High-performance pervious concrete material based on recycled aggregate and preparation method thereof

Abstract

A high-performance pervious concrete material based on recycled aggregate and a preparation method thereof, the material can adaptively adjust the mix proportion according to the actual performance parameters of the recycled aggregate, realize a water permeability coefficient of >=1.0mm / s while ensuring a compressive strength of >=20MPa, and the recycled aggregate replacement rate is >=50%.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-performance permeable concrete material based on recycled aggregate and its preparation method. Background Technology

[0002] Recycled aggregate permeable concrete offers dual value in the resource utilization of construction waste and the construction of sponge cities. However, the sources of recycled aggregates are complex, and their performance parameters, such as crushing value and water absorption rate, fluctuate significantly. Furthermore, there is an inherent contradiction between the strength and permeability coefficient of permeable concrete. Traditional permeable concrete materials typically use fixed formulas, which cannot be flexibly adjusted according to the actual quality of the aggregates, leading to unstable product performance.

[0003] In existing technologies, for example, patent CN118084401A discloses a permeable concrete for construction waste, but its formula ratio is fixed and cannot adapt to the fluctuations in the performance of recycled aggregates. Patent CN121318210A prepares permeable concrete by optimizing aggregate gradation, but does not involve aggregate strengthening pretreatment or data-driven mix design. Although patent CN121999935A provides a strength prediction method, it only considers the single relationship between strength and porosity and does not incorporate the intrinsic characteristics of recycled aggregates.

[0004] In summary, the existing technology has the following drawbacks: 1. The existing recycled aggregate permeable concrete material formula is fixed and cannot compensate for the fluctuation of aggregate performance, resulting in poor product quality stability.

[0005] 2. The contradiction between strength and permeability remains unresolved; existing materials are unable to meet structural strength requirements while ensuring high permeability.

[0006] 3. The aggregate strengthening treatment is disconnected from the material formulation, and the strengthening effect cannot be quantified and utilized in the formulation design. Summary of the Invention

[0007] The present invention aims to solve the above-mentioned problems in the prior art and provide a high-performance permeable concrete material based on recycled aggregate and its preparation method. The material can adaptively adjust the mix ratio according to the actual performance parameters of the recycled aggregate, and achieve a permeability coefficient of ≥1.0mm / s while ensuring a compressive strength of ≥20MPa, and the replacement rate of recycled aggregate is ≥50%.

[0008] The present invention adopts the following technical solution: A high-performance permeable concrete material based on recycled aggregate, characterized in that it is composed of the following components in parts by weight: (a) Cement: 300-450 parts, preferably P.O42.5 or P.O52.5 ordinary Portland cement; (b) Recycled coarse aggregate: 1400-1800 parts, with a replacement rate of 50%-100% for recycled aggregate; (c) Mineral admixtures: 0-100 parts; (d) Admixture: 2-8 parts; (e) Water: 100-160 parts, the water-cement ratio of this concrete is w / b = 0.28-0.38.

[0009] The recycled coarse aggregate has a crushing value Cv ≤ 30%, a water absorption rate Wa ≤ 8%, and a mud content Mc ≤ 3%.

[0010] The material has a compressive strength fc ≥ 20 MPa, a permeability coefficient k ≥ 1.0 mm / s, and a freeze-thaw resistance Fd ≥ 50 freeze-thaw cycles after 28 days of standard curing.

[0011] The mineral admixture is one or more of fly ash, slag powder, and silica fume; the additive is one or more of polycarboxylate superplasticizer, air-entraining agent, and thickener.

[0012] It also contains reinforcing fibers with a volume content of Vf = 0.05%-0.15%, wherein the reinforcing fibers are selected from polyvinyl alcohol fibers or basalt fibers.

[0013] The recycled coarse aggregate has a particle size of 5-10 mm or 5-16 mm.

[0014] A method for preparing high-performance permeable concrete material based on recycled aggregate as described in any of the preceding claims, characterized by comprising the following steps: (a) The recycled coarse aggregate is crushed, screened, washed, and dried until the moisture content is ≤2%; (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc and the target permeability coefficient k as constraints, the optimal water-cement ratio w / b, the bone-cement ratio a / c and the target porosity pt are determined through multi-objective optimization. (c) A two-stage feeding process is used for mixing; Pre-wet and mix the recycled aggregate with 50% water for 30 seconds, add cement, mineral admixtures and remaining water and mix for 90 seconds, add admixtures and mix for 60 seconds; (d) Perform tamping or vibration molding; (e) Cured under standard conditions for 28 days.

[0015] Step (a) also includes an enhancement treatment step, which is carried out by water washing and soaking in dilute acetic acid or CO2 carbonization.

[0016] The permeability coefficient correction formula used is k = [pt³ × de²] / [180 × (1-pt)²] × (1-Cv / 100) × (1-Wa / 100).

[0017] Step (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc ≥ 20 MPa and the target permeability coefficient kt ≥ 1.0 mm / s as constraints, the optimal water-cement ratio w / b = 0.28-0.38, the bone-cement ratio a / c = 3.5-5.5, and the target porosity pt = 18-25% are determined through multi-objective optimization.

[0018] Beneficial effects: 1. The material composition has self-adaptive capability: Through intelligent design methods, the mix proportion is adaptively adjusted according to the actual performance parameters of recycled aggregates to ensure the stability of material performance under different batches of aggregates.

[0019] 2. Excellent overall product performance: Under the condition of recycled aggregate replacement rate ≥50%, it simultaneously achieves synergistic performance indicators of compressive strength ≥20MPa and permeability coefficient ≥1.0mm / s.

[0020] 3. High-value utilization of recycled aggregates: The replacement rate can reach 100%, and the material performance is guaranteed through intelligent design.

[0021] 4. Product quality is predictable and designable: Product performance can be estimated before material preparation through performance prediction models. Attached Figure Description

[0022] Figure 1 This is a system architecture block diagram provided for an embodiment of the present invention.

[0023] Figure 2 The preparation process flow diagram provided for the embodiments of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments.

[0025] A high-performance permeable concrete material based on recycled aggregate, characterized in that it is composed of the following components in parts by weight: (a) Cement: 300-450 parts, preferably P.O42.5 or P.O52.5 ordinary Portland cement; (b) Recycled coarse aggregate: 1400-1800 parts, with a replacement rate of 50%-100% for recycled aggregate; (c) Mineral admixtures: 0-100 parts; (d) Admixture: 2-8 parts; (e) Water: 100-160 parts, the water-cement ratio of this concrete is w / b = 0.28-0.38.

[0026] The recycled coarse aggregate has a crushing value Cv ≤ 30%, a water absorption rate Wa ≤ 8%, and a mud content Mc ≤ 3%.

[0027] The material has a compressive strength fc ≥ 20 MPa, a permeability coefficient k ≥ 1.0 mm / s, and a freeze-thaw resistance Fd ≥ 50 freeze-thaw cycles after 28 days of standard curing.

[0028] The mineral admixture is one or more of fly ash, slag powder, and silica fume; the additive is one or more of polycarboxylate superplasticizer, air-entraining agent, and thickener.

[0029] It also contains reinforcing fibers with a volume content of Vf = 0.05%-0.15%, wherein the reinforcing fibers are selected from polyvinyl alcohol fibers or basalt fibers.

[0030] The recycled coarse aggregate has a particle size of 5-10 mm or 5-16 mm.

[0031] A method for preparing high-performance permeable concrete material based on recycled aggregate as described in any of the preceding claims, characterized by comprising the following steps: (a) The recycled coarse aggregate is crushed, screened, washed, and dried until the moisture content is ≤2%; (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc and the target permeability coefficient kt as constraints, the optimal water-cement ratio w / b, the bone-cement ratio a / c and the target porosity pt are determined through multi-objective optimization. (c) A two-stage feeding process is used for mixing; Pre-wet and mix the recycled aggregate with 50% water for 30 seconds, add cement, mineral admixtures and remaining water and mix for 90 seconds, add admixtures and mix for 60 seconds; (d) Perform tamping or vibration molding; (e) Cured under standard conditions for 28 days.

[0032] Step (a) also includes an enhancement treatment step, which is carried out by water washing and soaking in dilute acetic acid or CO2 carbonization.

[0033] The permeability coefficient correction formula used is k = [pt³ × de²] / [180 × (1-pt)²] × (1-Cv / 100) × (1-Wa / 100).

[0034] The optimization formula for step b is the mix proportion optimization formula (minimum deviation optimization model): min(w / b, a / c, pt) [(fc - fc,t) / fc,t]² + [(k - kt) / kt]² Step (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc,t ≥ 20 MPa and the target permeability coefficient kt ≥ 1.0 mm / s as constraints, the optimal water-cement ratio w / b, bone-cement ratio a / c and target porosity pt are determined through multi-objective optimization.

[0035] Example 1 Composition: 380 parts P.O42.5 cement, 1600 parts recycled coarse aggregate (5-10mm, Cv=22%, Wa=5.8%), 60 parts fly ash, 4 parts polycarboxylate superplasticizer, and 130 parts water.

[0036] Parameters: w / b=0.30, a / c=3.6, pt=20%, Rr=100%.

[0037] Performance: 28-day compressive strength fc=28.6 MPa, permeability coefficient k=1.8 mm / s, mass loss rate after 50 freeze-thaw cycles is 3.2%.

[0038] Example 2 Composition: 400 parts P.O52.5 cement, 1650 parts recycled coarse aggregate (5-16mm, Cv=18%, Wa=4.2%), 30 parts silica fume, 5 parts polycarboxylate superplasticizer, and 120 parts water.

[0039] Parameters: w / b=0.28, a / c=3.8, pt=18%, Rr=100%.

[0040] Performance: 28-day compressive strength fc = 35.2 MPa, permeability coefficient k = 1.2 mm / s Example 3 Composition: 350 parts P.O42.5 cement, 1400 parts recycled coarse aggregate (5-10mm, Cv=26%, Wa=6.5%), 400 parts natural crushed stone, 50 parts fly ash, 3.5 parts polycarboxylate superplasticizer, and 140 parts water.

[0041] Parameters: w / b=0.35, a / c=4.5, pt=23%, Rr=78%.

[0042] Performance: 28-day compressive strength fc = 22.3 MPa, permeability coefficient k = 2.5 mm / s.

[0043] Technical effect comparison

[0044] The symbols and formulas of this invention are explained below:

[0045] The key technical parameters are as follows:

[0046] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A high-performance permeable concrete material based on recycled aggregate, characterized in that, It consists of the following components in parts by mass: (a) Cement: 300-450 parts, preferably P.O42.5 or P.O52.5 ordinary Portland cement; (b) Recycled coarse aggregate: 1400-1800 parts, with a replacement rate of 50%-100% for recycled aggregate; (c) Mineral admixtures: 0-100 parts; (d) Admixture: 2-8 parts; (e) Water: 100-160 parts, the water-cement ratio of this concrete is w / b = 0.28-0.

38.

2. The high-performance permeable concrete material based on recycled aggregate according to claim 1, characterized in that, The recycled coarse aggregate has a crushing value Cv ≤ 30%, a water absorption rate Wa ≤ 8%, and a mud content Mc ≤ 3%.

3. A high-performance permeable concrete material based on recycled aggregate according to claim 1 or 2, characterized in that, The material has a compressive strength fc ≥ 20 MPa, a permeability coefficient k ≥ 1.0 mm / s, and a freeze-thaw resistance Fd ≥ 50 freeze-thaw cycles after 28 days of standard curing.

4. The high-performance permeable concrete material based on recycled aggregate according to claim 1, characterized in that, The mineral admixture is one or more of fly ash, slag powder, and silica fume; the additive is one or more of polycarboxylate superplasticizer, air-entraining agent, and thickener.

5. The high-performance permeable concrete material based on recycled aggregate according to claim 1, characterized in that, It also contains reinforcing fibers with a volume content of Vf = 0.05%-0.15%, wherein the reinforcing fibers are selected from polyvinyl alcohol fibers or basalt fibers.

6. The high-performance permeable concrete material based on recycled aggregate according to claim 1, characterized in that, The recycled coarse aggregate has a particle size of 5-10 mm or 5-16 mm.

7. A method for preparing high-performance permeable concrete material based on recycled aggregate as described in any one of claims 1-6, characterized in that, Includes the following steps: (a) The recycled coarse aggregate is crushed, screened, washed, and dried until the moisture content is ≤2%; (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc and the target permeability coefficient k as constraints, the optimal water-cement ratio w / b, the bone-cement ratio a / c and the target porosity pt are determined through multi-objective optimization. (c) A two-stage feeding process is used for mixing; Pre-wet and mix the recycled aggregate with 50% water for 30 seconds, add cement, mineral admixtures and remaining water and mix for 90 seconds, add admixtures and mix for 60 seconds; (d) Perform tamping or vibration molding; (e) Cured under standard conditions for 28 days.

8. The method for preparing high-performance permeable concrete material based on recycled aggregate as described in claim 7, characterized in that, Step (a) also includes an enhancement treatment step, which is carried out by water washing and soaking in dilute acetic acid or CO2 carbonization.

9. The method for preparing high-performance permeable concrete material based on recycled aggregate as described in claim 7, characterized in that, The permeability coefficient correction formula used is k = [pt³ × de²] / [180 × (1-pt)²] × (1-Cv / 100) × (1-Wa / 100).

10. The method for preparing high-performance permeable concrete material based on recycled aggregate as described in claim 7, characterized in that, Step (b) Detect the crushing value Cv, water absorption rate Wa, and mud content Mc of the recycled aggregate, and input them into the performance prediction model. With the target compressive strength fc ≥ 20 MPa and the target permeability coefficient kt ≥ 1.0 mm / s as constraints, the optimal water-cement ratio w / b = 0.28-0.38, the bone-cement ratio a / c = 3.5-5.5, and the target porosity pt = 18-25% are determined through multi-objective optimization.

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