The sidewalk bread brick has excellent water permeability, air permeability, and water retention, and has many functions of cooling, noise reduction, climate conditioning, improving air quality, and maintaining surface water circulation. Because of its appearance, it has dealt with many problems.
The sidewalk bread bricks deal with the problem of road water caused by rain and affecting people's walking. The emergence of permeable bricks has dealt with the problem of groundwater well, and has created conditions for the urban environment and urban landscaping plants. It is used in local sidewalks, stations, pedestrian streets, apartment parking lots, airports and other local bread bricks, replacing cement and stone hardened pavements. It has become a popular paving stone that is widely valued.
Problems and causes of bread paving on sidewalks: ★ Floor tiles arching and bursting: Floor tiles arching and bursting appear briefly in the northern regions, and some areas in the south also have outbreaks during the dry and hot season. The main reasons are: Abrupt change: Outdoor floor tiles are directly affected by the atmospheric environment due to direct contact with the external environment, and are more sensitive to temperature changes. Due to the drastic changes in temperature, the tiles are heated and unevenly expanded, causing the tiles to bulge and burst.
(2) The quality of the floor tile material is unqualified: due to the lack of consistent testing standards, some units often decide whether to buy based on the color and shape of the brick without strength and durability. Some varieties, such as sintered paving slabs, have high compressive strength, but are brittle in texture, and are easily damaged during transportation and handling.
(3) The expansion joints between the floor tiles are too narrow or no joints are installed: especially some outdoor squares and other places use a single floor tile with a large area. When the temperature changes drastically, a single Shubrock brick will undergo thermal expansion. The adjacent gap was too small, and the floor tiles did not have a satisfactory "expansion". The adjacent floor tiles pushed each other and arched briefly, and some even burst and damaged.
(4) Cut corners, the process quality is unqualified, and the construction quality is poor: uneven cement mortar bonding layer or improper mortar mix affects the strength development. For example, two adjacent floor tiles are paved next to the plain soil layer, and a small amount of cement-mortar bonding layer is placed below the other. Due to the large thermal expansion coefficients of the mortar layer and the plain soil layer, the two floor tiles swell Inconsistency and arch burst.
(5) Damage due to improper load during use: Some sidewalk bricks are parked or passed large vehicles or stacked heavy loads. Due to the lack of satisfactory strength in the bottom layer or the failure to pass the upper pressure of the deformation buffer, the floor tiles are widely damaged. ★ Floor tiles are empty and falling: The problems of floor tiles being empty and falling are more extensive than the former. Especially for small sidewalk bricks, such problems often occur. For example, some of the sidewalk bricks just laid in an urban area have some problems. Fractured or separate from the ground.
The reasons may be as follows:
(1) Improper selection of materials, irregular appearance standards of floor tiles, excessive sand content and poor cleaning; or unused medium-sized sand; low cement strength or mixed cement of different varieties and manufacturers, excessive water content of cement mortar Large will also cause too much cement chemistry shortening or leave a lot of void after hardening, reducing the bonding area with facing bricks. As a result, the floor tile on the reverse side of the floor is dropped and cracked and damaged due to stress concentration in some compressions.
(2) When the rigid or semi-rigid bottom layer is selected, the layering of the lime soil is lacking or the thickness is not sufficient; the strength of the bottom layer is too low, and the settlement is uneven when the upper part bears the load. At this time, the mortar bonding layer is easily broken and damaged. When it rains, rainwater is poured into the ground floor from the center of the brick gap, and the floor is covered with standing water. The water penetrates into the fragile floor and forms mud. The floor tile is loose and falls after being pressed. This quality problem is most common in outdoor floor tiles.
(3) There are sundries on the bottom layer; the sundries on the bottom layer have not been cleaned up before applying the mortar, resulting in a weak bonding between the bottom layer and the mortar bonding layer, and the bonding effect of the mortar bonding layer is greatly reduced.
(4) The construction method is incorrect; the floor tiles are watered and wet before paving. The floor tiles are difficult to hydrate and harden due to the absorption of water in the cement mortar: or due to the improper ratio, the amount of cement is relatively small and the strength of the cement mortar bonding layer is lacking. ; The thickness of the mortar leveling layer is uneven; the number of hammer strikes is not enough to constitute a combination that is not strong or the construction temperature is too low. The cement mortar cannot be hydrated and unfolded in time after pouring. The laying operation is not standard, the flatness of the bonding layer is poor, the density is small, and the unevenness is not uniform. The height difference between adjacent bricks is greater than 1mm, maybe one head is wide and the other is narrow, or the bonding layer is partially settled and the height difference occurs.
(5) Unsatisfactory product protection time and protection requirements: due to the condensation and hardening and strength expansion of the cement mortar, certain temperature and humidity are required, and even water retention protection at a certain time is required. Or, if the watering protection or unsealed protection is not carried out in time, the cement mortar will stop the strength deployment.