CN1916282A - Gradation method for determining grade of coarse aggregate matched to steady granular material of dense cement - Google Patents

Abstract

The present invention relates to a gradation method of coarse-fine aggregate, said gradation method can be used for providing a graded dense cement-modified aggregate for base course of highway and urban road surface. Said method includes the following steps: calculating the mass percentage of coarse aggregate passing through every sieve opening, calculating the mass percentage of fine aggregate passing through every sieve opening, making the above-mentioned two mass percentages be combined together so as to obtain the aggregate grading curve for preparing graded dense cement-modified aggregate.

Description

The grading method of coarse aggregate gap gradation compact cement stabilized granular and the method for inspection of skeleton thereof

Technical field:

The present invention relates to definite method of the preferred grating of coarse aggregate gap gradation compact cement stabilized macadam and/or gravel and curve thereof and, belong to cement stabilized granular sub-surface field the method for inspection of cement stabilized granular framework dense structure.

Background technology:

As far back as nineteen thirty-seven California, USA success making 3.2km cement stabilized soil highway road surface.Some countries research successively subsequently and use cement stabilized granulars comprises that rock rubble, slag rubble, crushing gravel, gravel etc. do the basic unit of highway and urban road surfaces.In the world, the title cement punishment basic unit (CTB) that has, the title cement that has knot pellet (CBG).China often is called for short cement stabilized soil, and when being used as basic unit, cement stabilizing grating commonly used is gathered materials and is called for short cement stabilized macadam or cement gravel.Before early 1980s, Britain is divided into poor concrete by the big young pathbreaker's cement of compressive strength knot material sections, and its, compressive strength reached 15MPa, cement knot granular base course and cement stabilized soil in seven day length of time.Britain in 1986 ties material with cement and unifies called after CBM1, CBM2, CBM3 and CBM4.In fact CBM4 is equivalent to former poor concrete, the unconfined compression strength R in the seven day length of time ₇, the R of 5 test specimens ₇=15MPa, single value＞10MPa.The R of CBM3 ₇, the R of 5 test specimens ₇=10MPa, single value＞6.5MPa.The R of CBM2 ₇, the R of 5 test specimens ₇=7MPa, single value＞4.5MPa.The R of CBM1 ₇, the R of 5 test specimens ₇=4.5MPa, single value＞2.5MPa.

Only CBM1 and CBM2 allow with plantmix or road mix, and CBM3 and CBM4 must use plantmix.CBM1 is as subbase.

When Spain's cement knot pellet is used as basic unit, require R ₇=6.0MPa.

In the sixties in 20th century, the area that uses the cement stabilizing material to do (containing stable granulate, pellet soil and soil) sub-surface and subbase in the North America is equivalent to 80,000 km two-lane highwaies approximately.At the beginning of the seventies in last century, China begins one's study in the highway engineering of helping build of states such as Zambia and a large amount of basic unit that uses cement stabilized granular soil to do asphalt surface course.Domestic Liaoning Province has held up on the highway first making in Shen in 1974 the long cement Stability Gravel of about km more than 10 basic unit.Guangxi autonomous region in 1977 on highway making long cement Stability Gravel of km more than 20 and cement stabilizing dust soil matrix layer.Since the beginning of the eighties, cement stabilized granular (rubble and gravel) basic unit generally is used for the basic unit of high-grade highway and ordinary highway flexible pavement and cement concrete pavement.

In the use of cement stabilized granular base course, the country that has has produced some quality problems, and has reduced application, or is used as subbase below putting it to, and the country that has then uses quite successfully.Most speedways use successfully in China, and the speedway that has only part bid section uses successfully, and the speedway that has has produced serious quality problems.

The reason that causes the cement stabilized granular base course poor quality is many-sided:

(1) grating or particle compositing range are wide

The aggregate grading scope that some countries adopt sees table 1,

Table 1: with the particle compositing range that gathers materials of cement stabilizing

The source	Quality percentage (%) by following sieve aperture (mm)
													75	40			20		5	2 or 2.5	1	0.42 or 0.50	0.15	0.075
	France	100	90～100 100			45～85 75～100		25～45 30～50		5～35 10～40		0～10 0～10
The U.S.													100						＞50			＞15		＜50
	Canada	100						＞50			＞15														＜50
Japan														95～100 95～100			50～100 50～100	40～100		20～60 20～70				0～15 0～20
	Britain CBM1 CBM2 CBM3 CBM4	(50mm) 100 100 100		(37.5) 95 95～100 95～100 100		45 45～100 45～80 95～100	(10) 35 35～100	25 25～100 25～50 35～55	(2.36) 15～90		(0.6) 8 8～65 8～30 10～35	(0.3) 5 5～40 0～8 0～8													0 0～10
The Europe North-South Freeway																	85～100	55～80	37～61	23～43		11～26	7～17	4～10

Seen that by table 1 external used grading limit is very wide, the scope of same screen size throughput is everlasting between 20%～50%.

Though the grading limit in the highway in China constructing road foundation technical specification is more a lot of than having dwindled in the table 1, also is wide, sees table 2.

Table 2: the cement pellet particle compositing range table of domestic constructing road foundation standard

Screen size (mm)	31.5	26.5	19	9.5	4.75	2.36	0.6	0.075
									By quality (%)	100	90～100	72～89	47～67	29～49	17～35	8～22	0～7

The maximum magnitude of same sieve aperture throughput is 20% in the table 2.

Scope is wide to provide sizable degree of freedom to unit in charge of construction.Think as long as the particle composition can in this scope.In fact, the pellet level prepares inferior intensity to cement stabilized granular appreciable impact.

(2) do not have the aggregate grading method for designing, do not have the whether suitable method of inspection of aggregate grading yet.Allot that the cement pellet compound that comes is whether suitable then feels unsure of.After can only waiting for that mechanical property test is finished, can know just whether aggregate grading is only.Lack necessary theory testing method, can only just can find optimum aggregate grading and most economical cement consumption by comparative test repeatedly.This need spend long time and input.

(3) raw material (only referring to pellet) are not had clear and definite specification, particularly do not have the particle composition requirement.China only requires raw material are divided into 3～4 grades that vary in size, and is made into grating with gathering materials of these 3～4 size fractionated and gathers materials.After pressing the definite cement consumption of strength criterion test, just begin to produce.The match ratio of determining may be used all no longer changes of engineering end always for the first time.But owing to multiple reason, it is impossible to change in this process that the raw-material particle of purchasing is formed.Thereby cause the intensity of the cement pellet of being produced to produce sizable variation.At the construction field (site), the big I of often finding the compressive strength of the brill spare that diverse location is got differs 3～4 times.And often find that basic unit can not get complete brill spare.The brill spare top layer 1～2cm that has is loose, fracture in the middle of the brill spare that has, and the brill spare bottom that has is loose, and the brill spare that can not have normal cylinder, but the olive karyomorphism.

Summary of the invention

Main purpose of the present invention is that the cement stabilized granular base course for highway and urban road surfaces provides a kind of grading method that more helps the coarse aggregate gap gradation compact cement stabilized granular closely knit, that intensity is high, sensitiveness is little.

Another object of the present invention is that the compact structure of test specimen skeleton that the cement stabilized granular that utilizes the said method grating is made provides a kind of and saves time, the laborsaving and economical method of inspection.

The grading method of coarse aggregate gap gradation compact cement stabilized granular of the present invention comprises the steps:

1. the grading method that coarse aggregate gap gradation compact cement stabilized granular base course gathers materials is characterized in that comprising the following steps:

(1) will gather materials and be divided into coarse aggregate, fine aggregate and powder (filler) three parts;

(2) the nominal maximum particle diameter by cement stabilized granular is that 19mm and 26.5mm screening coarse aggregate are stand-by;

(3) screening fine aggregate: it is that the fine aggregate of 4.75mm～2.36mm, 2.36mm～1.18mm, 1.18mm～0.6mm, 0.6mm～0.3mm, 0.3mm～0.15mm, six grades of 0.15mm～0.075mm is stand-by that the fine aggregate building stones are sieved into particle diameter;

(4) primary election match ratio: with mass percent primary election coarse aggregate rubble 58%～70%, fine aggregate building stones 25%～40%, powder 3%～10%, three kinds of aggregate content sums equal 100%;

(5) calculate the quality percentage that pass through of each sieve aperture pellet of coarse aggregate, the following general formula of foundation:

$P_{\mathrm{di}}=A{\left(\frac{d_i}{D_{\max }}\right)}^B$

In the formula: P _Di---the throughput (%) of certain screen size di;

D _Max---the actual maximum particle diameter of mineral aggregate, the i.e. screen size of a sieve (mm) above the nominal maximum particle diameter;

d _i---certain screen size (mm);

A, B---undetermined coefficient;

With coarse aggregate nominal maximum particle diameter D _Max.nThroughput be 90%～100% some percentage as first control point, be that 30%～42% some percentage is as second control point with coarse aggregate minimum grain size throughput; Use D _Max.nAs the d in the above-mentioned general formula _i, first control point is as the P in the general formula _Di, set up first equation according to above-mentioned general formula; With the coarse aggregate minimum grain size as the d in the general formula _i, with coarse aggregate minimum grain size throughput, promptly second control point is as P in the general formula _Di, set up second equation according to above-mentioned general formula; Above-mentioned first equation and second equations simultaneousness are separated this simultaneous equations, can determine the coefficient A in the general formula, the value of B, with A, the above-mentioned general formula of B substitution and obtain the power function equation of a definite coarse aggregate grating; The pellet that calculates from coarse aggregate nominal maximum particle diameter to each sieve aperture of coarse aggregate minimum grain size with this power function passes through quality percentage then;

(6) calculate the quality percentage that passes through of each sieve aperture building stones of fine aggregate: with the fine aggregate maximum particle diameter as the D in the general formula _MaxAnd d _i, fine aggregate maximum particle diameter throughput is that 30%～42% the percentage identical with second control point is as the P in the formula _Di, set up first equation according to the general formula in the substep (5); With the fine aggregate minimum grain size as the d in the formula _i, the some percentage between its throughput 3%～10%, i.e. the 3rd control point is as the P in the formula _Di, set up second equation according to the general formula in the substep (5), can determine the coefficient A in the above-mentioned general formula, the value of B; A, the above-mentioned general formula of B substitution are promptly obtained the power function equation of a definite fine aggregate grating; Calculate the quality percentage that passes through then from the fine aggregate maximum particle diameter to each sieve aperture fine aggregate of fine aggregate minimum grain size;

(7) coarse aggregate that above-mentioned (5) and (6) substep is calculated and the quality percentage that passes through of each sieve aperture building stones of fine aggregate are combined, and just draw the aggregate grading curve of coarse aggregate gap gradation compact cement stabilized granular; The difference of adjacent two sieve aperture throughputs is certain grade stone shared quality percentage in whole mineral aggregates; 0.075mm the throughput of sieve aperture is powder;

(8), according to the porosity of coarse aggregate in the cement stabilized granular test specimen than fine aggregate, powder and the effectively requirement of the volume sum big 3% of water, check is also adjusted fine aggregate and/or powder in the aggregate grading; According to adjusted new match ratio, recomputate and the new corresponding aggregate grading curve of match ratio with above-mentioned general formula.

Three kinds of particle size range of gathering materials described in above-mentioned (1) step are respectively: the particle diameter of powder is less than 0.075mm, and fine aggregate is 0.075mm～4.75mm, and coarse aggregate is 4.75mm～actual maximum particle diameter.

The particle diameter of above-mentioned coarse aggregate further is subdivided into: for CBG-25, being divided into grade is that 26.5mm～19mm, 19mm～16mm, 16mm～13.2mm, 13.2mm～9.5mm, five grades of 9.5mm～4.75mm or 26.5mm～19mm, 19mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by; For CBG-20, being divided into grade is that 19mm～16mm, 16mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by.

It mainly is according to the satisfactory cement dosage of cement stabilized granular unconfined compression strength in the seven day length of time that the framework dense structure of the test specimen that the cement stabilized granular that utilizes the said method grating is made provides a kind of method of inspection, determines the optimum moisture content and the maximum dry density of cement stabilized granular with the modified compaction test method; The air factor of check test specimen under optimum moisture content and actual dry density situation; This air factor can be made as 3%.Specifically comprise the steps:

(1) makes the compaction test of three kinds of compounds of different cement dosage of the modified compaction test method, determine the optimum moisture content W of different cement dosage compounds _oWith maximum dry density γ _D.max

(2) by unconfined compression strength standard R in the 7 day length of time ₇=3～6MPa, suitable cement dosage is determined in test, make high for CBG-25: diameter is the cylinder test specimen of 15cm: 15cm, make high for CBG-20: diameter is the cylinder test specimen of 10cm: 10cm, the density of test specimen is the maximum dry density of 100%～102% modified compaction test method, and water content is the optimum moisture content of modified compaction test method; Test specimen quantity CBG-20 is 9, and CBG-25 is 13; Test specimen wet curing six days under set point of temperature soaks and does unconfined compression strength test after one day; Calculate the average R of result of the test ₇With coefficient of variation C _vRegulation by " highway road surface construction technique normalizing " is judged the R that needs employing with following formula ₇With cement dosage:

${\stackrel{\‾}{R}}_7\≥\frac{R_d}{(1-Z_{\mathrm{\α}}{C}_v)}$

In the formula: Z _α--the value the in-gaussian distribution table, get 1.645

(3) according to the porosity of coarse aggregate and the volume sum of fine aggregate, powder, cement and effective water, this and can be called cement mortar, fine aggregate and/or powder in the above-mentioned aggregate grading are checked and adjusted to the porosity (being no more than 3%) that requirement that equates or cement mortar are slightly less than coarse aggregate; According to adjusted new match ratio, redefine and the new corresponding aggregate grading curve of match ratio with said method.

The method of inspection is characterized in that comprising the steps:

(1) determines the initial data of each grade stone of coarse aggregate gap gradation compact cement stabilized granular, grading method according to coarse aggregate gap gradation compact cement stabilized granular is listed the aggregate grading curve, and calculates the percent content from the coarse aggregate maximum particle diameter to each grade stone of powder; List the bulk density G that tests each grade stone that obtains _bApparent density G with powder _A.poAnd the apparent density G of cement _A.c(g/cm ³); Calculate and list the percent content P of coarse aggregate in the coarse aggregate gap gradation compact cement stabilized granular _Ca(%); The percent content P of fine aggregate _Fa(%), the percent content Ppo (%) of powder, the optimum moisture content W of dosage Pc (%) test specimen of cement ₀With maximum dry density γ _D.max

(2) test specimen of decomposition analysis actual density, it specifically comprises following substep:

1) determine the initial data of coarse aggregate gap gradation compact cement stabilized granular:

In above-mentioned (1), the listed data, also need to calculate the bulk density G of coarse aggregate _B.ca, fine aggregate bulk density G _B.fa:

2) calculate master data:

The mass M We of the mass M C of the mass M FA of the mass M MA that all gathers materials in the actual dry density calculation testing piece with cement stabilized granular, the mass M CA of coarse aggregate, fine aggregate, the mass M PO of powder, cement, effective water;

The mass M MA=γ that all gathers materials _dThe mass M CA=P of ÷ (1+Pc), coarse aggregate _CaThe mass M FA=P of * MMA, fine aggregate _FaThe quality We. of the mass M C=Pc of the mass M PO=Ppo of * MMA, powder * MMA, cement * MMA and effective water

3) calculate the judgement data

The volume We of effective water

Result of calculation should meet the following formula requirement:

$\mathrm{VCA}=\frac{\mathrm{MFA}}{G_{b.\mathrm{fa}}}+\frac{\mathrm{MPO}}{\mathrm{Ga}.\mathrm{po}}+\frac{\mathrm{MC}}{\mathrm{Ga}.c}+\mathrm{We}+3\%$

More than every calculating all in decimal,

4) judge: if the value on equal sign right side equals the value in equal sign left side in the following formula, then the aggregate grading of cement stabilized granular belongs to coarse aggregate gap gradation compact structure; If the value on equal sign right side less than the value in equal sign left side, should increase the content of fine aggregate and/or powder; Otherwise, if the value on equal sign right side greater than the value in equal sign left side, should reduce the content of fine aggregate and/or powder.

Advantage of the present invention:

1. utilize aggregate grading method of the present invention, can calculate the graduation curve of coarse aggregate gap gradation compact cement stabilized granular easily, avoided the complete in the past way of determining aggregate grading by rule of thumb.

2. utilize the coarse aggregate framework dense structure method of inspection of the present invention, both can make the cement stabilized granular of used grating become framework dense structure, satisfy the requirement of functional performance, can avoid the process of feeling one's way into again by a large amount of tests, reach save time, laborsaving, economize on the use of funds.

3. the aggregate grading method of inspection provided by the invention can make the user check new aggregate grading whether to meet framework dense structure easily.

The specific embodiment

Coarse aggregate gap gradation compact cement stabilized granular grading method of the present invention specifically comprises the following steps:

(1) determine the graduation curve of coarse aggregate gap gradation cement stabilized granular:

(1) will gather materials and be divided into three parts, promptly actual maximum particle diameter～4.75mm is a coarse aggregate, and 4.75mm～0.075mm is a fine aggregate, and＜0.075mm is a powder;

(2) by nominal maximum particle diameter screening coarse aggregate: for CBG-25, being divided into grade is that 26.5mm～19mm, 19mm～16mm, 16mm～13.2mm, 13.2mm～9.5mm, five grades of 9.5mm～4.75mm or 26.5mm～19mm, 19mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by; For CBG-20, being divided into grade is that 19mm～16mm, 16mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by;

(3) screening fine aggregate: it is that the fine aggregate of 4.75mm～2.36mm, 2.36mm～1.18mm, 1.18mm～0.6mm, 0.6mm～0.3mm, 0.3mm～0.15mm, six grades of 0.15mm～0.075mm is stand-by that fine aggregate is sieved into particle diameter;

(4) choose charge ratio: choose coarse aggregate rubble 58%～70% with mass percent, choose fine aggregate building stones 25%～40%, choose filler 3%～10%, three kinds of aggregate content sums equal 100%;

(5) calculate the quality percentage that pass through of each sieve aperture rubble of coarse aggregate, the following general formula of foundation:

$P_{\mathrm{di}}=A{\left(\frac{d_i}{D_{\max }}\right)}^B$

In the formula: P _Di---certain screen size d _iThroughput (%)

D _Max---the actual maximum particle diameter (mm) of mineral aggregate

d _i---certain screen size (mm)

A, B---coefficient

With coarse aggregate nominal maximum particle diameter D _Max.nThroughput be 90%～100% some percentage as first control point, be that 30%～42% some percentage is as second control point with coarse aggregate minimum grain size throughput; Use D _Max.nAs the d in the above-mentioned general formula _i, first control point is as the P in the general formula _Di, set up first equation according to above-mentioned general formula; With the coarse aggregate minimum grain size as the d in the general formula _i, with coarse aggregate minimum grain size throughput, promptly second control point is as P in the general formula _Di, set up second equation according to above-mentioned general formula; Above-mentioned first equation and second equations simultaneousness are separated this simultaneous equations, can determine the coefficient A in the general formula, the value of B, A, the above-mentioned general formula of B substitution are obtained the power function equation of a definite coarse aggregate grating; The rubble that calculates from coarse aggregate nominal maximum particle diameter to each sieve aperture of coarse aggregate minimum grain size with this power function equation passes through quality percentage;

(6) calculate the quality percentage that passes through of each sieve aperture building stones of fine aggregate.According to the general formula in (5) step by step, with the fine aggregate maximum particle diameter as the D in the general formula _MaxWith the d in first equation _i, the number identical with calculating second control point that the coarse aggregate grating adopts of 30%～42% of the throughput of fine aggregate maximum particle diameter be as the control point, i.e. P in the general formula _DiSet up first equation; With the fine aggregate minimum grain size as the d in the general formula _i, a certain number between the fine aggregate minimum grain size throughput 3%～10% is as the 3rd control point, i.e. P in the general formula _DiSet up second equation.First equation and second equations simultaneousness are separated this simultaneous equations, determine the coefficient A in the above-mentioned general formula, the value of B, obtain the power function equation of each sieve aperture of calculating fine aggregate by quality percentage.With the pass through quality percentage of this power function equation calculating from the fine aggregate maximum particle diameter to each sieve aperture fine aggregate of fine aggregate minimum grain size;

(7) quality percentage that passes through of coarse aggregate, each sieve aperture building stones of fine aggregate and the powder that above-mentioned substep (5) and (6) are calculated is bonded together, and just obtains the graduation curve of coarse aggregate gap gradation cement stabilized granular; The difference of adjacent two sieve aperture throughputs is certain grade stone shared quality percentage in whole mineral aggregates; 0.075mm the throughput of sieve aperture is powder.

(8), according to the porosity of coarse aggregate in the cement stabilized granular test specimen than fine aggregate, powder and the effectively requirement of the volume sum big 3% of water, check is also adjusted fine aggregate and/or powder in the aggregate grading; According to adjusted new match ratio, recomputate and the new corresponding aggregate grading curve of match ratio with above-mentioned general formula.

(2) check of coarse aggregate gap gradation framework dense structure cement stabilized granular grating.

The method of inspection of coarse aggregate gap gradation framework dense structure cement stabilized granular grating of the present invention claims VCA _CGMethod.It is to form the satisfactory cement dosage of the intensity test specimen that design obtains and test doing compound, determines whether it is framework dense structure.Check specifically comprises the following steps:

(1) determines the initial data that each grade of coarse aggregate gap gradation compact cement stabilized granular is gathered materials: list the aggregate grading curve that step () obtains, and calculate percent content from the coarse aggregate maximum particle diameter to each grade stone of powder; Density test by building stones obtains the bulk density G from the coarse aggregate maximum particle diameter to each grade stone of fine aggregate minimum grain size _B.aApparent density G with powder _A.PO(g/cm ³), test the density G that obtains cement by cement density _c(g/cm ³); Calculate and list the percent content P of coarse aggregate in the coarse aggregate gap gradation cement stabilized granular _Ca(%); The percent content P of fine aggregate _Fa(%), the percent content P of powder _Po(%), calculate and list the bulk density G of coarse aggregate _B.ca(g/cm ³) and the bulk density G of fine aggregate _B.fa(g/cm ³);

(2) do modified compaction test with the compound of different cement dosage, determine the optimum moisture content and the maximum dry density of cement admixture;

(3) make the cylinder test specimen of different cement dosage compounds, the water content of test specimen is an optimum moisture content, and the dry density of test specimen is 100%～102% maximum dry density, does unconfined compression strength test after the health, determines the satisfactory cement dosage of intensity;

(4) to the satisfactory cement stabilized granular test specimen of intensity, carry out decomposition analysis with its actual dry density and optimum moisture content; Porosity according to coarse aggregate in the cement stabilized granular test specimen is slightly larger than fine aggregate, powder, cement and effective water (W _e) the requirement (being no more than 3%) of volume sum, that is:

VCA＝VOLFA+VOLPO+VOLC+VOLWe

Calculate the porosity (equal sign left side in the formula) of coarse aggregate respectively, the volume sum (equal sign right side) of fine aggregate, powder, cement and effective water; The quality W of effective water _eShould be optimum moisture content W _oThe water W that-cement aquation needs _b

(5) if the value in equal sign left side is no more than 3% greater than the value on equal sign right side in the following formula, the volume that explanation is made up of fine aggregate, powder, cement and effective water can not fill up the hole of coarse aggregate, the framework dense structure that this coarse aggregate gap gradation cement stabilized granular grating forms also has 3% air factor, and the cement stabilized granular of Gou Chenging meets the requirements thus; Otherwise, if the value in equal sign left side illustrates that less than the value on equal sign right side the hole of coarse aggregate can not hold the mastic cement of being made up of fine aggregate, powder and Free water.Surpass 1% as little value, then the framework dense structure of Xing Chenging will be strutted by mastic cement, even coarse aggregate is suspended in the mastic cement.The intensity of the cement stabilized granular of Gou Chenging can affect adversely thus, and the surface roughness of basic unit can diminish, thereby influences interlaminar bonding.Should reduce the content of fine aggregate or powder; According to adjusted new match ratio, recomputate and the new corresponding gradation curve of mineral aggregate of match ratio with above-mentioned general formula.The formulation of the cement blend of reforming then designs, and determines to meet the cement dosage of requirement of strength.

Claims (5)

1. the grading method that coarse aggregate gap gradation compact cement stabilized granular base course gathers materials is characterized in that comprising the following steps:

(1) will gather materials and be divided into coarse aggregate, fine aggregate and powder three parts;

(2) the nominal maximum particle diameter by cement stabilized granular is that 19mm and 26.5mm screening coarse aggregate are stand-by;

(3) screening fine aggregate: it is that the fine aggregate of 4.75mm～2.36mm, 2.36mm～1.18mm, 1.18mm～0.6mm, 0.6mm～0.3mm, 0.3mm～0.15mm, six grades of 0.15mm～0.075mm is stand-by that the fine aggregate building stones are sieved into particle diameter;

(4) primary election match ratio: with mass percent primary election coarse aggregate rubble 58%～70%, fine aggregate building stones 25%～40%, powder 3%～10%, three kinds of aggregate content sums equal 100%;

(5) calculate the quality percentage that pass through of each sieve aperture pellet of coarse aggregate, the following general formula of foundation:

$P_{\mathrm{di}}=A{\left(\frac{d_i}{D_{\max }}\right)}^B$

In the formula: P _Di---the throughput (%) of certain screen size di;

D _Max---the actual maximum particle diameter of mineral aggregate, the i.e. screen size of a sieve (mm) above the nominal maximum particle diameter;

d _i---certain screen size (mm);

A, B---undetermined coefficient;

With coarse aggregate nominal maximum particle diameter D _Max.nThroughput be 90%～100% some percentage as first control point, be that 30%～42% some percentage is as second control point with coarse aggregate minimum grain size throughput; Use D _Max.nAs the d in the above-mentioned general formula _i, first control point is as the P in the general formula _Di, set up first equation according to above-mentioned general formula; With the coarse aggregate minimum grain size as the d in the general formula _i, with coarse aggregate minimum grain size throughput, promptly second control point is as P in the general formula _Di, set up second equation according to above-mentioned general formula; Above-mentioned first equation and second equations simultaneousness are separated this simultaneous equations, can determine the coefficient A in the general formula, the value of B, with A, the above-mentioned general formula of B substitution and obtain the power function equation of a definite coarse aggregate grating; The pellet that calculates from coarse aggregate nominal maximum particle diameter to each sieve aperture of coarse aggregate minimum grain size with this power function passes through quality percentage then;

(6) calculate the quality percentage that passes through of each sieve aperture building stones of fine aggregate: with the fine aggregate maximum particle diameter as the D in the general formula _MaxAnd d _i, fine aggregate maximum particle diameter throughput is that 30%～42% the percentage identical with second control point is as the P in the formula _Di, set up first equation according to the general formula in the substep (5); With the fine aggregate minimum grain size as the d in the formula _i, the some percentage between its throughput 3%～10%, i.e. the 3rd control point is as the P in the formula _Di, set up second equation according to the general formula in the substep (5), can determine the coefficient A in the above-mentioned general formula, the value of B; A, the above-mentioned general formula of B substitution are promptly obtained the power function equation of a definite fine aggregate grating; Calculate the quality percentage that passes through then from the fine aggregate maximum particle diameter to each sieve aperture fine aggregate of fine aggregate minimum grain size;

(7) coarse aggregate that above-mentioned (5) and (6) substep is calculated and the quality percentage that passes through of each sieve aperture building stones of fine aggregate are combined, and just draw the aggregate grading curve of coarse aggregate gap gradation compact cement stabilized granular; The difference of adjacent two sieve aperture throughputs is certain grade stone shared quality percentage in whole mineral aggregates; 0.075mm the throughput of sieve aperture is powder;

(8), according to the porosity of coarse aggregate in the cement stabilized granular test specimen than fine aggregate, powder and the effectively requirement of the volume sum big 3% of water, check is also adjusted fine aggregate and/or powder in the aggregate grading; According to adjusted new match ratio, recomputate and the new corresponding aggregate grading curve of match ratio with above-mentioned general formula.

2, the grading method of coarse aggregate gap gradation compact cement stabilized granular as claimed in claim 1, it is characterized in that three kinds of particle size range of gathering materials described in the 1st step are respectively: the particle diameter of powder is less than 0.075mm, fine aggregate is 0.075mm～4.75mm, and coarse aggregate is 4.75mm～actual maximum particle diameter.

3. the grading method of coarse aggregate gap gradation compact cement stabilized granular according to claim 2, the further screening of particle diameter that it is characterized in that described coarse aggregate is: for CBG-25, being divided into grade is that 26.5mm～19mm, 19mm～16mm, 16mm～13.2mm, 13.2mm～9.5mm, five grades of 9.5mm～4.75mm or 26.5mm～19mm, 19mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by; For CBG-20, being divided into grade is that 19mm～16mm, 16mm～13.2mm, four grades of 13.2mm～9.5mm, 9.5mm～4.75mm are stand-by.

4, the method for inspection of the coarse aggregate gap gradation compact cement stabilized granular aggregate grading of right 1, it is characterized in that determining the optimum moisture content and the maximum dry density of cement stabilized granular with the modified compaction test method according to the satisfactory cement dosage of cement stabilized granular unconfined compression strength in the seven day length of time; The air factor of check test specimen under optimum moisture content and actual dry density situation; This air factor can be made as 3%.

5. according to the method for inspection of the described coarse aggregate gap gradation compact of claim 4 cement stabilized granular aggregate grading, it is characterized in that comprising the steps:

(1) determines the initial data of each grade stone of coarse aggregate gap gradation compact cement stabilized granular, grading method according to coarse aggregate gap gradation compact cement stabilized granular is listed the aggregate grading curve, and calculates the percent content from the coarse aggregate maximum particle diameter to each grade stone of powder; List the bulk density G that tests each grade stone that obtains _bWith surface drying density G _SdApparent density G with powder _A.poAnd the apparent density G of cement _A.c(g/cm ³); Calculate and list the percent content P of coarse aggregate in the coarse aggregate gap gradation compact cement stabilized granular _Ca(%); The percent content P of fine aggregate _Fa(%), the percent content Ppo (%) of powder, the optimum moisture content W of dosage Pc (%) test specimen of cement ₀With maximum dry density γ _Dmax

(2) test specimen of decomposition analysis actual density, it specifically comprises following substep:

1) determine the initial data of coarse aggregate gap gradation compact cement stabilized granular:

In above-mentioned (1), the listed data, also need to calculate the bulk density G of coarse aggregate _B.ca, fine aggregate bulk density G _B.fa

2) calculate master data:

The mass M we of the mass M C of the mass M FA of the mass M MA that all gathers materials in the actual dry density calculation testing piece with cement stabilized granular, the mass M CA of coarse aggregate, fine aggregate, the mass M Po of powder, cement, effective water;

The mass M MA=γ that all gathers materials _dThe mass M CA=P of ÷ (1+Pc), coarse aggregate _CaThe mass M FA=P of * MMA, fine aggregate _FaThe quality We. of the mass M C=Pc of the mass M PO=Ppo of * MMA, powder * MMA, cement * MMA and effective water

3) calculate the judgement data

The porosity of coarse aggregate $\mathrm{VCA}=1-\frac{\mathrm{MGA}}{G_{b\·\mathrm{ca}}}$

The volume of fine aggregate

The volume of powder

The volume of cement The volume W of effective water _eResult of calculation should meet the following formula requirement:

$\mathrm{VCA}=\frac{\mathrm{MFA}}{G_{b\·\mathrm{fa}}}+\frac{\mathrm{MPO}}{\mathrm{Ga}.\mathrm{po}}+\frac{\mathrm{MC}}{\mathrm{Ga}.c}+\mathrm{We}+3\%$

More than every calculating all in decimal.

4) judge: if the value on equal sign right side equals the value in equal sign left side in the following formula, then the aggregate grading of cement stabilized granular belongs to coarse aggregate gap gradation compact structure; If the value on equal sign right side less than the value in equal sign left side, should increase the content of fine aggregate and/or powder; Otherwise, if the value on equal sign right side greater than the value in equal sign left side, should reduce the content of fine aggregate and/or powder.