Measurement method of sand content in concrete and application of sand based on methylene blue value parameters

Abstract

A method for measuring the mud content of sand used in concrete based on methylene blue value parameters and sand application, the steps are: the mud content of the sand to be measured α=, MB D Set to the MB value of the sand to be tested, MB B Set to the MB value of standard sand, MB J The MB value of the reference sand is set. The mud content has a significant effect on the fluidity of the mortar. The application calculates the mud content of the sand to be tested through the MB values ​​of the sand to be tested, the standard sand and the reference sand, and then makes a quantitative judgment on whether the mud content of the sand to be tested is qualified. A general method for judging the qualification of the mud content of sand is proposed, which can be used for both river sand and artificial sand. The data is intuitive and reliable, and the method is simple to operate. It can play an important guiding role in the application of the sand to be tested in precast concrete.

Description

Technical Field

[0001] The invention relates to a method for measuring the mud content of sand used in concrete and the application of the sand, in particular to a method for measuring the mud content of sand used in concrete based on a methylene blue value parameter and the application of the sand. Background Art

[0002] Concrete is a building material made by mixing raw materials such as cement, sand, stone, water and admixtures. It is the largest and most widely used material in today's construction. Among them, the mud content of concrete sand has a significant impact on the mixing state of concrete and the strength after hardening. Too high mud content can easily lead to an increase in the water requirement for concrete mixing, and at the same time it can easily lead to a decrease in the pumping performance of concrete, which in turn leads to a decrease in concrete strength and affects the quality of the building. Concrete sand is inevitably easy to mix with soil due to its source and process reasons. When the mud content is low, its effect on the performance of concrete is small, but when the mud content is high, its impact is significant.

[0003] In the prior art, there are two methods for detecting the mud content of sand as described in JGJ52-2006 "Standard for the Quality and Inspection Methods of Sand and Stone for Ordinary Concrete". One method is to determine that the part under the 0.08mm sieve in the sand mud content test standard method is mud; the other method is to determine that the main content is stone powder when the MB value is <1.4 by the methylene blue method, and the main content is mud powder when the MB value is ≥1.4. It is mainly used to detect artificial sand.

[0004] The above two methods are only qualitative judgments, not quantitative judgments, and have limited guiding role in their application in concrete. The prior art does not yet have a quantitative method to determine whether the mud content is qualified and whether it can be applied to concrete of different grades.

[0005] Based on the technical briefing document provided by the applicant on May 18, 2022, which solves practical technical problems in the work process, and the existing technical problems, technical features and technical effects in similar patent documents and background technologies obtained through retrieval, the technical application scheme of the present invention was made. Summary of the invention

[0006] The object of the present invention is a method for measuring the sand content of concrete based on the methylene blue value parameter.

[0007] The object of the present invention is a sand application based on the methylene blue value parameter.

[0008] In order to overcome the above technical shortcomings, the purpose of the present invention is to provide a method for measuring the mud content of sand in concrete based on methylene blue value parameters and sand application, thereby achieving quantitative measurement and determination of the mud content of the sand to be measured.

[0009] To achieve the above object, the technical solution adopted by the present invention is: a method for measuring the mud content of sand used in concrete based on the methylene blue value parameter, the steps are: the mud content of the sand to be measured α = , M.B. D Set to the MB value of the sand to be tested, MB B Set to the MB value of standard sand, MB J Set to the MB value of the base sand.

[0010] The technical effect of the above technical solution is: it creates a reference value for the mud content of sand, and digitizes the performance matching between the performance of concrete and the mud content of sand.

[0011] Since the mud content α of the sand is designed, the mud content has a significant impact on the fluidity of the mortar. This application calculates the mud content of the sand to be tested through the MB values ​​of the sand to be tested, standard sand and benchmark sand, and then makes a quantitative judgment on whether the mud content of the sand to be tested is qualified. A general method for judging the qualification of the mud content of sand is proposed, which can be used for both river sand and artificial sand. The data is intuitive and reliable, and the method is simple to operate. It can play an important guiding role in the application of the sand to be tested in precast concrete.

[0012] The present invention has been designed, and the steps are:

[0013] 1. According to the methylene blue method, the MB value of the sand to be tested, the standard sand and the reference sand is measured to obtain MB D 、MB B and MB J ,

[0014] Second, according to α= , calculate the mud content α of the sand to be tested,

[0015] 3. When the mud content α≤5.0%, the mud content of the sand to be tested is qualified; when the mud content α>5.0%, the mud content of the sand to be tested is unqualified.

[0016] The technical effect of the above technical solution is to realize the numerical measurement and setting of the reference value of the mud content of the sand.

[0017] The present invention designs a method for preparing standard sand: the steps are:

[0018] 1. After washing the sand to be tested and drying it, weigh the sand to be tested with a weight of Ag, and sieve the sand to be tested through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. Weigh the sieve residue to obtain a weight value Bg, and weigh the undersize to obtain a weight value Cg. The weight percentage F1 of the sieve residue and the weight percentage F2 of the undersize are obtained by calculation. F1=B / A, F2=C / A,

[0019] 2. Grind a portion of the residue, and then sieve it through a 0.08 mm standard sieve to obtain an intermediate medium of the undersize with a particle diameter less than or equal to 0.08 mm. According to the weight percentage F2 of the undersize or the weight percentage F1 of the residue, mix the intermediate medium of the undersize with the residue to obtain standard sand.

[0020] The technical effect of the above technical solution is that: the preparation and setting of standard sand from the sand to be tested is realized, and the measurement accuracy of the reference value of the mud content of the sand is improved.

[0021] The present invention designs a method for preparing reference sand, wherein the steps are:

[0022] After washing the sand to be tested and drying it, the sand to be tested is screened through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. According to the reference mud content of 5%, the reference mud and the sieve residue are mixed to obtain the reference sand.

[0023] The present invention is designed to set the reference mud to have a fineness of less than 0.08 mm and a specific surface area of ​​475 m 2 / kg~525m 2 / kg of kaolin.

[0024] The technical effect of the above technical solution is that: the preparation of reference sand from the sand to be tested is realized, and the measurement accuracy of the reference value of the mud content in the sand is improved.

[0025] The present invention is designed to measure the sand mud content α of the standard mortar sample and the mortar sample to be tested at least twice to obtain an average value of the sand mud content α. When the average value of the sand mud content α is ≤5.0%, the sand mud content in the mortar sample to be tested is at a qualified value. When the average value of the sand mud content α is greater than 5.0%, the sand mud content in the mortar sample to be tested is at an unqualified value.

[0026] The technical effect of the above technical solution is to eliminate the influence of measurement error on the setting.

[0027] The present invention designs a sand application based on a methylene blue value parameter. When the mud content α of the sand is set to ≤2.0%, the sand to be tested can be used to prepare concrete with a grade of C60 or above; when the mud content α of the sand is set to 2.0%-≤3.0%, the sand to be tested can be used to prepare concrete with a grade of C30, C35, C40, C45, C50, and C55; when the mud content α of the sand is set to 3.0%-≤5.0%, the sand to be tested can be used to prepare concrete with a grade of C25 or below; when the mud content α of the sand is set to >5.0%, the sand cannot be used to prepare concrete.

[0028] The technical effect of the above technical solution is: a groundbreaking classification setting is made for the sand to be tested, thereby improving the corresponding concrete performance.

[0029] The technical effect of the present invention is that: compared with the prior art, the purpose of the present invention is to provide a method for determining the mud content of concrete sand, which can be quantitatively determined, has a wide range of applications, reliable data and has important guiding significance for application in concrete, and its application; first, the present application determines the MB value of the sand to be tested, standard sand and reference sand by the methylene blue method, and calculates the α value of the mud content of the sand to be tested, and quantitatively determines whether the mud content of the sand to be tested is qualified, and then proposes a general method for determining the qualified mud content of sand, which has a wide range of applications and can be used for both river sand and artificial sand. The data is intuitive and reliable, and the method is simple to operate; secondly, based on the result of the quantitative determination of the mud content, the present application proposes an application scheme of the above-mentioned sand mud content qualified determination method in concrete of different grades, which has important guiding significance for the application of the sand to be tested in precast concrete, and can effectively avoid the influence of the mud content on the quality of concrete of different grades, thereby improving the concrete preparation efficiency and the overall quality of concrete.

[0030] In the present technical scheme, the mud content α of sand is an important technical feature. In the technical field of the measurement method of the mud content of sand used in concrete based on the methylene blue value parameter and the application of sand, it has novelty, creativity and practicality. The terms in the present technical scheme can be explained and understood using the patent literature in this technical field. DETAILED DESCRIPTION

[0031] According to the Examination Guidelines, terms such as “having”, “including” and “comprising” used in the present invention should be understood as not dispensing with the existence or addition of one or more other elements or combinations thereof.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship generally shown, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. In addition, unless otherwise specified, the equipment and materials used in the following examples are commercially available. If the processing conditions are not clearly stated, please refer to the purchased product manual or proceed according to conventional methods in the art.

[0035] The present invention is further described below in conjunction with examples. The following examples are intended to illustrate the present invention rather than to further limit the present invention.

[0036] A method for measuring the sand content of concrete based on methylene blue value parameters, the steps of which are:

[0037] 1. According to the methylene blue method, the MB value of the sand to be tested, the standard sand and the reference sand is measured to obtain MB D 、MB B and MB J ,

[0038] Second, according to α= , calculate the mud content α of the sand to be tested,

[0039] 3. When the mud content α≤5.0%, the mud content of the sand to be tested is qualified; when the mud content α>5.0%, the mud content of the sand to be tested is unqualified.

[0040] In this embodiment, MB D Set to the MB value of the sand to be tested, MB B Set to the MB value of standard sand, MB J Set to the MB value of the base sand.

[0041] In this embodiment, the preparation method of standard sand is as follows:

[0042] 1. After washing the sand to be tested and drying it, weigh the sand to be tested with a weight of Ag, and sieve the sand to be tested through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. Weigh the sieve residue to obtain a weight value Bg, and weigh the undersize to obtain a weight value Cg. The weight percentage F1 of the sieve residue and the weight percentage F2 of the undersize are obtained by calculation. F1=B / A, F2=C / A,

[0043] 2. Grind a portion of the residue, and then sieve it through a 0.08 mm standard sieve to obtain an intermediate medium of the undersize with a particle diameter less than or equal to 0.08 mm. According to the weight percentage F2 of the undersize or the weight percentage F1 of the residue, mix the intermediate medium of the undersize with the residue to obtain standard sand.

[0044] In this embodiment, the preparation method of the reference sand is as follows:

[0045] After washing the sand to be tested and drying it, the sand to be tested is screened through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. According to the reference mud content of 5%, the reference mud and the sieve residue are mixed to obtain the reference sand.

[0046] In this embodiment, the reference mud is set to have a fineness of less than 0.08 mm and a specific surface area of ​​475 m 2 / kg~525m 2 / kg of kaolin.

[0047] In this embodiment, the sand mud content α of the standard mortar sample and the mortar sample to be tested is measured at least twice to obtain an average value of the sand mud content α. When the average value of the sand mud content α is ≤5.0%, the sand mud content in the mortar sample to be tested is at a qualified value. When the average value of the sand mud content α is >5.0%, the sand mud content in the mortar sample to be tested is at an unqualified value.

[0048] A sand application based on a methylene blue value parameter. When the mud content α of the sand is set to ≤2.0%, the sand to be tested can be used to prepare concrete of grades C60 and above; when the mud content α of the sand is set to 2.0%-≤3.0%, the sand to be tested can be used to prepare concrete of grades C30, C35, C40, C45, C50, and C55; when the mud content α of the sand is set to 3.0%-≤5.0%, the sand to be tested can be used to prepare concrete of grades C25 and below; when the mud content α of the sand is set to >5.0%, it cannot be used to prepare concrete.

[0049] The test data of each embodiment are as follows:

[0050] In Example 1, the mud content of the sand to be tested is α≤2.0%, and the mortar test is carried out according to the current national standard, and concrete with the same mix ratio and grade of C60 is prepared;

[0051] In Example 2, the mud content of the sand to be tested is 2.0%<α≤3.0%, and the mortar test is carried out according to the current national standard, and concrete with the same mix ratio and grade C30 is prepared;

[0052] In Example 3, the mud content of the sand to be tested is 3.0%<α≤5.0%, and the mortar test is carried out according to the current national standard, and concrete with the same mix ratio and grade C25 is prepared;

[0053] In Example 4, the mud content α of the sand to be tested is greater than 5.0%, a mortar test is carried out according to the current national standard, and concrete with a C25 grade and the same mix ratio is prepared.

[0054] The test data of Examples 1 to 4 are as follows:

[0055] Mud content of sand to be tested α 28-day strength of mortar 28-day strength of C60 concrete with the same raw materials and proportion river sand 1 1.8% 49.2MPa 68.5MPa Artificial sand 1 1.9% 48.6MPa 67.9MPa

[0056] The cement used in the embodiment is 42.5 silicate cement. It can be seen from the mortar strength and concrete strength that the determination method of the present invention has a good correlation with the mechanical properties of mortar and concrete, the determination result is accurate, and the guiding significance is significant.

[0057] Mud content of sand to be tested α 28-day strength of mortar 28-day strength of C30 concrete with the same raw materials and proportion river sand 2 2.5% 43.5MPa 37.3MPa Artificial sand 2 2.4% 43.6MPa 37.5MPa

[0058] The cement used in the embodiment is 32.5 silicate cement. It can be seen from the mortar strength and concrete strength that the determination method of the present invention has a good correlation with the mechanical properties of mortar and concrete, the determination result is accurate, and the guiding significance is significant.

[0059] Mud content of sand to be tested α 28-day strength of mortar 28-day strength of C25 concrete with the same raw materials and proportion river sand 3 4.8% 38.5MPa 28.4MPa Artificial sand 3 4.7% 39.6MPa 29.5MPa

[0060] The cement used in the embodiment is 32.5 silicate cement. It can be seen from the mortar strength and concrete strength that the determination method of the present invention has a good correlation with the mechanical properties of mortar and concrete, the determination result is accurate, and the guiding significance is significant.

[0061] Mud content of sand to be tested α 28-day strength of mortar 28-day strength of C25 concrete with the same raw materials and proportion river sand 4 5.8% 31.8MPa 21.9MPa Artificial sand 4 5.6% 32.0MPa 22.6MPa

[0062] The cement used in the embodiment is 32.5 silicate cement. It can be seen from the mortar strength and concrete strength that the determination method of the present invention has a good correlation with the mechanical properties of mortar and concrete. When the mud content α of the sand to be tested is greater than 5%, the concrete strength does not reach the grade value, and the sand to be tested cannot be used for concrete preparation. The determination result of this application is accurate and has significant guiding significance.

[0063] The present invention has the following characteristics:

[0064] 1. Since the mud content α of the sand is designed, the mud content has a significant impact on the fluidity of the mortar. This application calculates the mud content of the sand to be tested through the MB values ​​of the sand to be tested, standard sand, and reference sand, and then quantitatively determines whether the mud content of the sand to be tested is qualified. A general method for determining the qualification of the mud content of sand is proposed, which can be used for both river sand and artificial sand. The data is intuitive and reliable, and the method is simple to operate. It can play an important guiding role in the application of the sand to be tested in precast concrete.

[0065] 2. Due to the design of MB values ​​of the sand to be tested, standard sand and reference sand, the standard comparison setting of the sand to be tested is realized.

[0066] 3. Due to the design of the sieve residue, similar performance settings are achieved for standard sand, reference sand and the sand to be tested.

[0067] 4. Since the design limits the numerical range of the structural shape, the numerical range is the technical feature in the technical solution of the present invention, rather than a technical feature calculated by a formula or obtained through a limited number of tests. Tests have shown that the technical feature of this numerical range has achieved good technical effects.

[0068] 5. Due to the design of the technical features of the present invention, the effects of the individual and combined technical features have been shown through experiments to have various performance indicators of the present invention that are at least 1.7 times the existing performance indicators, and have been evaluated to have good market value.

[0069] There are other technical features that are the same or similar to the mud content α of the sand used, which are all embodiments of the present invention, and the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to meet the requirements of the Patent Law, Patent Implementation Rules and Examination Guidelines, all possible combinations of the technical features in the above-mentioned embodiments will no longer be described.

[0070] The above embodiment is only one implementation form of the method for measuring the mud content of sand in concrete based on the methylene blue value parameter and the application of sand provided by the present invention. Other variations of the scheme provided by the present invention, adding or reducing the components or steps therein, or applying the present invention to other technical fields close to the present invention, all belong to the protection scope of the present invention.

Claims

1. A method for measuring the sand content of concrete based on methylene blue value parameters, characterized in that the steps are: Mud content of sand to be tested MB D is set as the MB value of the sand to be tested, MB B is set as the MB value of the standard sand, and MB J is set as the MB value of the reference sand. The steps are:

1. According to the methylene blue method, the MB values ​​of the sand to be tested, the standard sand and the reference sand are measured to obtain MB D , MB B and MB J .

2. Based on , calculate the mud content α of the sand to be tested, 3. When the mud content α≤5.0%, the mud content of the sand to be tested is qualified; when the mud content α>5.0%, the mud content of the sand to be tested is unqualified. Preparation method of standard sand: The steps are:

1. After washing the sand to be tested and drying it, weigh the sand to be tested with a weight of Ag, and sieve the sand to be tested through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. Weigh the sieve residue to obtain a weight value Bg, and weigh the undersize to obtain a weight value Cg. The weight percentage F1 of the sieve residue and the weight percentage F2 of the undersize are obtained by calculation. F1=B / A, F2=C / A, 2. Grind a portion of the residue, and then sieve it through a 0.08 mm standard sieve to obtain an intermediate medium of the undersize with a particle diameter of less than or equal to 0.08 mm. According to the weight percentage F2 of the undersize or the weight percentage F1 of the residue, mix the intermediate medium of the undersize with the residue to obtain standard sand. Preparation method of reference sand: The steps are: After washing the sand to be tested and drying it, the sand to be tested is sieved through a 0.08mm standard sieve to obtain the sieve residue with a particle diameter greater than 0.08mm and the sieve undersize with a particle diameter less than or equal to 0.08mm. According to the reference mud content of 5%, the reference mud and the sieve residue are mixed to obtain the reference sand. The reference mud is set to be kaolin with a fineness of less than 0.08 mm and a specific surface area of ​​475 m 2 / kg to 525 m 2 / kg.

2. The method for measuring the sand content of concrete based on the methylene blue value parameter according to claim 1 is characterized in that: The sand mud content α of the standard mortar sample and the mortar sample to be tested is measured at least twice to obtain the average value of the sand mud content α. When the average value of the sand mud content α is ≤5.0%, the sand mud content in the mortar sample to be tested is at a qualified value; when the average value of the sand mud content α is >5.0%, the sand mud content in the mortar sample to be tested is at an unqualified value.

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