Preparation and construction workability evaluation method of pouring type polyurethane concrete
By using cold-mixed and cold-laid polyether-type polyurethane binder and a workability evaluation method, the problems of poor high-temperature stability and serious pollution of cast-in-place asphalt concrete were solved, achieving low-energy consumption and environmentally friendly construction results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-03-31
AI Technical Summary
Existing cast-in-place asphalt concrete suffers from poor high-temperature stability, high energy consumption, serious pollution, and difficulty in construction and testing. In particular, it is prone to rutting and shoving defects in summer. Furthermore, the traditional asphalt mixture production process is characterized by severe energy consumption and environmental pollution.
Cold-mixed and cold-laid polyether-type polyurethane binder was used to replace asphalt to develop cast-in-place polyurethane concrete. The optimal compaction machine was determined through construction workability evaluation methods, including aggregate screening, mixture mixing and curing. The workability was evaluated using the penetration depth index D.
It improves the high-temperature stability and durability of concrete, reduces energy consumption and pollution, provides scientific construction guidance, and ensures construction quality.
Smart Images
Figure CN121762290A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of road engineering technology, specifically relating to a method for preparing and evaluating the workability of cast-in-place concrete using polyurethane as a binder. Background Technology
[0002] Guss Asphalt (GA) is a commonly used bridge deck pavement material. It has extremely low porosity, is impermeable to water, and exhibits good resistance to aging, cracking, and deformation. However, because asphalt is a viscoelastic material, it is highly temperature-sensitive and has poor high-temperature stability. Compared to other asphalt mixtures, GA has a higher asphalt-aggregate ratio and a higher proportion of fine aggregates, resulting in even worse high-temperature stability. During the high temperatures of summer, GA is highly susceptible to rutting. If the bonding between pavement layers is poor, it directly manifests as shoving. Furthermore, GA materials have poor environmental performance. Traditional asphalt mixture production typically requires heating to approximately 170°C, consuming large amounts of energy and emitting significant amounts of greenhouse gases. During construction, it releases large quantities of toxic substances, including sulfides and polycyclic aromatic hydrocarbons, polluting the environment and harming the health of production and construction workers. Even after construction, toxic gases can still be released under intense sunlight, posing a threat to human health. Compared to traditional asphalt mixtures such as AC and SMA, GA typically requires heating to over 220°C during mixing to ensure its fluidity, resulting in more severe energy consumption and environmental pollution. Therefore, developing a new type of pavement material that meets relevant technical requirements for road performance and is environmentally friendly is particularly urgent. However, currently, the compaction of polymer concrete relies on manual experience to determine the compaction time, lacking scientific rigor and stability. Summary of the Invention
[0003] To address the problems existing in the prior art, this invention uses cold-mixed, cold-laid polyether-type polyurethane binder to replace asphalt, developing a novel cast-in-place polyurethane concrete (GPC). Simultaneously, addressing the shortcomings of current methods that rely on manual experience to determine compaction times during concrete construction, which lacks scientific rigor and stability, this invention proposes a method for evaluating the workability of cast-in-place polyurethane concrete. This invention represents a significant exploration and innovation in next-generation polyurethane concrete pavement materials, possessing important theoretical and engineering value in improving the polyurethane pavement material system and promoting its application in various scenarios.
[0004] This invention provides the following technical solution:
[0005] A method for preparing and evaluating the workability of cast-in-place concrete using polyurethane as a binder, comprising the following steps:
[0006] Step 1: Screen the mineral materials and design the composition of the cast-in-place polyurethane concrete.
[0007] Step 2: Mix and cure the mixture according to the preparation process. Evaluate the workability of the mixture using a cast-in-place polyurethane concrete construction and workability testing device to determine the allowable retention time before paving the cast-in-place polyurethane concrete.
[0008] Step 3: Form the specimen within the determined allowance time, cure the specimen at a specific temperature, conduct performance tests, and compare the results with the design specifications to evaluate the performance.
[0009] Preferably, the minerals used in the cast-in-place concrete in step one are limestone (0~3mm) and basalt (3~5mm).
[0010] Preferably, the components and weight parts of the cast-in-place concrete in step one are: 30-40 parts limestone, 57-67 parts basalt, 8-10 parts polyurethane, and 2-5 parts cement.
[0011] Preferably, in step one, the polyurethane is a single-component polyether polyurethane, the cement is ordinary silicate cement, and the polyurethane is formed by addition polymerization of macromolecular polyether polyol as the soft segment and polyisocyanate and small molecule polyol as the hard segment. The polyurethane has a tensile strength (25℃) > 8MPa and an adhesive strength > 3MPa.
[0012] Preferably, the specimen formed by the preparation process in step two is obtained by the following steps:
[0013] S1. Premix cement and polyurethane in a mixer at a certain mixing rate;
[0014] S2. Add the premixed polyurethane and basalt from S1 to a mixing pot and mix, then add limestone and mix, and take the material for indoor curing.
[0015] S3. The workability of the mixture is evaluated using a cast-in-place polyurethane concrete construction and workability testing device to determine the allowable allowance time before the cast-in-place polyurethane concrete is laid.
[0016] Preferably, the mixer in S1 is a FLUKO FW30 electric mixer with a premixing time of 5 minutes and a mixing speed of 300 rpm.
[0017] Preferably, the mixing time for S2 is 2 minutes, and the curing time of the mixture in the room is 4 hours.
[0018] Preferably, in step three, the specimen is formed and cured within a determined retention time, with a curing temperature of 100℃ and a curing time of 24 hours.
[0019] Preferably, the performance tests in step three include high temperature stability, low temperature crack resistance, water stability, fatigue resistance, and aging resistance.
[0020] Preferably, the test parameters of the specimen in step three meet the following requirements: dynamic stability > 25,000 cycles / mm, maximum bending tensile strain > 15,000 με, splitting tensile strength after freeze-thaw > 0.6 MPa, fatigue life > 1.2 million cycles, and splitting tensile strength after 30 days of UV aging > 2.5 MPa.
[0021] Preferably, the cast-in-place polyurethane concrete construction and workability testing device is equipped with a penetration head, four corner supports, a counterweight rod, and a penetration bucket. The penetration head and the counterweight rod can be connected as a whole by screws. The main body of the penetration bucket is a lidless hollow cylinder, and the bottom of the bucket is a detachable circular bottom mold. The four corner supports are placed on the outside of the penetration bucket, and the counterweight rod can pass through the central hole above the four corner supports and enter the penetration bucket.
[0022] Preferably, the workability evaluation of cast-in-place polyurethane concrete uses the penetration depth index D within 60 seconds as the workability evaluation index to determine the optimal compaction time. The test procedure for the penetration depth index D within 60 seconds is as follows:
[0023] (1) Load 1kg of the mixture into the infeeding bucket and level it. Place the four corner supports on top of the infeeding bucket, and then insert the assembled infeeding head and counterweight into the center of the four corner supports.
[0024] (2) Adjust the position of the penetrating head to just above the concrete, tighten the fixing pin to fix it, and use a whiteboard marker to record the contact position D1 between the counterweight rod and the top of the four corner brackets; adjust the countdown stopwatch to 60s, start timing at the same time as loosening the fixing pin, tighten the fixing pin immediately when the timing ends, and record the contact position D2 between the counterweight rod and the top of the four corner brackets at this time.
[0025] (3) Calculate the distance between D1 and D2, accurate to millimeters; repeat the above steps three times, and take the average of the three data to obtain the workability evaluation index, the penetration depth D within 60s.
[0026] Preferably, the allowable dwell time before paving of cast-in-place polyurethane concrete is correlated with the penetration depth index D within 60 seconds.
[0027] Preferably, the minimum standard for the penetration depth index within 60 seconds is 15mm. The time required for the penetration depth index of cast-in-place polyurethane concrete to reach 15mm within 60 seconds is the allowable allowance time before the cast-in-place polyurethane concrete is laid.
[0028] Preferably, 15mm is the limit value for the performance of cast-in-place polyurethane mixture to meet the design specifications. When the penetration depth index within 60s is greater than 15mm, the cast-in-place polyurethane concrete can be laid and the performance meets the design specifications.
[0029] This invention develops a non-asphalt cold-mix, cold-lay, cast-in-place polyurethane concrete, proposes a specific preparation method and evaluation index for cast-in-place polyurethane concrete, clarifies the evaluation method for the workability of cast-in-place concrete, and solves the problems of high energy consumption, heavy pollution, poor high-temperature stability, and difficulty in on-site construction testing associated with traditional cast-in-place concrete production. The polyurethane used in this invention has good adhesion and weather resistance, effectively improving the strength, durability, and workability of concrete. The workability evaluation method can objectively and quickly assess the workability of concrete, providing effective guidance and control for construction sites. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of a workability testing apparatus for cast-in-place polyurethane concrete according to a preferred embodiment of the present invention;
[0031] Figure 2 This is a cross-sectional schematic diagram of the workability testing device for cast-in-place polyurethane concrete according to a preferred embodiment of the present invention;
[0032] Figure 3 This is a physical image of a cast-in-place polyurethane concrete workability testing apparatus according to a preferred embodiment of the present invention. Detailed Implementation
[0033] The present invention will be further illustrated below with specific examples, but the content of the present invention is not limited to the following embodiments.
[0034] Example 1
[0035] A method for preparing and evaluating the workability of cast-in-place concrete using polyurethane as a binder, comprising the following steps:
[0036] Step 1: Screen the mineral materials and design the composition of the cast-in-place polyurethane concrete. The composition and weight of the cast-in-place polyurethane concrete are as follows: 30 parts limestone, 67 parts basalt, 3 parts cement, and 8 parts polyurethane.
[0037] Step 2: Mix and cure the mixture according to the preparation process. Evaluate the workability of the mixture using a cast-in-place polyurethane concrete construction and workability testing device to determine the allowable retention time before paving the cast-in-place polyurethane concrete.
[0038] The mixture is prepared by the following steps through a preparation process involving mixing and conditioning:
[0039] S1. Premix cement and polyurethane in a mixer at a certain mixing speed. The mixer used is a FLUKO FW30 electric mixer. The premixing time is 5 minutes and the mixing speed is 300 rpm.
[0040] S2. Add the premixed polyurethane and basalt from S1 to a mixing pot and mix. Then add limestone and mix. Take out the material for indoor curing. The mixing time is 2 minutes and the indoor curing time of the mixture is 4 hours.
[0041] S3. The workability of the mixture is evaluated using a cast-in-place polyurethane concrete construction and workability testing device to determine the allowable allowance time before the cast-in-place polyurethane concrete is laid.
[0042] Step 3: Form the specimen within the determined curing time, cure the specimen at a specific temperature and then conduct performance tests, compare the results with the design specifications, and evaluate the performance. The curing temperature of the specimen is 100℃ and the curing time is 24h. The performance tests include high temperature stability, low temperature crack resistance, water stability, fatigue resistance, and aging resistance.
[0043] The cast-in-place polyurethane concrete construction and workability testing equipment used, such as Figure 1-3 As shown, the device includes a penetration head, four corner supports, a counterweight rod, and a penetration barrel. The penetration head and counterweight rod are connected as a single unit by screws. The penetration barrel is a hollow cylinder without a lid, with a detachable circular bottom mold. The four corner supports are placed on the outside of the penetration barrel, and the counterweight rod can pass through the central hole above the four corner supports into the penetration barrel. All components—the penetration head, four corner supports, counterweight rod, and penetration barrel—are made of 45# steel with a density of 7.85 g / cm³. The penetration head has a diameter of 20 mm and a height of 77 mm, with the tip of the head forming a 30° angle with its axis. The four corner supports are hollow box-type structures with a hollow circle diameter of 22 mm at the hollow position. The counterweight rod has a diameter of 20 mm, a height of 352 mm, and a weight of 0.87 kg. The main body of the insertion barrel is a lidless hollow cylinder with an inner diameter of 150mm, an outer diameter of 160mm, a thickness of 10mm, and a height of 80mm. The bottom of the barrel is a detachable circular bottom mold with a diameter of 150mm.
[0044] The workability evaluation of cast-in-place polyurethane concrete uses the penetration depth index D within 60 seconds as the workability evaluation index to determine the optimal compaction machine. The test procedure for the penetration depth index D within 60 seconds is as follows:
[0045] (1) Load 1kg of the mixture into the infeeding bucket and level it. Place the four corner supports on top of the infeeding bucket, and then insert the assembled infeeding head and counterweight into the center of the four corner supports.
[0046] (2) Adjust the position of the penetrating head to just above the concrete, tighten the fixing pin to fix it, and use a whiteboard marker to record the contact position D1 between the counterweight rod and the top of the four corner brackets; adjust the countdown stopwatch to 60s, and then start timing while loosening the fixing pin. When the timing ends, immediately tighten the fixing pin and record the contact position D2 between the counterweight rod and the top of the four corner brackets at this time.
[0047] (3) Calculate the distance between D1 and D2, accurate to millimeters; repeat the above steps three times, and take the average of the three data to obtain the workability evaluation index, the penetration depth D within 60s.
[0048] The allowable dwell time before paving cast-in-place polyurethane concrete is correlated with the penetration depth index D within 60 seconds.
[0049] The minimum standard for penetration depth within 60 seconds is 15mm. The time required for cast-in-place polyurethane concrete to reach a penetration depth of 15mm within 60 seconds is the allowable allowance time before paving the cast-in-place polyurethane concrete.
[0050] 15mm is the limit value for the performance of cast-in-place polyurethane mixture to meet the design specifications. When the penetration depth index within 60s is greater than 15mm, the cast-in-place polyurethane concrete can be laid and the performance meets the design specifications.
[0051] After processing according to step two above, workability evaluation was conducted. The time it took for the penetration depth index D of the mixture specimen to reach 15 mm within 60 seconds was 107 minutes, meaning the allowable allowance time before paving the cast-in-place polyurethane concrete was 107 minutes. Referring to step three, after curing the mixture for 4 hours, the specimens were formed after 80 minutes. The specimens were then cured at 100℃ for 24 hours, and performance tests and evaluations were conducted according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The test results and index comparisons are shown in Table 1. All test results met the design specifications.
[0052] Table 1 Test results of cast-in-place polyurethane concrete
[0053] Test Project Test results Design Indicators Dynamic stability (cycles / mm) 28694 ＞25000 Maximum bending tensile strain (με) 17835 ＞15000 Splitting tensile strength after freeze-thaw cycles (MPa) 0.69 ＞0.6 Fatigue life (10,000 cycles) 126 ＞120 Splitting tensile strength (MPa) after 30 days of UV aging 2.62 ＞2.5
[0054] Example 2
[0055] The difference between Example 2 and Example 1 is that the composition and weight of the cast-in-place polyurethane concrete are as follows: limestone 35 parts, basalt 62 parts, cement 3 parts, and polyurethane 9 parts. After processing according to step two above, the workability is evaluated. The time when the penetration depth index D of the mixture specimen reaches 15 mm within 60 seconds is 93 minutes, that is, the allowable retention time before paving the cast-in-place polyurethane concrete is 93 minutes. Referring to step three, after curing the mixture for 4 hours, wait 70 minutes to form the specimens. After curing the specimens at 100℃ for 24 hours, the performance is tested and evaluated according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The test results and index comparisons are shown in Table 2. All test results meet the design specifications.
[0056] Table 2 Test results of cast-in-place polyurethane concrete
[0057] Test Project Test results Design Indicators Dynamic stability (cycles / mm) 33658 ＞25000 Maximum bending tensile strain (με) 21542 ＞15000 Splitting tensile strength after freeze-thaw cycles (MPa) 0.72 ＞0.6 Fatigue life (10,000 cycles) 137 ＞120 Splitting tensile strength (MPa) after 30 days of UV aging 2.67 ＞2.5
[0058] Example 3
[0059] Unlike Example 1, the composition and weight of the cast-in-place polyurethane concrete are as follows: limestone 40 parts, basalt 57 parts, cement 3 parts, and polyurethane 10 parts. After processing according to step two above, the workability evaluation is carried out. The waiting time when the penetration depth index D of the mixture specimen reaches 15 within 60 seconds is 78 minutes, that is, the allowable retention time before paving the cast-in-place polyurethane concrete is 78 minutes. Referring to step three, after curing the mixture for 4 hours, the specimens are formed after waiting 60 minutes. After curing the specimens at 100℃ for 24 hours, the performance is tested and evaluated according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The test results and index comparisons are shown in Table 3. All test results meet the design specifications.
[0060] Table 3 Test results of cast-in-place polyurethane concrete
[0061] Test Project Test results Design Specifications Dynamic stability (cycles / mm) 35485 ＞25000 Maximum bending tensile strain (με) 23548 ＞15000 Splitting tensile strength after freeze-thaw cycles (MPa) 0.77 ＞0.6 Fatigue life (10,000 cycles) 142 ＞120 Splitting tensile strength (MPa) after 30 days of UV aging 2.83 ＞2.5
[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for the production and workability evaluation of cast polyurethane concrete, characterized in that, The method comprises the following steps: Step one: screen the mineral aggregate and design the composition of the cast polyurethane concrete; Step two: mix the mixture according to the preparation process, and evaluate the workability of the mixture by using the cast polyurethane concrete workability test device to determine the allowable holding time before the cast polyurethane concrete is spread; Step three: form the test piece within the determined holding time, and test the performance of the test piece after it is cured at a specific temperature, compare the test result with the design index, and evaluate the performance.
2. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, The mineral aggregate used in the cast polyurethane concrete in step one is limestone (0-3mm) and basalt (3-5mm), the limestone accounts for 30-40 parts, the basalt accounts for 57-67 parts, the polyurethane accounts for 8-10 parts, and the cement accounts for 2-5 parts.
3. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, The polyurethane in step one is a single-component polyether polyurethane, the cement is ordinary Portland cement, the polyurethane is formed by addition polymerization with macromolecular polyether polyol as soft segment, polyisocyanate and small-molecule polyol as hard segment, the tensile strength (25℃) of the polyurethane is greater than 8MPa, and the bonding strength is greater than 3MPa.
4. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, Step two comprises: S1. Pre-mix the cement and the polyurethane in a mixer at a certain stirring speed; S2. Add the pre-mixed polyurethane and the basalt in S1 into a mixing pot to mix, then add the limestone to mix, and take the mixture for indoor curing; S3. Evaluate the workability of the mixture by using the cast polyurethane concrete workability test device to determine the allowable holding time before the cast polyurethane concrete is spread.
5. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 4, characterized in that, The mixer in S1 is selected as FLUKO FW30 electric mixer, the pre-mixing time is 5min, the stirring speed is 300rpm, the mixing time in S2 is 2min, and the indoor curing time of the mixed material is 4h.
6. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, In step three, the test piece is formed within the determined holding time and is cured, the curing temperature of the test piece is 100℃, and the curing time is 24h.
7. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, The performance test in step three comprises high-temperature stability, low-temperature crack resistance, water stability, fatigue resistance and aging resistance.
8. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, The cast polyurethane concrete workability test device is provided with a penetration pressure head, a four-corner support, a counterweight rod and a penetration barrel, the penetration pressure head and the counterweight rod can be connected into one body through a screw, the penetration barrel is a hollow cylinder without a cover, the bottom of the barrel is a detachable circular bottom mold, the four-corner support is placed outside the penetration barrel, and the counterweight rod can penetrate the central hole above the four-corner support and enter the penetration barrel.
9. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 1, characterized in that, The workability evaluation of the cast polyurethane concrete uses the penetration depth index D within 60s as the workability evaluation index to determine the best compaction time, and the test steps of the penetration depth index D within 60s are as follows: (1) Put the mixture with a mass of 1kg into the penetration barrel and level it, place the four-corner support above the penetration barrel, and then insert the combined penetration pressure head and counterweight rod into the central position of the four-corner support; (2) Adjust the penetration pressure head to just contact the top of the concrete, tighten the fixing pin to fix it, record the position D1 where the counterweight rod contacts the top of the four-corner support with a whiteboard pen, adjust the countdown stopwatch to 60s, then loosen the fixing pin at the same time, start timing, and immediately tighten the fixing pin when the timing is over, and record the position D2 where the counterweight rod contacts the top of the four-corner support at this time. (3) Calculate the distance between D1 and D2, accurate to millimeter; repeat the above steps three times, and take the average of the three data to obtain the workability evaluation index 60s penetration depth D.
10. The method for preparing and evaluating workability of cast polyurethane concrete according to claim 9, characterized in that, The minimum standard of 60s penetration depth index is 15mm, and the time required for the 60s penetration depth index of cast polyurethane concrete to reach 15mm is the allowable retention time before the cast polyurethane concrete is paved.