Core-shell-structure lightweight aggregate prepared by cold bonding method and preparation method thereof

Abstract

The invention discloses a core-shell-structure lightweight aggregate prepared by a cold bonding method and a preparation method thereof. The preparation method comprises the following steps: preparinga calcined clay-based environment-friendly cementing material from ordinary Portland cement, calcined clay, limestone powder and gypsum in proportion; putting core material particles into a lightweight aggregate granulation device, then adding the calcined clay-based environment-friendly cementing material, and uniformly spraying a mixture for granulation to form primary cold-bonded aggregate; carrying out primary maintenance on the primarily-generated cold-bonded aggregate, soaking the primarily-generated cold-bonded aggregate in a solution containing organic acid or phenol compounds, takingout the primarily-generated cold-bonded aggregate, airing, and repeatedly spraying a calcium hydroxide aqueous solution on the surface of the aggregate to form aggregate with a super-hydrophobic surface; and subjecting the aggregate with the super-hydrophobic surface to water for secondary maintenance to produce the super-hydrophobic high-strength lightweight aggregate. According to the core-shell structure lightweight aggregate and the preparation method thereof, energy is saved, consumption is low, the processing flow is simplified, solid waste recycling can be achieved, the water absorption rate is low, and the single bearing capacity is high.

Description

technical field [0001] The invention relates to the technical field of aggregate preparation for construction, in particular to a core-shell structure lightweight aggregate with low water absorption and high particle bearing capacity, which is energy-saving and low-consumption, simplifies the processing flow, and can realize solid waste recycling in real time. its preparation method. Background technique [0002] Classified according to the preparation and production process of ceramsite, it can be divided into sintered ceramsite, intumescent ceramsite, and non-fired ceramsite. The traditional production process is to use raw materials such as clay, fly ash, and limestone powder to produce artificial lightweight aggregate through high-temperature sintering technology in a rotary kiln. These production techniques all belong to the firing method. The preparation process not only consumes a lot of energy, but also emits a large amount of toxic and harmful gases such as sulfur ...

AI Technical Summary

Problems solved by technology

[0005] 1. The lightweight aggregate produced by high-temperature sintering technology has high energy consumption, poor production environment and backward production technology

[0006] 2. The existing unfired ceramsite has low strength, low particle bearing capacity, and is easy to carbonize. It is mainly used in non-load-bearing structures such as small blocks and partitions

[0007] 3. The water absorption rate of traditional ceramsite aggregate is relatively high, usually 5%-25%. If the water absorption rate is too high, the fire resistance performance is not good, and it is easy to cause concrete bursting at high temperature

[0008] 4. Most of the existing unfired ceramsite is based on powders such as fly ash or slag, and the sustainability of raw material supply is not strong

[0009] 5. Existing raw materials for ceramsite preparation rely excessively on and consume natural clay and shale resources, while tailings and solid waste are used as raw materials as auxiliary materials to prepare ceramsite. There is still a big gap in the green circular economy

[0010] 6. At present, in order to reduce the water absorption rate of ceramsite, chemical methods are commonly used, using silane-type hydrophobic agents, but this type of hydrophobic agent is expensive and needs to be coated by machinery or manpower, which is time-consuming and expensive

[0011] 7. The strength of ceramsite sintered at high temperature is fixed because it has no active material or the active material has been excited, and it will no longer develop, and its mechanical properties will deteriorate over time and its strength will decrease

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