A type of concrete paving brick containing oily sludge pyrolysis residue

Abstract

This invention relates to a concrete paving brick made from oily sludge pyrolysis residue. It is prepared by mixing 86%–90% standard concrete and 10%–14% oily sludge pyrolysis residue by weight. Silicate cement, fine aggregate, and water are added to a mixer according to the standard concrete weight ratio. After the mortar has fully coated the inner wall of the mixer, it is poured out. The following steps are taken: Fine aggregate, cement, coarse aggregate, fine aggregate, and water are weighed according to a weight ratio of 16:51:25:8. The coarse aggregate, fine aggregate, and residue are added first and mixed. Cement is then added and mixed again. Half the water and water-reducing agent are added and mixed. The water-reducing agent dosage is 0.7% of the unit cement weight. Finally, the remaining water is added. The mixture is then molded and cured to obtain the oily sludge pyrolysis residue concrete paving brick. This invention achieves high-value utilization of oily sludge pyrolysis residue and reduces carbon emissions from concrete production.

Description

Technical Field

[0001] This invention relates to the field of road materials technology, specifically to a novel type of road brick made from oily sludge pyrolysis residue and its preparation method. Background Technology

[0002] Traditional concrete paving bricks are highly dependent on non-renewable resources. At the same time, the production of cement and sand and gravel has high carbon emissions. If the large-scale production of traditional concrete paving bricks continues, it will undoubtedly exacerbate the pressure to reduce carbon emissions. Promoting the large-scale replacement of traditional concrete raw materials such as cement and natural sand and gravel with solid waste is an important means to alleviate the shortage of civil engineering resources and the problem of solid waste disposal.

[0003] Oily sludge pyrolysis residue is rich in silicon and aluminum, possessing potential as a civil engineering material. However, it suffers from poor gradation, exhibiting a porous structure, low strength, and high water absorption. Directly replacing cement and aggregates in large quantities for concrete paving brick production would lead to excessive adsorption of mixing water and weakened interlocking between aggregates, resulting in decreased strength and stiffness of the paving bricks, increased drying shrinkage, and severely impacting the road's load-bearing capacity and service life. Therefore, it is necessary to determine the optimal mix proportion for preparing concrete paving bricks from oily sludge pyrolysis residue to achieve large-scale engineering applications of this type of solid waste and improve its resource utilization efficiency. Summary of the Invention The purpose of this invention is to provide a concrete paving brick made from oily sludge pyrolysis residue, which solves the problem of low utilization of residue generated after the pyrolysis treatment of oily sludge.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: This oily sludge pyrolysis residue concrete paving brick is prepared from reference concrete and oily sludge pyrolysis residue, wherein the reference concrete accounts for 86%~90% by mass, and the oily sludge pyrolysis residue accounts for 10%~14% by mass; the reference concrete is made of silicate cement, coarse aggregate, fine aggregate, water, and water-reducing agent, wherein the mass ratio of silicate cement, coarse aggregate, fine aggregate, and water is 16:51:25:8, and the water-reducing agent dosage is 0.7% of the unit cement weight; the paving brick preparation method is as follows: (1) Cleaning the vent Pour silicate cement, fine aggregate and water into the mixer according to the standard concrete mass ratio and mix for 3 minutes. After the inner wall of the mixer is fully coated with mortar, pour out the cement mortar. (2) Mixing ingredients According to the above mix proportion, weigh the fine aggregate, cement, coarse aggregate, water, water-reducing agent and oily sludge pyrolysis residue. First, add the coarse aggregate, fine aggregate and residue, and stir for three minutes. Then add the cement and stir for three minutes. Next, add 1 / 2 of the water and water-reducing agent and stir for three minutes. Finally, add the remaining water, stir for two minutes, pour out and test the slump. (3) Parts Add the mixed concrete to the paving brick mold, start the vibrator and insert the test block, insert it quickly and pull it out slowly, and vibrate for 30 seconds. (4) Maintenance After standing for 24 hours, the mold was removed, each specimen was marked, and then placed in a saturated calcium hydroxide solution at a temperature of 20±2℃ for standard curing for 28 days.

[0005] In the above scheme, the surface of the concrete pavement bricks containing oily sludge pyrolysis residue has honeycomb-like CSH and flaky Ca(OH)2 hydration products, and the microstructure is dense.

[0006] In the above scheme, the pyrolysis residue of oily sludge is fine sand, and the maximum dry density of the pyrolysis residue of oily sludge is 1720 kg / m³. 3 The apparent density is 2572 kg / m³. 3 The bulk density is 1430 kg / m³. 3 Plasticity index I P The permeability coefficient is 8.5. k 20 1.07×10 -3 cm / s, organic matter content is 2.49%, and resilience modulus E The compressibility is 14.435~25.428 MPa, and the compressibility coefficient is α. 1-2 The pressure is 0.02~0.07 MPa. -1 The moisture content is 0.

[0007] In the above scheme, when the pyrolysis residue of oily sludge is added to the reference concrete, the physical encapsulation and chemical adsorption of cement hydration product CSH reduce the leaching concentration of As to within the range of GB5749-2022 standard, so that the heavy metal detection of the pyrolysis residue of oily sludge meets the standard.

[0008] In the above scheme, the reference concrete is C40 plain concrete. The mix proportion of C40 reference concrete is obtained by volume method, and three water-cement ratios that meet the strength requirements are designed: 0.50, 0.47 and 0.44. Finally, based on the principle of using the minimum amount of cement, the water-cement ratio of 0.50 is selected, and C40 plain concrete is set as the standard comparison ratio.

[0009] In the above scheme, the cement is PO 42.5 ordinary Portland cement produced by Daqing Oilfield Cement Co., Ltd., the coarse aggregate is crushed stone with a particle size of 4.75~26.5mm, the fine aggregate is natural river sand with a particle size of less than 4.75mm, the oily sludge pyrolysis residue is provided by the oily sludge treatment station of the Ninth Oil Production Plant of Daqing Oilfield, the water reducing agent is naphthalene-based high-efficiency water reducing agent produced by Shandong Wanshan Chemical Co., Ltd., and the water is domestic water.

[0010] Beneficial effects: 1. This invention utilizes oily sludge pyrolysis residue as a substitute material for concrete in the preparation of concrete paving bricks. Through appearance quality inspection, compressive strength, freeze-thaw resistance, abrasion resistance, water absorption, and anti-slip tests, and based on the comprehensive test results, the optimal mix proportion of concrete paving bricks incorporating oily sludge pyrolysis residue is obtained. This technology not only enables the safe disposal and resource utilization of oily sludge pyrolysis residue industrial waste, reducing environmental pressure and the amount of concrete raw materials used, but also has significant implications for reducing engineering costs and promoting the sustainable development of road engineering.

[0011] 2. Excellent road performance and controllable paving cost.

[0012] This invention replaces fine aggregate with pyrolysis residue, resulting in materials with high strength, good stability, and simple preparation, which can ensure the performance and lifespan of paving bricks; at the same time, it disposes of oilfield solid waste, reduces the consumption of fine aggregate in natural sand and gravel, and lowers road construction costs.

[0013] 3. Solid waste recycling yields significant social benefits. The application of oily sludge pyrolysis residue in road engineering solves the problem of oilfield solid waste treatment, enabling the large-scale recycling and utilization of oily sludge pyrolysis residue and reducing the production cost of paving bricks. This allows for the sustainable utilization of oilfield solid waste, promotes the development of road transportation construction, and yields significant economic and social benefits.

[0014] 4. Excellent raw material compatibility and superior interfacial adhesion.

[0015] The pyrolysis residue used comes from the oily sludge treatment station of the Ninth Oil Production Plant of Daqing Oilfield Company. It is a black granular substance with a rough and porous surface, which can improve the interfacial adhesion with cement-based materials and ensure the integrity and structural stability of the system.

[0016] 5. The raw material source is stable, and large-scale application is feasible.

[0017] The pyrolysis residue is derived from solid waste from oilfield operations. The raw materials are stable and widely available, requiring no additional investment. This can improve the recycling rate of solid waste, reduce engineering costs, lay the foundation for the large-scale promotion of materials, and has good industrialization prospects.

[0018] 6. This invention rationally introduces oily sludge pyrolysis residue into concrete paving bricks, which can not only realize the high-value utilization of oily sludge pyrolysis residue and help break the resource dilemma of the traditional paving brick industry, but also reduce the carbon emissions of concrete production and provide a new technical path for the green transformation of the traditional construction industry. Detailed Implementation The present invention will be further described below: Example 1

[0019] This type of oily sludge pyrolysis residue concrete paving brick is prepared from reference concrete and oily sludge pyrolysis residue. The reference concrete accounts for 90% of the mass percentage, and the oily sludge pyrolysis residue accounts for 10% of the mass percentage, with the total mass percentage of the reference concrete and oily sludge pyrolysis residue being 100%. The reference concrete includes ordinary Portland cement, coarse aggregate, fine aggregate, water, and a water-reducing agent. The mass ratio of the Portland cement, coarse aggregate, fine aggregate, and water is 16:51:25:8, and the water-reducing agent dosage is 0.7% of the unit cement weight.

[0020] The preparation method of this concrete paving brick containing oily sludge pyrolysis residue includes the following steps: S1. Weigh out 90% of the reference concrete and 10% of the oily sludge pyrolysis residue by mass percentage, ensuring the total amount is accurate to 100%. This helps maintain the stability of the raw material ratio and avoids uneven strength caused by mixing deviations. Add these raw materials to a mixing device for initial mixing. Control the mixing time within a preset range, such as within a few minutes, to ensure uniform particle distribution and form a composite material. This uniformity contributes to the subsequent formation of dense paving bricks and improves the overall mechanical properties of the bricks.

[0021] For example, in actual production, first weigh 100 kg of raw materials, including 90 kg of reference concrete raw materials and 10 kg of oily sludge pyrolysis residue. Then use a high-speed mixing device to mix at 800 revolutions per minute for 5 minutes to form a uniform slurry. This uniformity helps to evenly disperse the oily sludge pyrolysis residue and improve the strength and stability of the final brick.

[0022] When preparing the reference concrete, ordinary silicate cement is first obtained as a cementing material to provide a basis for hydration reaction. Then, fine aggregate is added to fill the small gaps, and crushed stone is used as coarse aggregate to support the overall frame. After mixing according to the mass ratio, the initial reference concrete is prepared. This mixing method ensures that the initial pore structure is evenly distributed, which is beneficial to improving the overall stability of the substrate.

[0023] S2. Mix the reference concrete and the oily sludge pyrolysis residue evenly to obtain a mixture. When mixing the reference concrete and the oily sludge pyrolysis residue, a progressive mixing method is used. Weigh cement, coarse aggregate, fine aggregate, water, water-reducing agent, and oily sludge pyrolysis residue according to the planned test mix proportion. First, add the coarse aggregate, fine aggregate, and oily sludge pyrolysis residue, and mix for three minutes. Then add the cement and mix for three minutes. Next, add half of the water and water-reducing agent and mix for three minutes. Finally, add the remaining water, mix for two minutes, and then pour out the mixture. This operation facilitates thorough mixing of the aggregates, promotes interfacial reactions, and improves the mechanical properties of the brick. Direct one-time mixing may result in excessively high local concentrations. The progressive method achieves uniform dispersion, thereby reducing porosity defects and improving durability during subsequent molding.

[0024] S3. Add the mixed concrete to the mold, start the vibrator and insert the test block, insert it quickly and pull it out slowly, and vibrate for 30 seconds. S4. After standing for 24 hours, remove the mold, mark each specimen, and then place it in a saturated calcium hydroxide solution at a temperature of 20±2℃ for standard curing for 28 days.

[0025] S5 Quality Inspection and Acceptance After the curing period, in accordance with the national standard "Concrete Pavement Bricks" (GB28635-2012), appearance quality, compressive strength, freeze-thaw, abrasion resistance, water absorption and anti-slip tests were carried out on concrete pavement bricks with different mix proportions containing oily sludge pyrolysis residue to test whether their performance met the performance index requirements of Cc40 concrete pavement bricks.

[0026] Example 2 The difference between this embodiment and Embodiment 1 is that the reference concrete is 86% and the oily sludge pyrolysis residue is 14%.

[0027] The cement used in this invention is P.O42.5 ordinary Portland cement produced by Daqing Oilfield Cement Co., Ltd. The coarse aggregate is crushed stone with a particle size of 4.75~26.5mm, the fine aggregate is natural river sand with a particle size of less than 4.75mm, the pyrolysis residue of oily sludge is provided by the oily sludge treatment station of the Ninth Oil Production Plant of Daqing Oilfield, the water reducing agent is naphthalene-based high-efficiency water reducing agent produced by Shandong Wanshan Chemical Co., Ltd., and the water used is domestic water.

[0028] Density tests were conducted on the pyrolysis residue of oily sludge, and the maximum dry density, apparent density, and bulk density of the residue were found to be 1720 kg / m³. 3 2572kg / m 3 and 1430kg / m 3 According to GB / T14684-2022, the apparent density of construction sand must be greater than 2500 kg / m³. 3 Loose bulk density greater than 1400 kg / m³ 3 Therefore, this residue can be applied in the field of civil engineering.

[0029] The non-uniformity coefficient of the pyrolysis residue of oily sludge was obtained by conducting particle analysis, liquid limit and plastic limit tests, permeability tests, organic matter content tests, moisture content tests, resilience modulus tests, and consolidation tests. C u All values ​​are less than 5, indicating that the residue is of uniform particle size and poorly graded. In the pyrolysis residue of oily sludge, particles of 0.35~0.075mm account for more than 50% of the total particle mass, indicating that the residue is fine sand. The plasticity index of the pyrolysis residue of oily sludge... I PThe permeability coefficient is 8.5. k 20 1.07×10 -3 cm / s, organic matter content of 2.49%, and resilience modulus E The compressibility is 14.435~25.428 MPa and the compressibility coefficient is α. 1-2 The pressure is 0.02~0.07 MPa. -1 The residue was ultimately determined to be fine sand, belonging to the low compressibility category, and not to be organic matter. Moisture content tests revealed that the oily sludge pyrolysis residue had a moisture content of 0.

[0030] ICP-MS was used to quantitatively detect the leaching concentrations of 12 heavy metal pollutants (including Ba, Zn, As, Cr, Cu, Hg, Ag, Cd, Pb, Be, Ni, and Se) in the pyrolysis residue of oily sludge. The results showed that the leaching concentration of As exceeded the limit of GB5749-2022, indicating a potential environmental risk from the direct use of oily sludge pyrolysis residue in road engineering. When incorporated into benchmark concrete, the physical encapsulation and chemical adsorption of cement hydration product CSH reduced the leaching concentration of As to within the standard range, and the heavy metal detection results for the oily sludge pyrolysis residue all met the standards.

[0031] Referring to the industry standard "Specification for Mix Proportion Design of Ordinary Concrete" (JGJ55-2011), C40 plain concrete was used as the reference concrete. The mix proportion of the C40 reference concrete was obtained by volume method, and three water-cement ratios that meet the strength requirements were designed: 0.50, 0.47, and 0.44. Finally, based on the principle of minimizing the amount of cement used, a water-cement ratio of 0.50 was selected, and C40 plain concrete was set as the standard comparison ratio.

[0032] XRD analysis revealed the presence of CSH in concrete paving bricks prepared with oily sludge pyrolysis residue, indicating that this type of mixture can generate hydration products. Scanning electron microscopy further confirmed the feasibility of preparing concrete paving bricks containing oily sludge pyrolysis residue by observing honeycomb-like (CSH) and lamellar (Ca(OH)2) hydration products on the material surface, demonstrating a dense microstructure.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the reference concrete is 85% and the oily sludge pyrolysis residue is 15%.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that the reference concrete is 80% and the oily sludge pyrolysis residue is 20%.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that the reference concrete is 70% and the oily sludge pyrolysis residue is 30%.

[0036] Comparative Example 4 The reference concrete was 100% and the oily sludge pyrolysis residue was 0%.

[0037] The method for preparing the concrete paving bricks includes the following steps: S1. Mix the ordinary Portland cement, fine aggregate and coarse aggregate of the concrete evenly to obtain a mixture; S2. Add the mixed concrete to the mold, start the vibrator and insert the test block, insert it quickly and pull it out slowly, and vibrate for 30 seconds. S3. After standing for 24 hours, remove the mold, mark each specimen, and then place it in a saturated calcium hydroxide solution at a temperature of 20±2℃ for standard curing for 28 days.

[0038] Performance testing According to the national standard "Concrete Pavement Bricks" (GB28635-2012), the test items include appearance quality inspection, compressive strength test, freeze-thaw test, abrasion resistance test, water absorption test, and anti-skid test. Through the test, the appearance quality, compressive strength, freeze resistance, abrasion resistance, water absorption rate, and anti-skid properties of concrete pavement bricks with different mix proportions are determined, and the optimal pyrolysis residue admixture ratio that can meet the Cc40 concrete pavement brick standard requirements is determined.

[0039] Appearance quality inspection tests revealed significant honeycomb defects on the surfaces of specimens with residue content of Comparative Examples 1, 2, and 3; elliptical pores were found on the surfaces of specimens with residue content of Examples 1 and 2; and the surface of specimen 4 was smooth and flat. According to the appearance quality requirements in the national standard "Concrete Pavement Bricks" (GB28635-2012), specimens with residue content of Comparative Examples 4, 1, and 2 met the standards, while specimens with residue content of Comparative Examples 1, 2, and 3 failed to meet the standards.

[0040] Compressive strength test This test was conducted in accordance with the national standard "Concrete Paving Bricks" (GB28635-2012) to determine the compressive strength of concrete paving bricks. A 500T universal compression testing machine was used for the test.

[0041] The operating procedures for the experiment are as follows: Since the test specimens are cured in water, when the curing period of the specimens reaches 28 days, there is no need to soak them in water for another 24 hours. After removing the specimens from the water, clean the surface of the specimens.

[0042] Place it in the center of the lower pressure plate of the testing machine. Because the surface of the specimen is uneven, the pressure surface of the specimen needs to be leveled with sand before loading.

[0043] Start the testing machine and apply the load continuously and uniformly at a rate of 8 kN / s until the specimen fails. Record the failure load.

[0044] Compressive strength tests were conducted to determine the compressive strengths of concrete paving brick specimens with six mix proportions: Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3. The results were 54.24 MPa, 49.96 MPa, 46.54 MPa, 45.32 MPa, 42.79 MPa, and 0 MPa, respectively. Except for Comparative Example 3, the compressive strengths of specimens from Examples 1, 2, 1, 2, and 4 all met the compressive strength requirements for Cc40 concrete paving bricks in the national standard "Concrete Paving Bricks (GB28635-2012)".

[0045] freeze-thaw test This test was conducted in accordance with the national standard "Concrete Pavement Bricks" (GB28635-2012) to determine the compressive strength of concrete pavement bricks before and after freeze-thaw cycles. A freeze-thaw testing machine and a 500T universal pressure testing machine were used in the test.

[0046] The operating procedures during the experiment are as follows: Since the test specimens are cured in water, when the curing period reaches 28 days, they are taken out of the curing tank and placed in the water tank of the freeze-thaw test machine, and water is added so that the water level is about 20 mm above the top surface of the specimen.

[0047] The testing machine parameters were set to a minimum temperature of -15℃ and a maximum temperature of 10℃ at the center of the specimen. One cycle of the specimen experiencing both the minimum and maximum temperatures constituted one freeze-thaw cycle. The freeze-thaw testing machine was started and 50 cycles were performed.

[0048] After completing 50 freeze-thaw cycles, the specimens were removed from the water, the surface water was wiped off, and the surface of the specimens was inspected for peeling, delamination, and cracks.

[0049] Place it in the center of the lower pressure plate of the testing machine. Because the surface of the specimen is uneven, the pressure surface of the specimen needs to be leveled with sand before loading.

[0050] Start the testing machine and apply the load continuously and uniformly at a rate of 8 kN / s until the specimen fails. Record the failure load.

[0051] Freeze-thaw tests were conducted to determine the strength loss rate of concrete paving bricks with residual admixtures after 50 freeze-thaw cycles. According to the national standard "Concrete Paving Bricks" (GB28635-2012) for Cc40 concrete paving bricks, the strength loss rate should not exceed 20%. The strength loss rates of six mix proportions—Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3—were measured to be 13.93%, 18.63%, 18.89%, 32.00%, 100%, and 100%, respectively. The results show that the strength loss rates of the mix proportions of Comparative Example 4, Example 1, and Example 2 are all less than 20%, while the strength loss rates of the mix proportions of Comparative Example 1, Comparative Example 2, and Comparative Example 3 all exceed 20%. Therefore, Comparative Example 4, Example 1, and Example 2 are deemed to meet the freeze-thaw resistance standard, while the other mix proportions are deemed not to meet the standard.

[0052] Abrasion test This test was conducted in accordance with the national standard "Test Method for Abrasion Resistance of Concrete and its Products" (GB / T16925-1997) to determine the abrasion resistance of concrete paving bricks. A ball bearing abrasion tester was used for the test.

[0053] The operating procedures for the experiment are as follows: Place the specimen with the wear-bearing surface facing upwards, horizontally within the specimen fixture of the abrasion testing machine, and clamp it after leveling. Place the grinding head on the wear-bearing surface of the specimen, ensuring that the raceway at the lower end of the hollow shaft is precisely pressing against the grinding head. The position of the hollow shaft should be adjusted so that it remains unrestrained in the vertical direction throughout the entire test.

[0054] Turn on the water source so that water flows continuously from the hollow rotating shaft to the surface of the test piece being ground, and is sufficient to wash away the debris ground off during the test.

[0055] Start the motor, and stop the machine after the grinding head has pre-ground for 30 revolutions. Read the percentage reading and measure the initial grinding groove depth. Then, stop the machine once every 1000 revolutions of the grinding head, read the percentage reading, and measure the depth. Continue until the grinding head reaches 5000 revolutions or the grinding groove depth reaches more than 1.5mm. The test ends when the final grinding head revolutions and the final grinding groove depth are recorded.

[0056] Abrasion resistance tests were conducted, and the abrasion resistance values ​​of the six mix proportions (Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) were determined to be 2.81, 2.10, 2.01, 1.98, 1.05, and 0.79, respectively. According to the national standard "Concrete Paving Bricks" (GB28635-2012), the abrasion resistance of Cc40 concrete paving bricks should be >1.9. Therefore, the abrasion resistance of the specimens from Comparative Example 4, Example 1, Example 2, and Comparative Example 1 was determined to be up to standard, while the abrasion resistance of the specimens from the other mix proportions was not up to standard.

[0057] Water absorption test This test was conducted in accordance with the national standard "Concrete Pavement Bricks" (GB28635-2012) to determine the water absorption of concrete pavement bricks. An oven was used for the test.

[0058] The specimens were dried in an oven at 105℃. The specimens were taken out and measured every 4 hours until the specimen mass remained unchanged. This was considered the dry mass of the specimens.

[0059] After cooling the specimen to room temperature, place it upright on its side in a water tank and pour in water at a temperature of 10~30℃. During immersion, the water level should be about 20mm above the specimen.

[0060] After soaking in water for 24 hours, remove the specimen from the water, wipe off the moisture on the surface of the specimen with a wrung-out damp cloth, and weigh the specimen.

[0061] Water absorption tests were conducted, and the water absorption rates of the six mix proportions (Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) were determined to be 1.5%, 1.8%, 1.8%, 2.5%, 2.7%, and 3.2%, respectively. According to the national standard "Concrete Paving Bricks" (GB28635-2012), the water absorption rate of Cc40 concrete paving bricks should be <6.5%. Therefore, it can be determined that the water absorption performance of the mix proportions of Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 all meet the standard.

[0062] Anti-slip test This test was conducted in accordance with GB28635-2012 to determine the water absorption of concrete pavement bricks. A pendulum friction coefficient tester was used for the test.

[0063] Sprinkle water on the surface of the specimen and use a scraper to remove the mud and other adhering substances from the surface.

[0064] Adjust the height of the pendulum so that the sliding length of the rubber sheet on the specimen surface is 126 + 1 mm. Spray water on the specimen surface again to keep it moist, press the release switch to make the pendulum fall and slide across the specimen surface, and read the value indicated by the pointer, which is the measured value.

[0065] Do not record the first measurement. Repeat the measurement five times and record the results. If the range of the five values ​​is greater than 3 BPN, check the cause and make adjustments, then repeat the operation. Take the average of the five measurements as the measurement value for each specimen. The final result is the arithmetic mean of the measurements of the five specimens, accurate to 1 BPN.

[0066] Anti-slip tests were conducted, and the anti-slip properties of the six mix proportions (Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) were determined to be 65.56 BPN, 66.44 BPN, 67.93 BPN, 68.34 BPN, 69.68 BPN, and 74.74 BPN, respectively. According to the national standard "Concrete Paving Bricks" (GB28635-2012), Cc40 concrete paving bricks have an anti-slip property ≥ 60 BPN. Therefore, the anti-slip performance of the mix proportions of Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 was determined to meet the standard.

[0067] By conducting mix proportion tests on concrete paving bricks with oily sludge pyrolysis residue, the performance indicators of concrete paving bricks with six mix proportions (Comparative Example 4, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) such as appearance quality, strength, frost resistance, wear resistance, water absorption, and anti-slip properties were obtained. The test results are summarized in Table 1.

[0068] Table 1 Performance test results of paving bricks

[0069] The test results were compared with the specifications for Cc40 concrete paving bricks to determine the optimal incorporation ratio of oily sludge pyrolysis residue to meet the Cc40 concrete paving brick standard. Table 1 shows that the mix proportions of Comparative Example 4, Example 1, and Example 2 all met the standards, while the appearance quality and frost resistance of the mix proportion of Example 3 did not meet the standards. The appearance quality, frost resistance, and abrasion resistance of the mix proportion of Comparative Example 2 also did not meet the standards. The tests revealed that the appearance quality, compressive strength, frost resistance, and abrasion resistance of the mix proportion of Comparative Example 3 did not meet the standards. Therefore, the optimal incorporation ratio of oily sludge pyrolysis residue in concrete paving bricks was determined to be 10%–14%.

Claims

1. An oil sludge pyrolysis residue-containing concrete paving brick, characterized by: This type of oily sludge pyrolysis residue concrete paving brick is prepared from reference concrete and oily sludge pyrolysis residue. The reference concrete accounts for 86%–90% of the mass, and the oily sludge pyrolysis residue accounts for 10%–14% of the mass. The reference concrete is made of silicate cement, coarse aggregate, fine aggregate, water, and a water-reducing agent. The mass ratio of silicate cement, coarse aggregate, fine aggregate, and water is 16:51:25:8, and the water-reducing agent dosage is 0.7% of the unit cement weight. The paving brick preparation method is as follows: (1) Cleaning the vent Pour silicate cement, fine aggregate and water into the mixer according to the standard concrete mass ratio and mix for 3 minutes. After the inner wall of the mixer is fully coated with mortar, pour out the cement mortar. (2) Mixing ingredients According to the above mix proportion, weigh the fine aggregate, silicate cement, coarse aggregate, water, water-reducing agent and oily sludge pyrolysis residue. First, add the coarse aggregate, fine aggregate and residue, and stir for three minutes. Then add the cement and stir for three minutes. Next, add 1 / 2 of the water and water-reducing agent and stir for three minutes. Finally, add the remaining water, stir for two minutes, pour out and test the slump. (3) Parts Add the mixed concrete to the paving brick mold, start the vibrator and insert the test block, insert it quickly and pull it out slowly, and vibrate for 30 seconds. (4) Maintenance After standing for 24 hours, the mold was removed, each specimen was marked, and then placed in a saturated calcium hydroxide solution at a temperature of 20±2℃ for standard curing for 28 days.

2. The oil-containing sludge pyrolysis residue concrete paving brick according to claim 1, characterized in that: The surface of the concrete paving bricks containing oily sludge pyrolysis residue has honeycomb-like CSH and flaky Ca(OH)2 hydration products, and the microstructure is dense.

3. The oil-containing sludge pyrolysis residue concrete paving brick according to claim 2, characterized in that: The oily sludge pyrolysis residue is fine sand, with a maximum dry density of 1720 kg / m³. 3 The apparent density is 2572 kg / m³. 3 The bulk density is 1430 kg / m³. 3 Plasticity index I P The permeability coefficient is 8.

5. k 20 1.07×10 -3 cm / s, organic matter content is 2.49%, and resilience modulus E The compressibility is 14.435~25.428 MPa, and the compressibility coefficient is α. 1-2 The pressure is 0.02~0.07 MPa. -1 The moisture content is 0.

4. The oil-containing sludge pyrolysis residue concrete paving brick according to claim 3, characterized in that: When the oily sludge pyrolysis residue is incorporated into the reference concrete, the physical encapsulation and chemical adsorption of the cement hydration product CSH reduce the leaching concentration of As to within the range of GB5749-2022 standard, ensuring that the heavy metal detection of the oily sludge pyrolysis residue meets the standard.

5. The oil-containing sludge pyrolysis residue concrete paving brick according to claim 4, characterized in that: The reference concrete is C40 plain concrete. The mix proportion of the C40 reference concrete was determined by the volume method, and three water-cement ratios that meet the strength requirements were designed: 0.50, 0.47, and 0.

44. Finally, based on the principle of minimizing the amount of cement used, a water-cement ratio of 0.50 was selected, and C40 plain concrete was set as the standard comparison ratio.

6. The oil-containing sludge pyrolysis residue concrete paving brick according to claim 5, characterized in that: The cement is PO 42.5 ordinary Portland cement produced by Daqing Oilfield Cement Co., Ltd., the coarse aggregate is crushed stone with a particle size of 4.75~26.5mm, the fine aggregate is natural river sand with a particle size of less than 4.75mm, the pyrolysis residue of oily sludge is provided by the oily sludge treatment station of the Ninth Oil Production Plant of Daqing Oilfield, the water reducing agent is naphthalene-based high-efficiency water reducing agent produced by Shandong Wanshan Chemical Co., Ltd., and the water is domestic water.

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