阅读说明：本技术 一种半柔性路面水泥胶浆灌注饱和度的确定方法 (Method for determining grouting saturation of cement mortar of semi-flexible pavement ) 是由 刘黎萍 李佳豪 孙立军 程怀磊 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种半柔性路面水泥胶浆灌注饱和度的确定方法,所述方法为：步骤S1、成型基体沥青混合料试件,脱模后测量试件的质量和体积；步骤S2、测量试件的水中质量,计算基体沥青混合料的连通空隙率；步骤S3、成型水泥胶浆圆柱体试件,养生脱模后测量试件的质量和体积,计算试件的密度；步骤S4、灌注水泥胶浆成型半柔性路面材料试件,养生脱模后测试试件的质量,计算半柔性路面材料试件的灌注饱和度。本发明解决了现有半柔性路面灌注率指标确定方法存在较大误差的问题。(The invention discloses a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which comprises the following steps: s1, forming a matrix asphalt mixture test piece, and measuring the mass and the volume of the test piece after demolding; s2, measuring the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture; s3, forming a cement mortar cylindrical test piece, measuring the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece; and S4, pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece. The method solves the problem that the existing method for determining the perfusion rate index of the semi-flexible pavement has large errors.)

1. The method for determining the perfusion saturation of the cement mortar on the semi-flexible pavement is characterized by comprising the following steps:

s1, forming a matrix asphalt mixture test piece, and measuring the mass and the volume of the test piece after demolding;

s2, measuring the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

s3, forming a cement mortar cylindrical test piece, measuring the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece;

and S4, pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece.

2. The method for determining the grouting saturation of the cement mortar for the semi-flexible pavement according to claim 1, wherein in step S1, the matrix asphalt mixture is molded by a marshall compaction method, floating grains on the surface of the test piece are removed when the aerial mass of the test piece is measured, the marshall test piece is dried to constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper to be accurate to 0.1mm, the average value of the measurement results of the upper and lower sections is selected when the diameter is measured, and the average value of four cross-symmetric measurements is taken for the thickness.

3. The method for determining the grouting saturation of the cement mortar for the semi-flexible pavement according to claim 1, wherein in step S2, the water temperature of the overflow water tank is kept at 25 ℃ ± 0.5 ℃, the basket is hung and immersed in the overflow water tank, the water level is adjusted, the balance is leveled and zeroed, the test piece is placed in the basket and immersed for about 3-5 min, and the mass in water is measured after the balance is stabilized.

4. The method for determining the grouting saturation of the cement mortar for the semi-flexible pavement according to claim 1, wherein in the step S2, the method for calculating the communication porosity comprises the following steps:

in the formula: VV_c-interconnected porosity%;

V_mmm volume of mix and closed voids³；

m_a-the aerial mass g of the dried specimen;

m_w-the underwater mass g of the test piece;

ρ_wdensity of water at-25 deg.C, 0.9971g/cm³；

V-volume mm of the test piece³；

The test results should be expressed as an average of the interconnected porosity of a set of test pieces to the nearest 0.1%.

5. The method for determining the grouting saturation of cement mortar for semi-flexible pavement according to claim 1, wherein in step S3, the cement test piece is prepared by using an iron sleeve used in a marshall compaction method, the test piece is left to stand for 24 hours after being poured, the test piece is demoulded, the test piece is placed in a curing chamber with the temperature of 20 ℃ ± 3 ℃ and the humidity of more than or equal to 90% for curing for three days, when the air quality of the test piece is measured, the floating particles on the surface of the test piece are removed, the marshall test piece is dried to constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper to be accurate to 0.1mm, the average value of the measurement results of the upper and lower sections is selected when the diameter is measured, and the average value of four-time cross symmetry measurement is taken as the thickness.

6. The method for determining the grouting saturation of cement mortar for semi-flexible pavement according to claim 1, wherein in step S3, the calculation formula of cement mortar density is:

in the formula: rho_sDensity g/mm of Cement test pieces³；

m_s-mass g of cement test piece;

V_svolume mm of the Cement test piece³。

7. The method for determining the grouting saturation of cement mortar for semi-flexible pavement according to claim 1, wherein in step S4, the bottom and the side of the marshall test piece are tightly wrapped by a PET plastic plate and transparent adhesive tape paper before grouting, the side is 1-2 cm higher than the test piece for grouting, the mixed cement mortar is slowly poured along one side until the mortar is 1cm lower than the test piece, the mortar does not seep any more, the surface cement mortar is scraped by a scraper, after standing for 24 hours, the test piece is demoulded, placed in a curing chamber with the temperature of 20 ℃ ± 3 ℃ and the humidity of not less than 90% for curing for 3 days, the test piece is dried by an electric fan to constant weight, and the aerial quality of the marshall test piece after grouting is determined.

8. The method for determining the perfusion saturation of the cement mortar for the semi-flexible pavement according to claim 1, wherein in step S4, the perfusion saturation is calculated according to the following formula:

in the formula: v_c-volume mm of cement mortar poured³；

m'_aThe aerial mass g of the semi-flexible pavement material test piece;

m_athe aerial mass g of the matrix asphalt mixture test piece;

P_r-perfusion saturation;

the test results should be expressed as the average of the perfusion saturations of a set of test pieces to the nearest 0.1%.

Technical Field

The invention relates to the technical field of traffic road tests, in particular to a method for determining the grouting saturation of cement mortar on a semi-flexible pavement.

Background

The filling saturation is the percentage of the volume of the cement mortar filled into the matrix asphalt mixture to the volume of the communicated porosity, and represents the saturation degree in the semi-flexible pavement. Researches show that the filling saturation has great influence on the mechanical property of the filling type semi-flexible pavement material, and the higher the filling saturation is, the better the strength and the stability are.

The method for testing the perfusion rate of the semi-flexible pavement commonly used at present comprises the steps of firstly testing the communication porosity of a matrix asphalt mixture by adopting an underwater weight method, testing the communication porosity by adopting the underwater weight method after grouting and curing are finished, and obtaining the perfusion rate by adopting the difference value of two times of tests. Such a calculation of perfusion saturation can present a problem: perfusion saturation cannot reach 100% in theory. The filling saturation is used as an index for evaluating the actual filling effect of the cement mortar, and the degree of filling the communicated gaps when the cement mortar is filled is reflected, namely the relative size of the gaps between the cement mortar and the asphalt, and the theoretical maximum value of the filling saturation is 100%. Because the cement in the test piece has water absorption, when the connected porosity of the test piece after grouting is tested by a water-in-water gravity method, the volume of water absorbed by the cement can be also used as the volume of the connected porosity, and even if the cement mortar is completely filled in the connected porosity of the matrix asphalt mixture, the filling saturation cannot reach 100%.

Disclosure of Invention

Therefore, the invention provides a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which aims to solve the problem of large error in the existing method for determining the perfusion rate index of the semi-flexible pavement.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention discloses a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which comprises the following steps: s1, forming a matrix asphalt mixture test piece, and measuring the mass and the volume of the test piece after demolding;

s2, measuring the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

s3, forming a cement mortar cylindrical test piece, measuring the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece;

and S4, pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece.

Further, in step S1, the matrix asphalt mixture is molded by a marshall compaction method, when the aerial mass of the test piece is measured, the floating particles on the surface of the test piece are removed, the marshall test piece is dried to a constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper to be accurate to 0.1mm, the average value of the measurement results of the upper and lower sections is selected when the diameter is measured, and the average value of four-time cross symmetry measurement is taken as the thickness.

Further, in the step S2, the water temperature of the overflow water tank is kept at 25 ℃ ± 0.5 ℃, a mesh basket is hung, the overflow water tank is immersed, the water level is adjusted, the balance is leveled and reset, the test piece is placed in the mesh basket and immersed for about 3-5 min, and the mass in water is measured after the balance is stabilized.

Further, in step S2, the method for calculating the connected porosity includes:

in the formula: VV_c-interconnected porosity%;

V_mmm volume of mix and closed voids³；

m_a-the aerial mass g of the dried specimen;

m_w-the underwater mass g of the test piece;

ρ_wdensity of water at-25 deg.C, 0.9971g/cm³；

V-volume mm of the test piece³；

The test result is represented by the average value of the communication porosity of a group of test pieces, wherein the number of the group of test pieces is 3-6, and the accuracy is 0.1%.

Further, in the step S3, the cement test piece is prepared by using an iron sleeve used in a marshall compaction method, the test piece is placed for 24 hours after being poured, the test piece is demolded, the test piece is placed in a health preserving room with the temperature of 20 ℃ ± 3 ℃ and the humidity of more than or equal to 90% for health preserving for three days, when the aerial quality of the test piece is weighed, floating grains on the surface of the test piece are removed, the marshall test piece is dried to constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper and are accurate to 0.1mm, the average value of the measurement results of the upper section and the lower section is selected when the diameter is measured, and the average value of four times of cross symmetry measurement is taken as the thickness.

Further, in step S3, the cement mortar density calculation formula is:

in the formula: rho_sDensity g/mm of Cement test pieces³；

m_s-mass g of cement test piece;

V_svolume mm of the Cement test piece³。

Further, in the step S4, before grouting, the bottom and the side of the marshall test piece are tightly wrapped by a PET plastic plate and transparent adhesive tape paper, the side is 1-2 cm higher than the test piece for grouting, the mixed cement mortar is slowly poured along one side until the slurry is 1cm lower than the test piece, the slurry does not seep any more, the surface cement mortar is scraped off by a scraper, after standing for 24 hours, the test piece is demoulded, placed in a curing chamber with the temperature of 20 ℃ +/-3 ℃ and the humidity of not less than 90% for curing for 3 days, the test piece is dried by an electric fan to constant weight, and the aerial quality of the marshall test piece after grouting is measured.

Further, in step S4, the perfusion saturation is calculated according to the following formula:

in the formula: v_c-volume mm of cement mortar poured³；

m'_aThe aerial mass g of the semi-flexible pavement material test piece;

m_athe aerial mass g of the matrix asphalt mixture test piece;

P_r-perfusion saturation;

the test result is expressed by the average value of the perfusion saturation of a group of test pieces, wherein the number of the test pieces is 3-6, and the accuracy is 0.1%.

The invention has the following advantages:

the invention discloses a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which has high test precision, the perfusion rate index of the traditional method is used for testing the communication porosity of a test piece after grouting by a twice underwater gravity method and calculating the difference value to obtain the perfusion saturation, a closed volume can be formed between the cement and an asphalt interface after grouting, and the volume of water absorbed by the cement can be taken as the communication porosity volume, so that the test is inaccurate, and the test result is influenced; the method has the advantages that the mass of the test piece before and after grouting and the cement density are weighed to determine the grouting amount and calculate the grouting saturation, the influence of the closed volume between the cement and the asphalt interface and the cement water absorption is avoided, and the obtained result is more accurate;

the operation is more convenient, each test piece needs to be soaked in water for about 3-5 min when the water weight of the test piece after grouting is tested by the traditional method, the number is read after the balance is stabilized, and other tests can be carried out only after the test piece is dried to be constant weight after the test is finished, so that time and labor are wasted; the invention only needs to test the density of the cement mortar once, only needs to test the aerial quality of a test piece using the same proportion of cement mortar, does not need to test the water immersion, and can directly carry out other tests on the test piece after the test is finished.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

Fig. 1 is a flowchart of a method for determining a grouting saturation of a cement mortar for a semi-flexible pavement according to an embodiment of the present invention;

FIG. 2 is a graph comparing the test results of the present invention and the conventional method provided in the embodiment of the present invention;

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1, the embodiment discloses a method for determining the grouting saturation of cement mortar for a semi-flexible pavement, where the method includes:

step 1, forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

s2, measuring the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

s3, adopting a certain brand of finished cement mortar, wherein the water-cement ratio is 0.42, the fluidity is 15.3S, forming a cement mortar cylindrical test piece, measuring the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece;

and S4, pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece.

In step S1, the matrix asphalt mixture is molded by a marshall compaction method, when the aerial mass of the test piece is measured, the floating particles on the surface of the test piece are removed, the marshall test piece is dried to constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper to be accurate to 0.1mm, the average value of the measurement results of the upper and lower sections is selected when the diameter is measured, and the average value of the four-time cross symmetry measurement is taken as the thickness.

The Marshall compaction method comprises the following steps: uniformly weighing the mixed asphalt mixture by the amount of about 1200g/4050g required by a test piece, and calculating and multiplying the standard size of the test piece by 1.03 to obtain the required quantity of the mixture when the density of the asphalt mixture is known;

in the manufacturing process of the test piece, in order to prevent the temperature of the mixture from dropping, the test piece is placed in an oven with a tray for heat preservation. Taking out the preheated test mould and sleeve from the oven, wiping the sleeve, base and bottom surface of the compaction hammer with cotton yarn stained with little butter, mounting the test mould on the base, padding a piece of round paper with small oil absorption, shoveling the mixed material into the test mould with a small shovel from four directions according to a quartering method, and inserting and tamping the mixed material for 15 times along the periphery and 10 times in the middle by using an slotting tool or a large screwdriver. And leveling the surface of the asphalt mixture into a convex arc surface after the inserting and tamping. Adding the mixture into a large Marshall test piece twice, wherein the number of times of inserting and tamping each time is the same as that of adding and tamping each time;

inserting a thermometer to the position near the center of the mixture, and checking the temperature of the mixture;

after the temperature of the mixture meets the required compaction temperature, the test mould and the base are together placed on a compaction table to be fixed, a piece of round paper with low oil absorption is padded on the loaded mixture, then a compaction head provided with a compaction instrument hammer and a guide rod is inserted into the test mould, and the compaction instrument is started to start the experiment;

in step S2, keeping the water temperature of the overflow water tank at 25 +/-0.5 ℃, hanging a mesh basket, immersing the mesh basket in the overflow water tank, adjusting the water level, leveling and zeroing the balance, placing a test piece in the mesh basket, immersing for about 3-5 min, and measuring the mass in water after the balance is stable;

the method for calculating the communication porosity comprises the following steps:

in the formula: VV_c-interconnected porosity%;

V_mmm volume of mix and closed voids³；

m_a-the aerial mass g of the dried specimen;

m_w-the underwater mass g of the test piece;

ρ_wdensity of water at-25 deg.C, 0.9971g/cm³；

V-volume mm of the test piece³；

The test results should be expressed as an average of the interconnected porosity of a set of test pieces to the nearest 0.1%.

In step S3, the cement test piece adopts an iron sleeve used by a Marshall compaction method, the test piece is placed for 24 hours after being poured, the test piece is demoulded and is placed in a health preserving room with the temperature of 20 +/-3 ℃ and the humidity of more than or equal to 90 percent for preserving for three days, floating grains on the surface of the test piece are removed when the aerial quality of the test piece is weighed, the Marshall test piece is dried to constant weight by an electric fan, the diameter and the thickness of the test piece are measured by a caliper and are accurate to 0.1mm, the average value of the measurement results of the upper section and the lower section is selected when the diameter is measured, and the average value of four-time cross symmetry measurement is taken as the thickness.

The cement mortar density calculation formula is as follows:

in the formula: rho_sDensity g of the Cement test piece/mm³；

m_s-mass g of cement test piece;

V_svolume mm of the Cement test piece³。

In step S4, before grouting, the bottom and the side of a Marshall test piece are tightly wrapped by a PET plastic plate and transparent adhesive tape, the side is 1-2 cm higher than the test piece so as to facilitate grouting, the mixed cement mortar is slowly poured along one side until the slurry is 1cm higher than the test piece, the slurry does not seep any more, the surface cement mortar is scraped by a scraper, after standing for 24 hours, the test piece is demoulded, placed in a curing chamber with the temperature of 20 +/-3 ℃ and the humidity of more than or equal to 90% for curing for 3 days, the test piece is dried by an electric fan to constant weight, and the aerial quality of the Marshall test piece after grouting is measured.

The perfusion saturation is calculated as:

in the formula: v_c-volume mm of cement mortar poured³；

m'_aThe aerial mass g of the semi-flexible pavement material test piece;

m_athe aerial mass g of the matrix asphalt mixture test piece;

P_r-perfusion saturation;

the test results should be expressed as the average of the perfusion saturations of a set of test pieces to the nearest 0.1%.

One comparative example corresponding to this example is:

step S1: forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

step S2: testing the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

step S3: pouring cement mortar to form a semi-flexible pavement material test piece, wherein the cement mortar is a finished product of cement mortar of a certain brand, the water-cement ratio is 0.42, and the fluidity is 15.3 s;

step S4: and testing the communication porosity of the test piece after curing and demolding, and calculating the perfusion rate of the semi-flexible pavement material test piece.

The method for determining the grouting saturation of the cement mortar of the semi-flexible pavement disclosed by the embodiment has high testing precision, the grouting rate index of the traditional method is obtained by testing the communicated porosity of a test piece after grouting by a twice underwater gravity method and calculating a difference value, a closed volume is possibly formed between cement and an asphalt interface after grouting, the volume of water absorbed by the cement is also taken as the communicated porosity volume, and the testing result is influenced due to inaccurate testing; the method has the advantages that the mass of the test piece before and after grouting and the cement density are weighed to determine the grouting amount and calculate the grouting saturation, the influence of the closed volume between the cement and the asphalt interface and the cement water absorption is avoided, and the obtained result is more accurate;

the operation is more convenient, each test piece needs to be soaked in water for about 3-5 min when the water weight of the test piece after grouting is tested by the traditional method, the number is read after the balance is stabilized, and other tests can be carried out only after the test piece is dried to be constant weight after the test is finished, so that time and labor are wasted; the invention only needs to test the density of the cement mortar once, only needs to test the aerial quality of a test piece using the same proportion of cement mortar, does not need to test the water immersion, and can directly carry out other tests on the test piece after the test is finished.

Example 2

The embodiment discloses a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which comprises the following steps:

step S1: forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

step S2: testing the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

step S3: adopting a certain brand of finished cement mortar, wherein the water-gel ratio is 0.44, the fluidity is 13.5s, forming a cement mortar cylindrical test piece, testing the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece;

step S4: and (3) pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece.

One comparative example corresponding to this example is:

step S1: forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

step S2: testing the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

step S3: pouring cement mortar to form a semi-flexible pavement material test piece, wherein the cement mortar is a finished product of cement mortar of a certain brand, the water-cement ratio is 0.44, and the fluidity is 13.5 s;

step S4: and testing the communication porosity of the test piece after curing and demolding, and calculating the perfusion rate of the semi-flexible pavement material test piece.

Example 3

The embodiment discloses a method for determining the perfusion saturation of cement mortar on a semi-flexible pavement, which comprises the following steps:

step S1: forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

step S2: testing the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

step S3: adopting a certain brand of finished cement mortar, wherein the water-to-gel ratio is 0.46, the fluidity is 11.9s, forming a cement mortar cylindrical test piece, testing the mass and the volume of the test piece after curing and demolding, and calculating the density of the test piece;

step S4: and (3) pouring cement mortar to form a semi-flexible pavement material test piece, testing the quality of the test piece after curing and demolding, and calculating the pouring saturation of the semi-flexible pavement material test piece.

One comparative example corresponding to this example is:

step S1: forming a matrix asphalt mixture test piece, designing the porosity to be 25%, demoulding after 24h, and testing the mass and the volume of the test piece;

step S2: testing the water quality of the test piece, and calculating the communication porosity of the matrix asphalt mixture;

step S3: pouring cement mortar to form a semi-flexible pavement material test piece, wherein the cement mortar is a finished product of cement mortar of a certain brand, the water-cement ratio is 0.46, and the fluidity is 11.9 s;

step S4: and testing the communication porosity of the test piece after curing and demolding, and calculating the perfusion rate of the semi-flexible pavement material test piece.

Referring to fig. 2, the method adopted in this embodiment is compared with the conventional method to compare the test results, and the relation satisfied between the test perfusion saturation of the present invention and the test perfusion rate of the conventional method is obtained as follows:

y＝1.3496x-0.0362

regression coefficient R of this formula²＝0.9737。

The results obtained by the two methods are in a linear relation and have excellent correlation, and the two methods can be considered as different expressions on the same test result; the test pouring saturation of the invention is obviously higher than the test pouring rate of the traditional method, which shows that the method eliminates the influence of the water absorption of the cement material, the test result is closer to the true value, and the method has better guiding function on material design and road construction.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.