The advent of the global information age and the acceleration of China's economic development have provided unprecedented opportunities for the development of higher education, which has also led to a wave of college and university construction. The rapid expansion of university school planning will inevitably have a great impact on the surrounding ecological environment, and the current general school roads have severe cracking and damage. In addition, the large-scale general concrete pavement greatly reduces the infiltration of rainwater and the return of groundwater, which severely constitutes the lack of groundwater in the area, and then causes the foundation to sink and damage the school concrete pavement.
Taking the East Campus of Yangtze University as an example, the foundation pavement of the school is completely made of general concrete. It took more than ten years or even decades, and the pavement was significantly damaged. The lack of a 100m pavement from the school's east gate to the wind and rain stadium has hundreds of cracks. The main reasons are the excessive damage caused by vehicle traffic loads, the unreasonable expansion joints between concrete plates, the subsidence of the pavement foundation, and the freeze-thaw cycle. Thermal stresses occur in cracks. In addition, the school is located in the Jianghan Plain. The geological structure is dominated by soft soil. Under the load effect, the ground plate is vacated to cause large tensile stress on the ground plate, which causes damage. Due to the difference in strength, different degrees of settlement occur at the joints between the paved concrete plates. The deepest surpasses 10 cm and the length exceeds 40 cm. The large-scale surface plaster drop phenomenon appears, which severely affects the school's traffic and appearance. It can be seen that it is necessary to find a new kind of information or more advanced construction skills to deal with the above-mentioned problems-the use of ecological permeable bricks
for school pavement construction.
The materials used in ecological permeable bricks
are made of various waste ceramics, quartz sand, and square bricks. The bottom materials are ceramic waste. The materials have been collected from other manufacturers at low prices. In this way, the waste products of the factory products are digested in situ and converted into qualified products of another product, forming a closed product production chain. The ecological concept of turning waste into treasure is adopted to dispose of university construction waste in situ, which reduces costs and improves economic efficiency. Most universities today have a problem of lack of funds. Saving construction costs and reducing construction costs are practical issues that all universities must consider.
Ecological permeable bricks
have very strong water permeability and water retention. The water permeability can reach more than 8mm / s, and its water retention can reach more than 12L / m2. Because of its outstanding water permeability and water retention, rainwater will automatically penetrate the bottom of the brick to the ground when it rains, and a part of the water is preserved
Inside the brick. Rainwater does not flow around like it does on a concrete pavement, and eventually flows completely into the river through a sewer. When the weather is fine, the water that enters under the bricks or stored in the bricks will evaporate into the atmosphere, which will regulate the humidity of the air, reduce the atmospheric temperature, and eliminate the "heat island" of the city.
Effect. In most areas of our country, there is a large amount of rainwater surface runoff due to heavy rainfall. From time to time, the phenomenon of rain engulfing roads and cities is seen. Ecological permeable bricks
not only alleviate the pressure of rainwater gathering to a certain extent, but also supply most of the rainwater to the groundwater through the permeable bricks
. Its water retention function can better alleviate the dryness and heat of the air when the weather is fine.
The excellent water permeability and water retention have originated from the porosity of about 20% of this product. With such a large porosity, most people will wonder if its strength is as small as that of lightweight refractory bricks. In fact, the strength of this product can reach more than 120kgf / cm2. When it is laid in a parking lot, it can overload cars with a load of 40T or more. Overseas, such as Japan, urban sidewalks, pedestrian streets, apartment parking lots, airports and other places are basically replaced with cement and stone hardened pavement. Why does this product have such great strength? First, this product
The thickness reaches 60 ～ 80mm; the second is that the product is added with a special binder when the ingredients are blended; the third is that the product is fired at a temperature of about 1200 ° C. Because the permeable brick
uses ceramics as the material, its firing temperature reaches about 1230 ~ 1250 ℃, and the firing cycle is between
About 20 hours. Therefore, although the porosity of the product is large, the strength is still ensured.
The colors and models of ecological permeable bricks
are various, so that each application unit can customize various pictures, colors, models and sizes. Used in the construction of school pavements, which can better serve the school's landscaping and scene construction. And its rough appearance makes it have strong anti-slip function, and it has certain advantages compared with similar granite floor tiles.
2. Two planning schemes and construction techniques
(I) Economic feasibility issues that need to be considered before planning
Compared with other pavement constructions, university schools have a dense cultural heritage and are a special ecological environment. The construction of pavements needs to be reconsidered. And the school does not have large trucks at all, most of which are teachers' private cars and school buses, so the school's pavement construction has its particularity in terms of pavement strength. Therefore, it is only necessary to build a mini-car route, parking lot, pedestrian route and square pavement, and plan a special route for school buses. This separation construction not only satisfied the demand, but also greatly reduced the cost. The construction methods of the road surface of the school car and the parking lot, as well as the construction methods of the square and the pavement are described in detail below.
School small car road surface and parking lot construction practices (Figure 1)
1.Excavation of subgrade:
According to the requirements of the plan, excavate the roadbed and arrange the earthwork to reach the planned elevation; check the longitudinal slope, cross slope and sidelines to see if they meet the requirements of the plan; repair and compact the roadbed and level the compaction, compaction coefficient More than 95%, pay attention to buried pipelines during construction.
2. Padding: laying 60mm thick medium sand. 3. Laying of the bottom layer: When laying compacted graded crushed stone (particle size 5 ～ 60mm) 200mm thick, the compaction coefficient must be above 93%.
4.Laying of screed layer: To ensure the flatness of the permeable bricks
on the top layer, a 30mm screed layer (gradation with a particle size of 0.3 to 5mm) is used on the bottom layer to spread the data evenly on the bottom layer. , Then use a trowel to hit and smooth.
5. Surface layer laying: The surface layer is permeable brick
. When laying, the permeable brick
is laid according to the plan drawing. When laying bricks, you should lay them quietly and hit them with a rubber hammer to stabilize them, but the corners of the bricks must not be damaged. Lay permeable bricks
should be checked for stability and the surface layer is flat. If you find that the moving parts should be trimmed immediately. The maintenance period after the permeable bricks are
laid shall not be less than 3 days. The quality of sand for joints shall conform to the inspection procedures.
School sidewalk and square pavement construction practices (Figure 2)
1.Excavation of subgrade: According to the requirements of the plan, excavate the roadbed and arrange the earthwork to reach the planned elevation; check the longitudinal slope, transverse slope and sidelines to see if they meet the requirements of the plan; repair and compact the subgrade and leveling rollers For compaction, the compaction coefficient should be above 95%. Pay attention to the buried pipelines during construction.
2. Padding: laying 60mm thick medium sand.
3. Laying of the bottom layer: laying compacted graded crushed stone (particle size 5-60mm) is 100mm thick, and the compaction coefficient must be above 93%.
4.Laying of the screed layer: To ensure the flatness of the permeable bricks
on the top layer, a 30mm screed layer (gradation of 0.3 to 5 mm in particle size) is set on the bottom layer to spread the data on the bottom layer. , Then use a trowel to hit and smooth.
5. Surface layer laying: The surface layer is permeable brick
. When laying, the permeable brick
should be laid according to the plan drawing. When laying the brick
, it should be laid quietly and hit with a rubber hammer to stabilize it, but the corners of the brick should not be damaged. The brick
should be checked for stability and the surface layer is flat. It is found that the active part should be repaired immediately. The maintenance period after laying the permeable brick
should not be less than 3 days. Construction requirements for joint sand: The quality of joint sand should conform to the inspection regulations.
Third, the conclusion
is a new type of environmentally friendly building materials. Its strength is not much different from that of ordinary concrete, and its variety and water permeability are not found in other building materials. Utilizing its common permeable function can alleviate the traffic pressure caused by surface runoff,
At the same time, the rainwater infiltrated the groundwater, which eased the subsidence of the foundation and the severe lack of groundwater caused by the large amount of groundwater excavation. In addition, its production technology and construction technology are both environmentally friendly and economical, and it is the road material for the construction of an aspiring school. Its low noise pollution during construction provided an outstanding learning and living environment for the school. The use of permeable bricks
for the construction of school pavements has truly completed the coexistence and blending of people, environment and nature.