A concrete material for simulating dynamic and static mechanical properties of dense reef limestone and a preparation method thereof

Abstract

The application relates to the technical field of geotechnical engineering physical model test materials, and discloses a concrete material for simulating the dynamic and static mechanical properties of dense reef limestone and a preparation method thereof, which is prepared from the following raw materials: cement, reef limestone machine-made sand, gypsum, heavy spar powder, a foaming agent, a water reducing agent, a retarder, fibers and water. The reef limestone machine-made sand is added, and the proportion of each component is controlled, so that materials are taken from the local place, the reef limestone mined on the spot is used as an aggregate after being crushed and screened, the process is simple, and the material transportation and construction cost is greatly reduced. The prepared concrete not only can restore the static mechanical properties of the reef limestone, but also can effectively reflect the dynamic mechanical properties of the reef limestone under the impact, so that a reliable test basis is provided for related engineering research.

Description

Technical Field

[0001] This invention relates to the field of materials technology for physical model testing in geotechnical engineering, and in particular to a concrete material for simulating the dynamic and static mechanical properties of dense reef limestone and its preparation method. Background Technology

[0002] During island and reef construction, since these islands and reefs are generally far from the mainland, using traditional concrete materials would require long-distance transportation of raw materials such as sand, gravel, and fresh water from the inland, significantly increasing transportation costs and logistical burdens. This would result in unnecessary losses in resource input and project progress, making it difficult to guarantee project efficiency and economic viability. Therefore, developing new concrete materials that are suitable for local island and reef resources has become an urgent need and an important technological direction for advancing island and reef construction.

[0003] Current research mostly uses static parameters as evaluation indicators for the performance of reef limestone concrete materials. However, during the service period, island and reef engineering projects often face high strain rate dynamic loads such as earthquakes and explosions in addition to conventional static loads. Such dynamic loads often become the dominant factors that cause structural damage accumulation and even failure.

[0004] Although some patents claim to consider "dynamic similarity," the evaluation indicators they actually use are still limited to static parameter systems.

[0005] Therefore, there is an urgent need for a concrete material whose static and dynamic properties can match those of natural reef limestone to meet the requirements of island and reef engineering under extreme loads. Summary of the Invention

[0006] This invention provides a concrete material and its preparation method for simulating the dynamic and static mechanical properties of dense reef limestone, aiming to solve the problem of the lack of a concrete material whose static and dynamic properties can match those of natural reef limestone, so as to meet the needs of island and reef engineering under extreme loads.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A concrete material for simulating the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts), wherein A / C = 0.5~1.5, D / B = 0.1~0.45, (B+D) / (A+C) = 0.4~0.6, E / (A+C) = 0.01~0.015, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.005~0.015, and I / (A+C) = 0.45.

[0008] Furthermore, the cement is CA-50 aluminate cement.

[0009] Furthermore, the particle size range of the manufactured sand from the reef limestone is 4 to 40 mesh, the particle size range of the gypsum is 80 to 120 mesh, and the particle size range of the barite powder is 200 to 400 mesh.

[0010] Furthermore, the foaming agent is a cement or mortar concrete foaming agent, which is diluted with water at a ratio of 1:30 before foaming.

[0011] Furthermore, the water-reducing agent is a polycarboxylate high-performance water-reducing agent, the retarder is a crystalline retarder, and the water is tap water.

[0012] Furthermore, the fiber is a polypropylene fiber with a length of 9 mm.

[0013] A method for preparing the above-mentioned concrete material for simulating the dynamic and static mechanical properties of dense reef limestone includes the following steps: 1) Weigh and mix cement, reef limestone manufactured sand, gypsum and barite powder according to the proportions; 2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly evenly dispersed and without clumping. 3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to prepare an aqueous solution of the admixture; 4) Slowly pour the aqueous solution of the additive into the dry mixture of step 2), stir for 3-5 minutes to obtain a uniform and fluid matrix slurry; 5) Weigh the foaming agent stock solution according to the ratio, add 30 times the amount of dilution water, and use a foaming machine to make fine and stable foam; 6) Pour the foam into the base slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; 7) Pour the mixture into the mold, vibrate and shake it to form the concrete. After initial setting, demold it and cure it to obtain the concrete material.

[0014] Furthermore, the maintenance period is 21 days.

[0015] Furthermore, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0016] The application of the concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone, or the concrete material obtained by the preparation method described above, in the study of the mechanical response characteristics of reef limestone.

[0017] The beneficial effects of this invention are: (1) This invention uses locally sourced reef limestone as raw material, which is crushed and screened and then used directly as aggregate. The process is simple and greatly reduces the cost of material transportation and construction. (2) The concrete produced can not only restore the static mechanical properties (density, porosity, compressive strength, tensile strength, elastic modulus, Poisson's ratio) of the reef limestone, but also effectively reflect its dynamic mechanical properties under impact (dynamic peak stress under different impact pressures), thus realizing the simulation of the mechanical behavior of the original rock and providing a reliable experimental basis for related engineering research. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of concrete material samples from Example 1 and Comparative Example 1-1 of the present invention; Figure 2 This is a density distribution curve of concrete material in various embodiments of the present invention; Figure 3 These are porosity distribution curves of concrete materials in various embodiments of the present invention; Figure 4 This is a uniaxial compressive strength distribution curve of concrete material in various embodiments of the present invention; Figure 5 This is a uniaxial tensile strength distribution curve of concrete material in various embodiments of the present invention; Figure 6 The diagram shows the Poisson's ratio distribution curves of concrete materials in various embodiments of the present invention. Figure 7 This is a graph showing the distribution curves of the elastic modulus of concrete materials in various embodiments of the present invention; Figure 8 The diagram shows the dynamic compressive strength distribution curves of concrete materials under 0.1 MPa impact air pressure in various embodiments of the present invention. Figure 9 The diagram shows the dynamic compressive strength distribution curves of concrete materials under 0.3 MPa impact air pressure in various embodiments of the present invention. Figure 10 The diagram shows the dynamic compressive strength distribution curves of concrete materials under 0.5 MPa impact air pressure in various embodiments of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments.

[0020] The concrete materials prepared in Example 1 and Comparative Example 1-1 below are as follows: Figure 1 As shown, Figure 1 From left to right, the first and third samples are samples of Example 1, and the second and fourth samples are samples of Comparative Example 1-1.

[0021] Based on the results of numerous experimental studies, the mechanical parameters of dense reef limestone are shown in Table 1: Table 1 Dynamic and static mechanical parameters of dense reef limestone

[0022] The experimental results of the following examples and comparative examples are as follows: Figures 2-10 As shown.

[0023] Example 1 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C=1, D / B=0.1, (B+D) / (A+C)=0.4, E / (A+C)=0.01, F / (A+C)=0.0025, G / C=0.0015, H / (A+B+C+D)=0.005, and I / (A+C)=0.45.

[0024] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 20 mesh, the particle size of gypsum is 90 mesh, the particle size of barite powder is 200 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0025] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0026] The mechanical parameters of the prepared concrete material are shown in Table 2.

[0027] Table 2 shows the dynamic and static mechanical parameters of the concrete material prepared in Example 1.

[0028] The test results show that the dynamic and static mechanical parameters of the concrete material meet the requirements, therefore the concrete material prepared by this mix proportion meets the requirements.

[0029] Comparative Example 1-1 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), calcareous sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C=1, D / B=0.1, (B+D) / (A+C)=0.4, E / (A+C)=0.01, F / (A+C)=0.0025, G / C=0.0015, H / (A+B+C+D)=0.005, and I / (A+C)=0.45.

[0030] The selected cement is CA-50 aluminate cement, the calcareous sand has a particle size of 20 mesh, the gypsum has a particle size of 90 mesh, the barite powder has a particle size of 200 mesh, the foaming agent is a cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is a polycarboxylate high-performance water-reducing agent, the retarder is a crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0031] The above raw materials are prepared according to the following steps: (1) Weigh the cement, calcareous sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0032] The mechanical parameters of the prepared concrete material are shown in Table 3.

[0033] Table 3. Dynamic and static mechanical parameters of the concrete material prepared based on Comparative Example 1-1

[0034] The results of Example 1 and Comparative Example 1-1 show that, under the premise of maintaining consistent mix proportions and particle sizes, replacing the manufactured sand from reef limestone with calcareous sand reduces the compressive strength, tensile strength, and kinetic parameters of the concrete, making it impossible to prepare concrete materials that meet the requirements. This is due to the difference in particle structure between the two: manufactured sand from reef limestone, through diagenesis and cementation, has fewer micropores within its particles, resulting in higher inherent strength, and its sharp edges after breakage can form a more stable skeleton. Calcareous sand, on the other hand, retains a large number of internal pores characteristic of protozoan skeletons, making it prone to particle breakage under stress, leading to earlier yielding of the specimens.

[0035] Comparative Examples 1-2 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C=2, D / B=0.1, (B+D) / (A+C)=0.4, E / (A+C)=0.01, F / (A+C)=0.0025, G / C=0.0015, H / (A+B+C+D)=0.005, and I / (A+C)=0.45.

[0036] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 20 mesh, the particle size of gypsum is 90 mesh, the particle size of barite powder is 200 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0037] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0038] The mechanical parameters of the prepared concrete material are shown in Table 4.

[0039] Table 4. Dynamic and static mechanical parameters of concrete materials prepared based on Comparative Examples 1-2

[0040] The results of Example 1 and Comparative Examples 1-2 show that when only the cement-gypsum ratio is changed, the kinetic parameters of the material do not meet the requirements, therefore the concrete material prepared under this mix proportion does not meet the requirements. The main reason is that simply increasing the cement-gypsum ratio actually reduces the water-cement ratio, resulting in a denser and stronger hardened material.

[0041] Example 2 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 0.5, D / B = 0.3, (B+D) / (A+C) = 0.5, E / (A+C) = 0.012, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.01, and I / (A+C) = 0.45.

[0042] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand from the reef limestone is 30 mesh, the particle size of the gypsum is 80 mesh, the particle size of the barite powder is 300 mesh, the foaming agent is a cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is a polycarboxylate high-performance water-reducing agent, the retarder is a crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9 mm, and the water is tap water.

[0043] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0044] The mechanical parameters of the prepared concrete material are shown in Table 5.

[0045] Table 5. Dynamic and static mechanical parameters of the concrete material prepared in Example 2.

[0046] The test results show that the dynamic and static mechanical parameters of the concrete material meet the requirements, therefore the concrete material prepared by this mix proportion meets the requirements.

[0047] Comparative Example 2 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 0.5, D / B = 0.6, (B+D) / (A+C) = 0.5, E / (A+C) = 0.012, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.01, and I / (A+C) = 0.45.

[0048] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand from the reef limestone is 30 mesh, the particle size of the gypsum is 80 mesh, the particle size of the barite powder is 300 mesh, the foaming agent is a cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is a polycarboxylate high-performance water-reducing agent, the retarder is a crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9 mm, and the water is tap water.

[0049] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0050] The mechanical parameters of the prepared concrete material are shown in Table 6.

[0051] Table 6. Dynamic and static mechanical parameters of the concrete material prepared based on Comparative Example 2

[0052] The results of Example 2 and Comparative Example 2 show that when only the ratio of barite powder to reef limestone manufactured sand is changed, the dynamic and static strength parameters of the material do not meet the requirements. Therefore, the concrete material prepared under this mix proportion does not meet the requirements. The main reason is that an increase in the ratio of barite powder to reef limestone manufactured sand means an increase in the barite powder content. Barite particles themselves have low hardness and are brittle, making them prone to breakage under pressure, forming a large number of weak points inside the concrete, resulting in a decrease in overall strength.

[0053] Example 3 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 1.5, D / B = 0.45, (B+D) / (A+C) = 0.6, E / (A+C) = 0.015, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.015, and I / (A+C) = 0.45.

[0054] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 25 mesh, the particle size of gypsum is 100 mesh, the particle size of barite powder is 400 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0055] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0056] The mechanical parameters of the prepared concrete material are shown in Table 7.

[0057] Table 7. Dynamic and static mechanical parameters of the concrete material prepared in Example 3.

[0058] The test results show that the dynamic and static mechanical parameters of the concrete material meet the requirements, therefore the concrete material prepared by this mix proportion meets the requirements.

[0059] Comparative Example 3 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 1.5, D / B = 0.45, (B+D) / (A+C) = 0.3, E / (A+C) = 0.015, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.015, and I / (A+C) = 0.45.

[0060] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 25 mesh, the particle size of gypsum is 100 mesh, the particle size of barite powder is 400 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0061] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0062] The mechanical parameters of the prepared concrete material are shown in Table 8.

[0063] Table 8. Dynamic and static mechanical parameters of the concrete material prepared based on Comparative Example 3

[0064] The results of Example 3 and Comparative Example 3 show that when only the aggregate-cement ratio is changed, the density, porosity, and kinetic parameters of the material do not meet the requirements. Therefore, the concrete material prepared under this mix proportion does not meet the requirements. The main reason is that the aggregate itself constitutes the high-strength skeleton of the concrete. Reducing its proportion means that under stress, more of the load is transferred to the much lower-strength cementitious material, thus weakening the overall load-bearing capacity. At the same time, excessive paste will increase the hardening shrinkage of the material, causing more microcracks inside, ultimately leading to increased porosity and decreased density and strength of the concrete.

[0065] Example 4 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 0.5, D / B = 0.45, (B+D) / (A+C) = 0.5, E / (A+C) = 0.013, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.011, and I / (A+C) = 0.45.

[0066] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 25 mesh, the particle size of gypsum is 100 mesh, the particle size of barite powder is 300 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0067] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0068] The mechanical parameters of the prepared concrete material are shown in Table 9.

[0069] Table 9. Dynamic and static mechanical parameters of the concrete material prepared in Example 4

[0070] The test results show that the dynamic and static mechanical parameters of the concrete material meet the requirements, therefore the concrete material prepared by this mix proportion meets the requirements.

[0071] Comparative Example 4-1 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 0.5, D / B = 0.45, (B+D) / (A+C) = 0.5, E / (A+C) = 0.02, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.011, and I / (A+C) = 0.45.

[0072] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 25 mesh, the particle size of gypsum is 100 mesh, the particle size of barite powder is 300 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0073] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0074] The mechanical parameters of the prepared concrete material are shown in Table 10.

[0075] Table 10. Dynamic and static mechanical parameters of the concrete material prepared based on Comparative Example 4-1

[0076] The results of Example 4 and Comparative Example 4-1 show that when only the proportion of foaming agent is changed, the peak stress of the material under impact air pressures of 0.3 MPa and 0.5 MPa does not meet the requirements. Therefore, the concrete material prepared by this mix proportion does not meet the requirements. The main reason is that the introduction of a large number of air bubbles occupies the internal space of the concrete, reducing the cross-section of the solid skeleton that actually bears the load. The pore walls of the air bubbles are extremely thin and discontinuous, making them prone to stress concentration and rapid crushing under stress. At the same time, excessive air bubble content can also easily cause air bubble merging, floating, and slurry settling, forming interconnected large pores and defects with extremely uneven structure, ultimately leading to a decrease in strength as the density decreases.

[0077] Comparative Example 4-2 The concrete material used to simulate the dynamic and static mechanical properties of dense reef limestone is composed of the following raw materials in parts by weight: cement (A parts), reef limestone manufactured sand (B parts), gypsum (C parts), barite powder (D parts), foaming agent (E parts), water-reducing agent (F parts), retarder (G parts), fiber (H parts), and water (I parts). Wherein, A / C = 0.5, D / B = 0.45, (B+D) / (A+C) = 0.5, E / (A+C) = 0.013, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.02, and I / (A+C) = 0.45.

[0078] The selected cement is CA-50 aluminate cement, the particle size of the manufactured sand of reef limestone is 25 mesh, the particle size of gypsum is 100 mesh, the particle size of barite powder is 300 mesh, the foaming agent is cement and mortar concrete foaming agent, the stock solution of which is diluted with water at a ratio of 1:30, the water-reducing agent is polycarboxylate high-performance water-reducing agent, the retarder is crystalline retarder, the fiber is polypropylene fiber with a fiber length of 9mm, and the water is tap water.

[0079] The above raw materials are prepared according to the following steps: (1) Weigh the cement, reef limestone manufactured sand, gypsum and barite powder according to the proportion and mix them evenly; (2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are visibly dispersed evenly and without clumping. (3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to make an aqueous solution of admixture; (4) Slowly pour the aqueous solution of the additive into the dry mixture of step (2) and stir for 3 to 5 minutes to obtain a uniform and fluid matrix slurry; (5) Weigh the foaming agent stock solution according to the proportion, add 30 times the mass of dilution water, and use a foaming machine to make fine and stable foam; (6) Pour the foam into the matrix slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; (7) Pour the mixture into the mold, vibrate and shake to form the concrete. After initial setting, demold and cure to obtain concrete material. The curing time is 21 days, the curing temperature is 25±2℃, and the curing humidity is ≥90%.

[0080] The mechanical parameters of the prepared concrete material are shown in Table 11.

[0081] Table 11. Dynamic and static mechanical parameters of the concrete material prepared based on Comparative Example 4-2

[0082] The results of Example 4 and Comparative Example 4-2 show that the tensile strength of the material does not meet the requirements when only the fiber ratio is changed; therefore, the concrete material prepared by this mix proportion does not meet the requirements. Mechanistically, the randomly distributed fibers form a three-dimensional support network in the concrete matrix. When the matrix cracks under tension, the fibers spanning both sides of the crack can continue to bridge and transfer tensile stress through interfacial adhesion, preventing premature crack penetration and thus increasing the ultimate load that the specimen can withstand before tensile failure.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A concrete material for simulating the dynamic and static mechanical properties of dense reef limestone, characterized in that, It is composed of the following raw materials in parts by weight: cement A, reef limestone manufactured sand B, gypsum C, barite powder D, foaming agent E, water-reducing agent F, retarder G, fiber H, and water I, wherein A / C = 0.5~1.5, D / B = 0.1~0.45, (B+D) / (A+C) = 0.4~0.6, E / (A+C) = 0.01~0.015, F / (A+C) = 0.0025, G / C = 0.0015, H / (A+B+C+D) = 0.005~0.015, and I / (A+C) = 0.

45.

2. The concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 1, characterized in that: The cement is CA-50 aluminate cement.

3. The concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 1, characterized in that: The particle size range of the manufactured sand from the reef limestone is 4 to 40 mesh, the particle size range of the gypsum is 80 to 120 mesh, and the particle size range of the barite powder is 200 to 400 mesh.

4. The concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 1, characterized in that: The foaming agent is a cement or mortar concrete foaming agent, which is diluted with water at a ratio of 1:30 before foaming.

5. The concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 1, characterized in that: The water-reducing agent is a polycarboxylate high-performance water-reducing agent, the retarder is a crystalline retarder, and the water is tap water.

6. The concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 1, characterized in that: The fiber is a polypropylene fiber with a length of 9 mm.

7. A method for preparing a concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to any one of claims 1 to 6, characterized in that: Includes the following steps: 1) Weigh and mix cement, reef limestone manufactured sand, gypsum and barite powder according to the proportions; 2) Weigh the fibers according to the proportion, sprinkle them evenly into the dry mixture, and continue to dry mix for 1 to 2 minutes until the fibers are evenly dispersed and there are no clumps. 3) Weigh the retarder and water-reducing agent according to the proportion, add them to the water in sequence, and stir until completely dissolved to prepare an aqueous solution of the admixture; 4) Slowly pour the aqueous solution of the additive into the dry mixture of step 2), stir for 3-5 minutes to obtain a uniform and fluid matrix slurry; 5) Weigh the foaming agent stock solution according to the ratio, add 30 times the amount of dilution water, and use a foaming machine to make foam; 6) Pour the foam into the base slurry and stir for 1-2 minutes until the foam is evenly distributed, then stop stirring; 7) Pour the mixture into the mold, vibrate and shake it to form the concrete. After initial setting, demold it and cure it to obtain the concrete material.

8. The method for preparing concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 7, characterized in that: The maintenance period is 21 days.

9. The method for preparing concrete material for simulating the dynamic and static mechanical properties of dense reef limestone according to claim 7, characterized in that: The curing temperature is 25±2℃, and the curing humidity is ≥90%.

10. The application of the concrete material for simulating the dynamic and static mechanical properties of dense reef limestone as described in any one of claims 1 to 6, or the concrete material obtained by the preparation method described in any one of claims 7 to 9, in the study of the mechanical response characteristics of reef limestone.

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