The application of Pamikong sponge art pavement in most parts of China has just started, because its construction technology is complex, and many problems are exposed in the process of engineering application, such as quicksand, cracking, poor permeability, etc. Therefore, it is necessary to pay attention to the quality control of the construction process of the permeable concrete sponge art pavement of the Pamikong exposed aggregate to ensure that the permeable concrete sponge art pavement of the Pamikong exposed aggregate achieves the expected effect.
1. The construction process of Pamihole exposed aggregate permeable concrete sponge art pavement.
2. Key points of quality control in the selection of raw materials.
The basic material group of Pamihole Exposed Aggregate Permeable Concrete Sponge Art Pavement includes: clean aggregates, high-grade cement, adhesives, surface protectors, natural colored stones, water, and other materials. To a large extent, it depends on the local bonding of the aggregate and the mud wrapped on the surface of the concrete, the uniform interconnected pores are formed between the aggregate and the concrete to ensure smooth and beautiful, the pores are small and uniform, and the cementation between the aggregate particles is firm, so the single-graded gravel is generally used, the particle size of the surface aggregate is generally 6-9 mm or, the appearance is neat, there are no edges and corners, the needle-like particle content should be less than 1%, and the mud content should be less than 05%, the crushing value should be less than 15%. In order to ensure the porosity (greater than 30%) and compressive strength (C20-C30) of the permeable concrete sponge art pavement of Pami hole exposed aggregate, PO42 is usually used5 or above grade cement for mixing, the compressive strength of cement should be greater than 270mpa, for 3 days, 500MPa for 28 days. In order to improve the flexural strength of the permeable concrete sponge art pavement of Pamihole exposed aggregate, 2% of the Pamihole sponge art pavement reinforcing agent should be added. The test shows that after adding the cement reinforcing agent, the compressive strength of the Pamihole exposed aggregate sponge art pavement can generally be increased by about 20%, and the flexural strength can be increased by more than 30%. The selection of surface protectors should mainly consider wear resistance and anti-aging performance, and acrylic resin materials are generally selected.
3.Key points of Pamihole sponge art pavement mix design.
3.1. Design principles.
Meets strength and permeability (permeability coefficient) requirements.
Meet the requirements of the surface layer for aesthetic wear resistance.
3.2. Pamihole sponge art pavement mix design adjustment.
According to the strength index, a reasonable water-cement ratio, cement content and cement reinforcing agent content were determined.
According to the permeability index, determine the reasonable aggregate particle size, dosage and cement slurry volume.
In order to facilitate grasp and analysis, the volume method is generally used for calculation. The permeability coefficient and compressive strength of Pamihole sponge art pavement are the key indicators that determine its performance, so these two indicators should be considered in the mix design. For C25 and above Pami hole exposed aggregate permeable concrete sponge art pavement, the general water-cement ratio is not greater than 04. The bone cement ratio is 04 or so. With the difference in aggregate particle size ratio and cement properties, corresponding changes will also occur. Before construction, it is necessary to determine a reasonable material ratio through test verification.
4 key points of Pamikong exposed aggregate permeable concrete sponge art pavement construction control.
4.1. Key points of mixing production control.
In order to ensure the uniformity of the pores of the permeable concrete sponge art pavement of the Pami hole exposed aggregate, it is required that the material must be stirred evenly after entering the machine, and there shall be no separation of clay and bone paste in the mixture. Requires the use of a forced mixer for mixing. The capacity of each stirring should be consistent with the construction speed. The time interval from the beginning of mixing to the end of paving should not exceed 30 minutes, so as not to affect the normal bonding and hardening of the slurry. In addition, the feeding amount of each plate of material should be set according to the ratio requirements, and the measurement should be accurate. Not only do you have to visually dosing, but you also have to measure and record each plate. When the aggregate contains water, the mix ratio should be adjusted to ensure that the quantity and consistency of the permeable concrete sponge art pavement slurry of the Pami hole exposed aggregate meet the design requirements.
In order to ensure the permeability coefficient of the permeable concrete sponge art pavement of the Pamihole exposed aggregate, the water addition of the concrete should be strictly controlled during mixing. Too dry will affect the adhesion of the aggregate, too thin will make it difficult for the aggregate to wrap around the slurry, and the slurry deposited at the bottom will clog the pores. Generally, about 50% of the water consumption and aggregate are put into the mixer and stirred for about 60s, and then admixtures, cement and other materials are added, and then stirred for about 30s. After that, add the remaining water to the blender and blend for about 40 minutes. The mixed Pami hole exposed aggregate permeable concrete sponge art pavement should be pinched tightly by hand in groups, loose by hand, and the aggregate should be evenly wrapped in the slurry, not flowing, and the surface of the slurry is bright. When the design requires a colored surface layer, in order to save costs, the construction method of layered construction is generally adopted. First of all, the primary color Pami hole exposed aggregate permeable concrete sponge art pavement is mixed at the bottom layer, and the aggregate can be a slightly larger 10-16mm aggregate to improve the permeability and strength of the concrete. After paving, without pigment, it can be quickly rolled 1-2 times, and then mixed with the surface layer of colored concrete, so as to ensure that the surface layer of color Pami hole exposed aggregate permeable concrete sponge art pavement is paved before the initial setting of the bottom layer. In order to increase the flatness and aesthetics of the permeable concrete sponge art pavement of the surface Pami hole exposed aggregate, the surface layer is generally mixed with 6-9mm small aggregate. At the same time, in order to prevent the bottom layer and surface Pami hole exposed aggregate permeable concrete sponge art pavement mixing and affect the color effect, different mixing equipment is generally used for mixing and transportation.
4.2. Paving construction control points.
Foundation treatment: Before paving the permeable concrete sponge art pavement of Pamihole exposed aggregate, the foundation soil should be tamped first, and then a layer of filter geotextile should be laid, which is used to prevent rainwater from submerging the foundation soil and blocking the pores of the Permehole exposed aggregate permeable concrete sponge art pavement. After the geotextile is laid, a gravel cushion with a thickness of 10-15cm should be laid, and the gravel particle size can be graded gravel with 5-20mm. When the rainstorm season comes, when the base water is too much to penetrate, generally in the middle of the base gravel cushion, a special permeable blind pipe drainage system (about 75mm) is set every about 6 meters, and the low-end drainage system is led to the road to remove excess rainwater in time.
Due to the mixing and drying of the permeable concrete sponge art pavement of the Pamikong exposed aggregate, the water on the surface of the general aggregate slurry evaporates quickly, so the paving construction of the good Pamikong exposed aggregate permeable concrete sponge art pavement should be transported to the job site immediately, according to the construction temperature, the time interval between the mixing of the permeable concrete sponge art pavement of the Pamikong exposed aggregate to the completion of paving compaction should not exceed 30 minutes in summer and 45 minutes in the age season. Since the Pamihole Exposed Aggregate Permeable Concrete Sponge Art Pavement Pavement or Site is usually designed as a colored surface layer, there are two options for the mixing of the Colored Pamihole Exposed Aggregate Permeable Concrete Sponge Art Pavement. One is to directly put 425. White Portland cement is mixed with about 2% color pigment, and the other is to mix ordinary cement with 5%-8% color pigment. It should be noted that more than 3% pigment addition will significantly reduce the strength of the permeable concrete sponge art pavement of Pamihole Exposed Aggregate. It is generally practiced to mix with ordinary cement and add 3%-5% color pigment, and then after the pavement is finished, the surface color is enhanced and supplemented by spraying color paint. In order to improve the aesthetics of the surface layer and extend the life of the color surface layer, it is often necessary to spray a layer of transparent resin on the surface coating surface. Another method is to directly compound the color paint with fluorocarbon protectants to prepare a color resin paint with good weather resistance and wear resistance for spraying, and the effect is just as good.
For the color layer of Pami hole exposed aggregate permeable concrete sponge art pavement, the paving construction is first poured at the bottom of the construction, and the paving coefficient should be 12. Quickly pave and use leveling, and then carry out surface paving after rolling, and ensure that there is a good bond between the surface layer and the bottom aggregate, the lower layer construction should be controlled in an interval of 20 minutes, and the paving construction of the permeable concrete sponge art pavement of Pami hole exposed aggregate should be carried out continuously to avoid fluctuations in the quality of joints. If the paving construction interval reaches more than one hour, it is necessary to set up construction joints and parting molds to ensure that the two paving joints are smooth and of reliable quality.
For the compaction of the permeable concrete sponge art pavement of Pamikong aggregate, a steel roller with a diameter of about 100 mm can be compacted and mechanically leveled. The specific method is to roll the surface layer 2-3 times after scraping, and then use low-frequency vibration rammer to tamp, and the vibration and resistance level at the same position are controlled within 2min. If the compaction time is too long, it will affect the permeation effect, and if the compaction time is too short, it is easy to cause insufficient running and strength. If the mechanical part cannot be tampered with, it should be operated manually to wipe and pat the solid work. The pavement completed by construction should meet the requirements of solid aggregate bonding, uniform pore distribution, fast water permeability, smooth surface compaction, no holes, and no color difference.
4.3. Key points of maintenance construction.
Because the Pamihole exposed aggregate permeable concrete sponge art pavement has many pores, the water volatilizes quickly. In order to ensure the normal setting and hydration of concrete pavement after construction, timely moisturizing and curing is very important. Considering the surface cleanliness of the permeable concrete sponge art pavement of Pamikong exposed aggregate, it is generally not necessary to use straw bales, straw curtains and other materials that should be dispersed and impregnated, and it is better to use plastic film or geotextile for covering and curing. At the same time, water should be sprinkled every day to ensure that the concrete surface is always wet. In general, it can be covered and **20 days or so. During the curing process, a special person should be arranged to take care of it. All vehicular and pedestrian traffic is prohibited, especially to prevent sand and other debris from falling on the surface of the Pamikong exposed aggregate permeable concrete sponge art pavement.
4.4. Key points of expansion joint cutting and grouting construction.
In order to prevent the pavement from cracking due to temperature stress, the construction of cutting expansion joints should be carried out about 3 days after the pavement construction. According to the construction area, an expansion joint should be set every 5 meters. The width of the seam is about 5mm, and the height of the upper layer exceeds 1 2 of the thickness. The cut expansion joints are cleaned with a high-pressure water gun and then stuffed with styrofoam. It can also be filled with colored resin or asphalt material close to the color of the road surface.
4.5. Key points of surface protector spraying construction.
After the construction of the pavement expansion joint of Pamikong exposed aggregate permeable concrete sponge pavement is completed, the surface layer should be cleaned, and the prepared special color protector consistent with the pavement color should be evenly sprayed on the concrete surface within a week. It should be noted that the spraying of surface protector must prevent local enrichment, and cannot block the pores of concrete and affect the permeability effect. After the surface coating is sprayed, it should continue to be supervised by special personnel to ensure that the road surface is clean and free of damage before delivery.
5 Summary: The production and construction technology of Pamikong exposed aggregate permeable concrete sponge art pavement is similar to that of traditional concrete, but the technical requirements are much higher than that of traditional concrete. The use of aggregates and other raw materials that meet the requirements of the permeable concrete sponge art pavement process requirements of Pamikong exposed aggregate, the mix ratio verified by indoor tests, the control of measurement and mixing links, the correct pavement and vibration control, and the later spraying and maintenance are the necessary guarantees for the production of qualified Pamikong exposed aggregate permeable concrete sponge art pavement. Qualified Pami hole exposed aggregate permeable concrete sponge art pavement can not only meet the function of driving and walking, but also has the characteristics of uniform pores, fast permeability, smoothness, firmness, beauty and durability. With the popularization of national sponge city construction, the application of new ecological materials such as Pamikong aggregate permeable concrete sponge art pavement will be more extensive.