A fiber-reinforced gypsum composite material and a gypsum mold

Abstract

This invention belongs to the field of building materials technology, specifically relating to a fiber-reinforced gypsum composite material and a gypsum mold. The invention provides a fiber-reinforced gypsum composite material comprising the following components in parts by weight: 100 parts phosphogypsum, 45-60 parts water, 0.5-3.5 parts calcium oxide, 0.2-0.6 parts polypropylene fiber, 0.1-0.3 parts polyvinyl alcohol fiber, 0.1-0.6 parts polyphosphate, 0.2-0.6 parts silane coupling agent, 0.1-0.3 parts latex, and 0.1-0.5 parts water-reducing agent. In this invention, the polypropylene fiber and polyvinyl alcohol fiber work synergistically to optimize the force transmission path, resulting in gypsum molds prepared from the fiber-reinforced gypsum composite material possessing excellent crack resistance and breakage resistance.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a fiber-reinforced gypsum composite material and a gypsum mold. Background Technology

[0002] Hollow core slab structures are a new type of floor system that incorporates hollow formwork into the traditional flat slab system, forming a top slab, bottom slab, and internal cavity. By employing optimized cross-sectional shapes, shortening force transmission paths, and increasing slab thickness, hollow core slab structures achieve certain structural parameter optimizations. While ensuring safety, they offer significant advantages such as material savings, shorter construction periods, environmental friendliness, sound insulation, and reduced costs.

[0003] Currently, my country's annual phosphogypsum emissions are 75-80 million tons, with stockpiles exceeding 600 million tons and a utilization rate of less than 40%. More seriously, most phosphate fertilizer enterprises and phosphogypsum stockpiles are located in the Yangtze River basin, and phosphogypsum contains harmful impurities such as phosphorus, fluorine, and organic matter that are easily leached by rainwater, causing increasingly prominent ecological and environmental problems in the Yangtze River basin and urgently requiring resource-based disposal. Therefore, effectively utilizing phosphogypsum to ultimately achieve zero emissions and dispose of stockpiles is an inevitable requirement for the sustainable development of the phosphate fertilizer industry and the ecological protection of the Yangtze River basin.

[0004] Pre-forming phosphogypsum into gypsum molds is a green and low-carbon filler promoted in China. When used in hollow floor slab structures, it can fully demonstrate significant advantages such as being green, low-carbon, utilizing waste, saving materials, shortening construction time, and reducing costs. It can effectively promote the high-quality and large-scale utilization of phosphogypsum, creating good economic and environmental benefits. It is a highly innovative technical path.

[0005] However, since gypsum is a brittle material, gypsum molds are prone to cracking and damage during concrete pouring and vibration, which can lead to engineering quality problems. Summary of the Invention

[0006] The purpose of this invention is to provide a fiber-reinforced gypsum composite material and a gypsum mold. The gypsum mold prepared from the fiber-reinforced composite material provided by this invention has good crack resistance and damage resistance.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a fiber-reinforced gypsum composite material, comprising the following components in parts by weight:

[0009] The ingredients are: 100 parts phosphogypsum, 45-60 parts water, 0.5-3.5 parts calcium oxide, 0.2-0.6 parts polypropylene fiber, 0.1-0.3 parts polyvinyl alcohol fiber, 0.1-0.6 parts polyphosphate, 0.2-0.6 parts silane coupling agent, 0.1-0.3 parts latex, and 0.1-0.5 parts water-reducing agent.

[0010] Preferably, the composition comprises the following components in parts by weight: 100 parts phosphogypsum, 45-55 parts water, 0.7-2.5 parts calcium oxide, 0.3-0.5 parts polypropylene fiber, 0.1-0.2 parts polyvinyl alcohol fiber, 0.2-0.5 parts polyphosphate, 0.3-0.5 parts silane coupling agent, 0.1-0.2 parts latex, and 0.2-0.4 parts water-reducing agent.

[0011] Preferably, the polypropylene fiber has a length of 2-3 mm and a diameter of 10-15 μm.

[0012] Preferably, the polyvinyl alcohol fiber has a length of 2-3 mm and a diameter of 10-15 μm.

[0013] Preferably, the polyphosphate includes one or more of sodium tripolyphosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate.

[0014] Preferably, the silane coupling agent is a silane coupling agent containing a methacryloyloxy group.

[0015] Preferably, the water-reducing agent is a polycarboxylate-based water-reducing agent.

[0016] Preferably, the latex is polyvinyl alcohol latex.

[0017] The present invention also provides a plaster mold, which is obtained by molding the fiber-reinforced plaster composite material described in the above technical solution.

[0018] This invention provides a fiber-reinforced gypsum composite material comprising the following components in parts by weight: 100 parts phosphogypsum, 45-60 parts water, 0.5-3.5 parts calcium oxide, 0.2-0.6 parts polypropylene fiber, 0.1-0.3 parts polyvinyl alcohol fiber, 0.1-0.6 parts polyphosphate, 0.2-0.6 parts silane coupling agent, 0.1-0.3 parts latex, and 0.1-0.5 parts water-reducing agent. In this invention, polypropylene fibers and polyvinyl alcohol fibers work synergistically to optimize the force transmission path and improve the crack resistance of the matrix. Polyphosphates, under alkaline conditions, can be effectively adsorbed onto the fiber surface, exhibiting electronegativity and increasing electrostatic repulsion. Simultaneously, this enhances the adsorption performance of electronegative phosphate on the gypsum matrix, improving adhesion and thus significantly improving fiber dispersibility and bonding strength with the matrix. The latex is coupled using a silane coupling agent, further improving the bonding strength between the fibers and the gypsum matrix, fully utilizing the bridging effect of the fibers, and improving crack resistance. The water-reducing agent effectively lowers the water-cement ratio and increases matrix strength, ultimately resulting in gypsum molds prepared from the fiber-reinforced gypsum composite material provided by this invention exhibiting excellent crack resistance and breakage resistance. Detailed Implementation

[0019] This invention provides a fiber-reinforced gypsum composite material, comprising the following components in parts by weight:

[0020] The ingredients are: 100 parts phosphogypsum, 45-60 parts water, 0.5-3.5 parts calcium oxide, 0.2-0.6 parts polypropylene fiber, 0.1-0.3 parts polyvinyl alcohol fiber, 0.1-0.6 parts polyphosphate, 0.2-0.6 parts silane coupling agent, 0.1-0.3 parts latex, and 0.1-0.5 parts water-reducing agent.

[0021] In this invention, unless otherwise specified, all components are commercially available products well known to those skilled in the art.

[0022] The fiber-reinforced gypsum composite material provided by the present invention comprises 100 parts of phosphogypsum by weight.

[0023] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material comprises 45-60 parts of water, more preferably 45-55 parts, and even more preferably 50-52 parts. In this invention, the water is preferably tap water.

[0024] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material includes 0.5 to 3.5 parts of calcium oxide, more preferably 0.7 to 2.5 parts, and even more preferably 1.0 to 2.0 parts. In this invention, the calcium oxide can adjust the pH value of the phosphogypsum to 8 to 10, and can effectively remove harmful impurities such as soluble phosphorus and soluble fluorine, thereby improving the quality and performance of the phosphogypsum.

[0025] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material comprises 0.2 to 0.6 parts of polypropylene fiber, more preferably 0.3 to 0.5 parts, and even more preferably 0.4 to 0.5 parts. In this invention, the length of the polypropylene fiber is preferably 2 to 3 mm, and the diameter is preferably 10 to 15 μm. In this invention, the density of the polypropylene fiber is preferably 0.9 g / cm³. 3 The elastic modulus is preferably 3-5 GPa, and the tensile limit is preferably 6-10%.

[0026] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material comprises 0.1 to 0.3 parts, more preferably 0.1 to 0.2 parts, of polyvinyl alcohol fiber. In this invention, the length of the polyvinyl alcohol fiber is preferably 2 to 3 mm, and the diameter is preferably 10 to 15 μm. In this invention, the density of the polyvinyl alcohol is preferably 1.3 g / cm³. 3 The elastic modulus is preferably 35-40 GPa, and the tensile limit is preferably 10-15%.

[0027] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material comprises 0.1 to 0.6 parts of polyphosphate, more preferably 0.2 to 0.5 parts, and even more preferably 0.3 to 0.4 parts. In this invention, the polyphosphate preferably comprises one or more of sodium tripolyphosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate, more preferably sodium hexametaphosphate. In this invention, the sodium hexametaphosphate is preferably sodium hexametaphosphate produced by Beijing Kangpu Huiwei Technology Co., Ltd.

[0028] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material includes 0.2 to 0.6 parts of silane coupling agent, more preferably 0.3 to 0.5 parts, and even more preferably 0.3 to 0.4 parts. In this invention, the purity of the silane coupling agent is preferably ≥98.5%. In this invention, the silane coupling agent is preferably a silane coupling agent containing a methacryloxy group, more preferably KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd. or UP-573 silane coupling agent produced by Nanjing Youpu Chemical Co., Ltd.

[0029] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material comprises 0.1 to 0.3 parts of latex, more preferably 0.1 to 0.2 parts. In this invention, the latex preferably comprises polyvinyl alcohol latex. In this invention, the non-volatile content of the polyvinyl alcohol latex is preferably ≥98%, and the tensile strength is preferably 5.2 MPa.

[0030] Based on the mass fraction of the phosphogypsum, the fiber-reinforced gypsum composite material includes 0.1 to 0.5 parts of a water-reducing agent, more preferably 0.2 to 0.4 parts. In this invention, the water-reducing agent preferably includes a polycarboxylate-based water-reducing agent. In this invention, the water reduction rate of the polycarboxylate-based water-reducing agent is preferably 40%, and the pH value is preferably 6.5 to 8.5. In this invention, the polycarboxylate water-reducing agent is preferably a product manufactured by BASF, model number... 4930F polycarboxylate superplasticizer.

[0031] In this invention, the pH value of the fiber-reinforced gypsum composite material is preferably 9 to 10.

[0032] The present invention does not impose any special limitations on the preparation method of the fiber-reinforced gypsum composite material; the raw materials contained herein can be mixed evenly directly.

[0033] The present invention also provides a plaster mold, which is obtained by molding the fiber-reinforced plaster composite material described in the above technical solution.

[0034] In this invention, the preparation of the plaster mold preferably includes the following steps;

[0035] The fiber-reinforced gypsum composite material is placed in a gypsum mold forming device, and molding and demolding are performed sequentially to obtain the gypsum mold. This invention does not impose any special limitations on the molding and demolding process; any process well-known to those skilled in the art can be used.

[0036] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a fiber-reinforced gypsum composite material and a gypsum mold provided by the present invention, should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1

[0038] Materials: 100 parts phosphogypsum, 45 parts water, 0.5 parts calcium oxide, 0.2 parts polypropylene fiber, 0.1 parts polyvinyl alcohol fiber, 0.1 parts sodium hexametaphosphate, 0.2 parts silane coupling agent, 0.1 parts latex, and 0.1 parts water-reducing agent;

[0039] The polypropylene fibers have a diameter of 12 μm, a length of 2 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 5 GPa and the tensile limit is 10%.

[0040] The polyvinyl alcohol fibers have a diameter of 15 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 40 GPa and the tensile limit is 13%.

[0041] The silane coupling agent is KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd.

[0042] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0043] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0044] Example 2

[0045] Materials: 100 parts phosphogypsum, 60 parts water, 3.5 parts calcium oxide, 0.6 parts polypropylene fiber, 0.3 parts polyvinyl alcohol fiber, 0.6 parts sodium hexametaphosphate, 0.6 parts silane coupling agent, 0.3 parts latex, and 0.5 parts water-reducing agent;

[0046] The polypropylene fibers have a diameter of 10 μm, a length of 3 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 3 GPa and the tensile limit is 7%.

[0047] The polyvinyl alcohol fibers have a diameter of 12 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 35 GPa and the tensile limit is 15%.

[0048] The silane coupling agent is UP-573 silane coupling agent produced by Nanjing Youpu Chemical Co., Ltd.

[0049] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0050] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0051] Example 3

[0052] Materials: 100 parts phosphogypsum, 55 parts water, 1.5 parts calcium oxide, 0.5 parts polypropylene fiber, 0.2 parts polyvinyl alcohol fiber, 0.4 parts sodium hexametaphosphate, 0.3 parts silane coupling agent, 0.2 parts latex, and 0.3 parts water-reducing agent;

[0053] The polypropylene fibers have a diameter of 13 μm, a length of 2 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 4 GPa and the tensile limit is 8%.

[0054] The polyvinyl alcohol fibers have a diameter of 14 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 37 GPa and the tensile limit is 13%.

[0055] The silane coupling agent is UP-573 silane coupling agent produced by Nanjing Youpu Chemical Co., Ltd.

[0056] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0057] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0058] Example 4

[0059] Materials: 100 parts phosphogypsum, 48 parts water, 2.4 parts calcium oxide, 0.5 parts polypropylene fiber, 0.2 parts polyvinyl alcohol fiber, 0.2 parts sodium hexametaphosphate, 0.5 parts silane coupling agent, 0.3 parts latex, and 0.3 parts water-reducing agent;

[0060] The polypropylene fibers have a diameter of 11 μm, a length of 3 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 5 GPa and the tensile limit is 9%.

[0061] The polyvinyl alcohol fibers have a diameter of 13 μm, a length of 2 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 39 GPa and the tensile limit is 14%.

[0062] The silane coupling agent is UP-573 silane coupling agent produced by Nanjing Youpu Chemical Co., Ltd.

[0063] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0064] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0065] Example 5

[0066] Materials: 100 parts phosphogypsum, 55 parts water, 0.9 parts calcium oxide, 0.4 parts polypropylene fiber, 0.2 parts polyvinyl alcohol fiber, 0.5 parts sodium hexametaphosphate, 0.3 parts silane coupling agent, 0.3 parts latex, and 0.2 parts water-reducing agent;

[0067] The polypropylene fibers have a diameter of 14 μm, a length of 3 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 3 GPa and the tensile limit is 6%.

[0068] The polyvinyl alcohol fibers have a diameter of 12 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3The elastic modulus is 36 GPa and the tensile limit is 12%.

[0069] The silane coupling agent is KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd.

[0070] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0071] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0072] Comparative Example 1

[0073] Materials: 100 parts phosphogypsum, 45 parts water, 0.5 parts calcium oxide, 0.3 parts polypropylene fiber, 0.1 parts sodium hexametaphosphate, 0.2 parts silane coupling agent, 0.1 parts latex, and 0.1 parts water-reducing agent;

[0074] The polypropylene fibers have a diameter of 12 μm, a length of 2 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 5 GPa and the tensile limit is 10%.

[0075] The silane coupling agent is KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd.

[0076] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0077] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0078] Comparative Example 2

[0079] Materials: 100 parts phosphogypsum, 45 parts water, 0.5 parts calcium oxide, 0.3 parts polyvinyl alcohol fiber, 0.1 parts sodium hexametaphosphate, 0.2 parts silane coupling agent, 0.1 parts latex, and 0.1 parts water-reducing agent;

[0080] The polyvinyl alcohol fibers have a diameter of 15 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 40 GPa and the tensile limit is 13%.

[0081] The silane coupling agent is type KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd.

[0082] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0083] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0084] Comparative Example 3

[0085] Materials: 100 parts phosphogypsum, 45 parts water, 0.2 parts polypropylene fiber, 0.1 parts polyvinyl alcohol fiber, 0.2 parts silane coupling agent, 0.1 parts latex, and 0.1 parts water-reducing agent;

[0086] The polypropylene fibers have a diameter of 12 μm, a length of 2 mm, and a density of 0.9 g / cm³. 3 The elastic modulus is 5 GPa and the tensile limit is 10%.

[0087] The polyvinyl alcohol fibers have a diameter of 15 μm, a length of 3 mm, and a density of 1.3 g / cm³. 3 The elastic modulus is 40 GPa and the tensile limit is 13%.

[0088] The silane coupling agent is KH-670 silane coupling agent produced by Zhejiang Woxingman New Material Technology Co., Ltd.

[0089] The latex is polyvinyl alcohol latex with a non-volatile content of ≥98% and a tensile strength of 5.2 MPa;

[0090] The water-reducing agent is manufactured by BASF and is of the following type: 4930F polycarboxylate superplasticizer.

[0091] Application examples

[0092] The fiber-reinforced gypsum composite materials obtained in Examples 1-5 and Comparative Examples 1-3 were placed in gypsum molds and then molded and demolded in sequence to obtain gypsum molds.

[0093] Performance testing

[0094] Performance testing was performed on the plaster molds obtained from the corresponding use cases;

[0095] The methods for determining the compressive load and vibration impact resistance of the bottom surface refer to the standard JC / T 2472-2018 "Gypsum Board for Cast-in-place Hollow Concrete Floor Slab Structures";

[0096] The load-bearing capacity testing methods for the top and sides refer to standard JC / T 952-2014 "Infill Material for Cast-in-place Hollow Concrete Floor Slab Structures";

[0097] The softening coefficient test method refers to standard JC / T 698-2010 "Gypsum Blocks";

[0098] The test results are shown in Table 1.

[0099] Table 1. Performance test results of the plaster molds obtained in Examples 1-5 and Comparative Examples 1-3.

[0100] Bottom compressive load / kN Vibration and shock resistant Top and side load-bearing capacity Softening coefficient Example 1 9 No cracks No cracks, no damage 0.65 Example 2 15 No cracks No cracks, no damage 0.72 Example 3 12 No cracks No cracks, no damage 0.62 Example 4 8 No cracks No cracks, no damage 0.76 Example 5 13 No cracks No cracks, no damage 0.69 Comparative Example 1 7 Obvious cracks appeared Cracks, damage 0.51 Comparative Example 2 8 Tiny cracks appeared Cracked, but not broken 0.58 Comparative Example 3 6 Obvious cracks appeared Cracks, damage 0.55

[0101] As can be seen from Table 1, the gypsum mold prepared from the fiber-reinforced gypsum composite material provided by the present invention has good crack resistance and damage resistance.

[0102] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A plaster mold, characterized in that, It is obtained by molding fiber-reinforced gypsum composite material; The fiber-reinforced gypsum composite material, by mass parts, comprises: The ingredients are: 100 parts phosphogypsum, 45-60 parts water, 0.5-3.5 parts calcium oxide, 0.2-0.6 parts polypropylene fiber, 0.1-0.3 parts polyvinyl alcohol fiber, 0.1-0.6 parts polyphosphate, 0.2-0.6 parts silane coupling agent, 0.1-0.3 parts latex, and 0.1-0.5 parts water-reducing agent. The water-reducing agent is a polycarboxylate-based water-reducing agent; The polypropylene fiber has a length of 2-3 mm; the polyvinyl alcohol fiber has a length of 2-3 mm.

2. The plaster mold according to claim 1, characterized in that, The components, by weight, are: 100 parts phosphogypsum, 45-55 parts water, 0.7-2.5 parts calcium oxide, 0.3-0.5 parts polypropylene fiber, 0.1-0.2 parts polyvinyl alcohol fiber, 0.2-0.5 parts polyphosphate, 0.3-0.5 parts silane coupling agent, 0.1-0.2 parts latex, and 0.2-0.4 parts water-reducing agent.

3. The plaster mold according to claim 1 or 2, characterized in that, The diameter of the polypropylene fiber is 10-15 μm.

4. The plaster mold according to claim 1 or 2, characterized in that, The diameter of the polyvinyl alcohol fiber is 10-15 μm.

5. The plaster mold box according to claim 1, characterized in that, The polyphosphate includes one or more of sodium tripolyphosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate.

6. The plaster mold according to claim 1, characterized in that, The silane coupling agent is a silane coupling agent containing a methacryloyloxy group.

7. The plaster mold according to claim 1 or 2, characterized in that, The latex is polyvinyl alcohol latex.