Mud-bound macadam takes coarse macadam as main aggregate and clay as joint filler, which has certain strength and stability. Mud-bound macadam surface is suitable for intermediate pavement surface of low-grade highway, with a general thickness of 8~ 12cm.
The specifications of the stone shall conform to the provisions in the following table, the silt content shall not be greater than 15%, the plasticity index shall be 18~27, and the crushing value of the stone shall be less than 35.
Material specification of mud-bound macadam
The number (mm)% passing through the following sieve holes is by weight.
75 50 40 20 10 5
1 100 0~ 15 0~5
Lower level
2 100 0~ 15 0~5
three
100 0~ 15 0~5 surface course
four
85~ 100 0~5
five
85 ~10000 0 ~ 5 joint filling
Grouting method is a common method in construction, and its general process is as follows:
① preparation work; (2) laying gravel; (8) Pre-crushed stone; ④ Grouting; ⑤ Rolling with slurry; ⑧ Final rolling.
1. Preparation, including the preparation of the lower bearing layer and drainage facilities, construction lofting, material pile arrangement and mud mixing. Mud is generally prepared according to the soil-water volume ratio of 0.8 ∶ 1 ~ 1 ∶ 1. Too thick, too thin or uneven will affect the construction quality.
2. Gravel laying and initial rolling should be carried out to stabilize the initial embedding of gravel. Excessive rolling will block gravel cracks and prevent mud from pouring in.
When paving gravel, the loose paving coefficient is 1.20~ 1.30 (1.3 when the ratio of the maximum particle size to the thickness of gravel is about 0.5, and the coefficient is close to 1.2 when the ratio is large). Paving should strive to have a smooth surface and a specified road arch.
Initial compaction: Use an 8-ton double-wheel roller for 3-4 times to stabilize the coarse gravel in place. In a straight section, it is rolled from the shoulders on both sides to the center line of the road; In the ultra-high road section, from the inside out, the wheels are gradually staggered for rolling. Each overlap is 1/3 wheel width. After the first rolling, the rolled elbow should be leveled again. At the end of initial compaction, the surface shall be smooth and have the specified road arch and longitudinal slope.
3. Grouting and rolling with mud. If the gravel is too dry, it can be wetted with water first, so that the mud can be thoroughly poured at one time. After the cement slurry is poured to a considerable area, 5~ 15mm caulking material (about1~1.5m3/100m2) can be laid. Use a medium roller to roll the cement slurry, so that the cement slurry can fully fill the gravel gap. The necessary filling and finishing work will be carried out the next day.
4. Final rolling: When the surface is dry and the internal mud is still in a semi-wet state, the final rolling can be carried out. Generally, after rolling 1 ~ 2 times, spread a thin layer of 3 ~ 5 mm stone chips, and then roll them after sweeping evenly, so that the soil in the cracks in the stone chips will turn to the surface and bond with the scattered stone chips into a whole.
Joints and road joints should be properly handled to ensure smoothness and tightness.
Mud-bound macadam surface: mixing method is adopted for construction.
The construction procedure is: spreading gravel → spreading soil → mixing and forming → rolling. Paving macadam: according to the loose paving thickness, manually spread macadam with grader, and sprinkle water to make macadam completely wet. Soil spreading: spread a specified amount of soil evenly on the gravel surface. Mixing: mechanical mixing or manual mixing. After mixing for one time, sprinkle water and turn it over for 3-4 times, depending on the degree to which the clay slurry and gravel are bonded together. Shaping: Level the road surface with grader to meet the requirements of road arch. Rolling: after molding, use a 6~8t roller to spray water for rolling, so that the mud floats, and stop rolling when there is a layer of mud at the surface joint; After a little drying, use 10~ 12t roller to collect pulp and roll it 1 time, then spread caulking material and roll it for 2~3 times until there are no obvious wheel tracks on the surface.
Mud-bound macadam construction
Mud-bound macadam takes coarse macadam as main aggregate and clay as joint filler, which has certain strength and stability. Mud-bound macadam surface is suitable for intermediate pavement surface of low-grade highway, with a general thickness of 8~ 12cm.
The specifications of the stone shall conform to the provisions in the following table, the silt content shall not be greater than 15%, the plasticity index shall be 18~27, and the crushing value of the stone shall be less than 35.
Material specification of mud-bound macadam
The number (mm)% passing through the following sieve holes is by weight.
75 50 40 20 10 5
11000 ~150 ~ 5 lower layer
2 100 0~ 15 0~5
3 100 0~ 15 0~5 surface course
4 85~ 100 0~5
585 ~10000 0 ~ 5 caulking
Grouting method is a common method in construction, and its general process is as follows:
① preparation work; (2) laying gravel; (8) Pre-crushed stone; ④ Grouting; ⑤ Rolling with slurry; ⑧ Final rolling.
1. Preparation, including the preparation of the lower bearing layer and drainage facilities, construction lofting, material pile arrangement and mud mixing. Mud is generally prepared according to the soil-water volume ratio of 0.8 ∶ 1 ~ 1 ∶ 1. Too thick, too thin or uneven will affect the construction quality.
2. Gravel laying and initial rolling should be carried out to stabilize the initial embedding of gravel. Excessive rolling will block gravel cracks and prevent mud from pouring in.
When paving gravel, the loose paving coefficient is 1.20~ 1.30 (1.3 when the ratio of the maximum particle size to the thickness of gravel is about 0.5, and the coefficient is close to 1.2 when the ratio is large). Paving should strive to have a smooth surface and a specified road arch.
Initial compaction: Use an 8-ton double-wheel roller for 3-4 times to stabilize the coarse gravel in place. In a straight section, it is rolled from the shoulders on both sides to the center line of the road; In the ultra-high road section, from the inside out, the wheels are gradually staggered for rolling. Each overlap is 1/3 wheel width. The rolled elbow shall be leveled again after the first rolling. At the end of initial compaction, the surface shall be smooth and have the specified road arch and longitudinal slope.
3. Grouting and rolling with mud. If the gravel is too dry, it can be wetted with water first, so that the mud can be thoroughly poured at one time. After the cement slurry is poured to a considerable area, 5~ 15mm caulking material (about1~1.5m3/100m2) can be laid.
Use a medium roller to roll the cement slurry, so that the cement slurry can fully fill the gravel gap. The necessary filling and finishing work will be carried out the next day.
4. Final rolling: When the surface is dry and the internal mud is still in a semi-wet state, the final rolling can be carried out. Generally, after rolling 1 ~ 2 times, spread a thin layer of 3 ~ 5 mm stone chips, and then roll them after sweeping evenly, so that the soil in the cracks in the stone chips will turn to the surface and bond with the scattered stone chips into a whole.
Joints and road joints should be properly handled to ensure smoothness and tightness.
(1), construction preparation
Material: tough and wear-resistant crushed granite or limestone, and the crushed stone should be a polygonal block; Mud should be mixed according to the water-soil ratio of 0.8: 1 ~ 1: 1 (volume ratio).
Machines and tools: dump trucks, cars or other transport vehicles are directly unloaded into the road bed as planned, bulldozers or manual paving, sprinklers, road rollers and other tamping machines and tools.
Operating conditions: the subgrade has been fully accepted, the site transportation and mechanical rotation are convenient, and all kinds of test piles are complete and firm, which will not affect the construction of each process.
⑵. Measuring and setting out: Measure and control the pile spacing at 10m. After the control pile layout is completed, drive the φ25 steel pile into one end of the construction section, fix one end of the Zhang Liqi on the steel pile, and fix the wire rope at the other end, and then pull the wire rope to make the Zhang Liqi tension reach more than 10N. The length of steel wire rope in each construction section is 100 ~ 65438. After the wire rope is fixed, put the wire rope into the groove on the top of the test pile and tie it tightly with white wire. If the wire rope droops too much, a support can be added between every two test piles to prevent the wire rope from sinking due to the long distance between piles.
(3), stacking and paving
Division of operation sections: During paving operation, each flow section can be divided into 40 ~ 50m sections, and the number of unloading vehicles can be calculated according to the stone quantity of paving materials. In the construction period, the plum blossom cloth should be placed under the command of a special person. Leveling with bulldozer after unloading. The virtual paving thickness of the gravel layer should be the design thickness multiplied by the loose paving thickness of the compaction coefficient. The compaction coefficient of manual paving is 1.25 ~ 1.30, and that of mechanical paving is 1.20 ~ 1.25. The daily construction length shall be determined according to the mechanical equipment. According to the requirements of construction progress, continuous paving can be carried out in shifts of 8 ~ 10h.
Paving: After the gravel is discharged, it should be leveled in time. Try to use bulldozers for preliminary leveling. If the road width can't meet the working width of bulldozer, it should be leveled manually. According to the setting-out elevation and virtual paving thickness, on-site construction personnel should mark obvious signs with white ash to indicate the leveling elevation for bulldozers, so that bulldozers can level according to the accurate height and cross slope, and create favorable conditions for the next step of voltage stabilization.
Manual cooperation with mechanical construction: during construction, assign special personnel to direct unloading, and the cloth should be even and appropriate. Too much or too little cloth will cause too much workload for bulldozers or manual workers and prolong working hours. Sprinkle water on the surface of the road bed, and the sprinkler should be commanded by a special person. During construction, the surface of the road bed should not be dry, and water and mud on the road surface should not be caused by excessive sprinkling. Sprinkler quantity should be controlled according to the climatic conditions during operation, and the field sprinkler quantity should be adjusted according to the optimal water content. All kinds of mechanical construction must be commanded by a special person from beginning to end, not by many people, and go their own way. Sufficient leveling and trimming personnel shall be provided to repair the corner parts that cannot be machined, and at the same time, the width, elevation, slope and smoothness of the paving layer shall be measured to ensure that the paving surface is qualified.
(4), voltage regulation
It is advisable to use a small roller to slowly stabilize the pressure twice from both sides of the road to the middle of the road, so that the gravel is in its place and closely interspersed to form a plane. After stabilizing the pressure twice, spray water with the water consumption of about 2-2.5kg/m2, and then spray water with the pressure with the water consumption of about 1kg/m2 to keep the stone moist and reduce friction.
5], pouring mud
Immediately after the gravel layer is stabilized, slurry grouting shall be carried out, and the slurry shall be poured evenly to fill the pores between the gravel. The mud surface should be flush with gravel, and the edges and corners of gravel should be exposed above the mud. When grouting, mud must be poured into the bottom of gravel layer. After grouting 1 ~ 2 hours, when the mud sinks and the air in the pores overflows, the stone chip caulking material is scattered on the surface of the wet gravel layer to fill the gap on the surface of the gravel layer.
[6], rolling
After grouting is completed, when the surface of the pavement is dry but the internal mud is still in a semi-wet state, it should be compacted within the full width of the subgrade immediately with a roller.
Rolling from both sides to the center of the road, first pressing the roadside two or three times and then gradually moving to the center. Sprinkling water with pressure is needed from stabilizing pressure to rolling, and the effect is better. Rolling until the surface is smooth, without obvious wheel tracks, and the compaction density is greater than or equal to the design requirements.
If some areas appear "elastic softness" during the rolling process, the rolling should be stopped immediately and rolled after loosening, drying or processing. If it continues, it should be sprayed with proper amount of water, leveled and compacted.
1. Laying a sealing layer
After rolling, the pavement often presents the phenomenon of pits and grooves with bare aggregate and lack of fine materials around, and the pavement in dry areas is prone to looseness. In order to prevent this defect, a cover should be added. The method is to spread a layer of clay slurry on the surface, sweep it evenly with a broom, then spread stone chips, and roll it for 3-4 times with a light roller after sweeping it evenly, and it can be opened to traffic. The thickness of the cover should not be greater than 1cm.