in any one of claims 1 to 7, comprising the steps of: (a) Ultrasonic dispersion, namely adding carbon black or iron black into mixing water accounting for 20 percent of the total water, and performing ultrasonic dispersion for 5 minutes under the conditions of 40kHz and 300W to form stable suspension; (b) Premixing solid waste, namely dry-mixing red mud, fly ash, mineral powder and nano CaCO 3 in a stirrer for 60 seconds, wherein the mixing uniformity is more than or equal to 95%; (c) Mixing the rubber and bone, namely adding cement and aggregate, and continuously dry-mixing for 30s to enable the solid waste mixture to wrap the surface of the aggregate; (d) Wet stirring, namely adding the rest 80% of water, the polycarboxylate water reducer and the suspension in the step (a), wet mixing for 120 seconds, and controlling the discharging temperature to be less than or equal to 35 ℃ to obtain gray commercial concrete.

Description

Gray commodity concrete with red mud-fly ash synergistic color matching and preparation method thereof Technical Field The invention relates to the technical field of building materials, in particular to gray commercial concrete with red mud-fly ash synergistic color mixing and a preparation method thereof. Background Red mud is high-alkaline industrial solid waste generated in the process of extracting alumina from bauxite, is reddish brown, and contains color development components such as Fe 2O3 and the like, so that the red mud is conventionally considered to influence the appearance of concrete and limit the high-value utilization of the red mud in commercial concrete. In the current engineering, red mud is generally used in a decoloring treatment or doping amount reducing mode, so that the utilization rate of the red mud is low and the treatment cost is high. The fly ash is used as a byproduct of a thermal power plant, has light gray to dark gray in most colors, and has certain color mixing potential. In the prior art, the research of using red mud and fly ash in cooperation for color mixing instead of 'decoloring' is not carried out, and no related patent is disclosed. Disclosure of Invention In order to solve the technical problems, the invention provides gray commercial concrete which is prepared by utilizing red mud-fly ash to cooperatively color and a preparation method thereof, wherein the color of a reference sample prepared from ordinary Portland cement is consistent (delta E is less than or equal to 1.5) on the premise of not adding pigment and not carrying out decolorization treatment by regulating and controlling the compound mixing proportion of the red mud and the fly ash and combining a trace amount of color-mixing auxiliary agent, so that the concrete is suitable for coating-free engineering scenes such as municipal precast components, landscape concrete, pavement bricks and the like. In order to achieve the technical purpose, the invention adopts the following scheme: The invention provides gray commercial concrete which is cooperatively color-mixed by utilizing red mud and fly ash, comprising, by mass, 100 parts of cement, 15-25 parts of red mud, 20-30 parts of fly ash, 0-10 parts of mineral powder, 0.1-0.3 part of carbon black or iron black, 1.0-1.5 parts of nano CaCO 3, 1.0-1.2 parts of polycarboxylate water reducer, 280-380 parts of aggregate, 40-55 parts of water, a sand ratio of 35-45%, a water-cement ratio of 0.38-0.45, a color difference delta E between the concrete and a reference sample of not more than 1.5,28 days, not less than 30 MPa, and a chloride ion diffusion coefficient of not more than 1000X 10 -12 m2/s. Further, the reference sample is a reference concrete sample with the same water-cement ratio, the same batch of cement and no red mud, fly ash, toner and nano CaCO 3 under the same curing condition, and the 28-day CIELAB color space parameters of the reference sample are L, E [60.0,64.0], a, E [ +0.7, +1.7], b, E [ +3.7, +5.3]. Further, the cement is P.O 42.5 ordinary Portland cement, and the aggregate is medium sand with the fineness modulus of 2.6-3.0 and continuous graded broken stone with the fineness modulus of 5-20 mm. Further, the specific preparation method of the reference sample comprises the steps of mixing 100 parts of P.O 42.5 cement, 350 parts of standard aggregate (medium sand plus 5-20 mm broken stone), 45 parts of water and 1.0 part of polycarboxylate superplasticizer according to JGJ 55 common concrete mix proportion design rules, molding, and curing for 28 days under the condition that the (20+/-2) DEG C, RH is more than or equal to 95 percent. The CIELAB color space parameters were measured using a spectrocolorimeter under a D65 light source as a reference value for calculating Δe. Further, the red mud is Bayer process red mud, the Fe 2O3 content is more than or equal to 30%, the grain size is less than or equal to 80 mu m, and the red mud is reddish brown. Further, the fly ash is class II fly ash, the color is gray, the ignition loss is less than or equal to 5 percent, and the particle size is less than or equal to 45 mu m. Further, the particle size of the carbon black or the iron black is less than or equal to 1 mu m, the doping amount is less than or equal to 0.3 percent, and the carbon black or the iron black is ultrasonically dispersed in 20 percent of mixing water in advance before mixing. Further, the mass ratio of the red mud to the fly ash is 1:1-1:1.5. In a second aspect, the invention provides a preparation method of gray commercial concrete by utilizing red mud-fly ash to cooperatively color, which comprises the following steps: (a) Ultrasonic dispersion, namely adding carbon black or iron black into mixing water accounting for 20 percent of the total water, and performing ultrasonic dispersion for 5 minutes under the conditions of 40kHz and 300W to form stable suspension; (b) Premixing solid waste, namely dry-mixing red mud, fly ash