What is a cement blanket?
Cement blanket is a kind of soft cloth impregnated with cement. When it meets water, it will hydrate and harden into a very thin waterproof and fire-resistant durable concrete layer. Cement blanket is woven by polyethylene and polypropylene filament into three-dimensional fiber composite structure (3D fib)
MatrIX, dry concrete mix with special formula. The main chemical composition of calcium aluminate cement is A2O3, CaO, SiO 2, Fe2O3. The bottom of the canvas is covered with polyvinyl chloride (PVC) lining to ensure that the cement blanket is completely waterproof. In site construction, there is no need for any concrete mixing equipment, as long as the concrete blanket is simply watered or immersed in water to cause hydration reaction. After solidification, fibers play a role in strengthening concrete and preventing cracking.
At present, cement blankets have three thicknesses: 5mm, 10mm and 30mm.
Main characteristics of cement blankets
1) Easy to use
Cement blankets can be supplied in large volumes in bulk. It can also be provided in rolls to facilitate manual loading, unloading and transportation without large lifting machinery. Concrete is prepared according to scientific proportioning, without on-site preparation. Excessive hydration will not occur. Cement blankets can be solidified in both underwater and seawater.
2) Rapid Solidification Molding
Once the hydration reaction occurs, the size and shape of the cement blanket can still be processed within 2 hours. Within 24 hours, it can harden up to 80% of the strength. According to the special requirements of users, special formulation can be used to achieve the purpose of rapid or delayed solidification.
3) Environmentally friendly
Cement blanket is a low-quality and low-carbon technology. In many applications, the amount of materials used is at most 95% less than that of common concrete. Its alkali content is limited and scouring rate is very low, so it has little impact on local ecology.
4) Flexibility of application
Cement blankets have good drapability and can conform to the complex shape of the object surface covered, or even form a hyperboloid shape. Cement blankets before solidification can be cut or cut at will by ordinary hand tools.
5) High strength of materials
The fibers in the cement blanket can enhance the strength of the material, prevent cracking, absorb impact energy and form a stable failure mode.
6) Long-term durability
Cement blanket has good chemical resistance, resistance to wind and rain erosion, and no ultraviolet degradation in sunlight.
7) Waterproof characteristics
The bottom of the cement blanket has a waterproof layer, which makes it completely waterproof and enhances the chemical resistance of the material.
8) Fire protection characteristics
Cement blankets do not support combustion and have good flame retardant properties. When ignited, the smoke is very small and the emission of dangerous gases is very small. Cement blankets have reached the B-s1 and d0 levels of the European standard for flame retardant building materials.
cement canvas is a new product with revolutionary materials called Geosynthetic Cementitious Composite Mats used as an alternative to conventional concrete. It is a flexible, concrete filled geotextile that hardens on hydration to form a thin, durable, waterproof and low-carbon concrete layer.Essentially, it's concrete on a roll.
1) Physical properties
|Product modle||thickness mm||Area of small roll sq.m.||Area of big roll sq.m.||Width of roll m||Not solidified mass kg/sq.m.||Not solidified density kg/Cubic meters||Solidified density kg/Cubic meters|
2) Solidification time
Initial solidification (> 120 minutes) and final solidification (< 240 minutes).
The strength of cement blanket can reach 80% 24 hours after hydration reaction.
3) Hydration reaction
Cement blankets can be hydrated with brine or non-brine. The minimum weight ratio of water to cement blanket is 1:2. Cement blankets do not have excessive hydration reaction, so it is always recommended to use excessive water. Water can be sprayed on the surface of the fiber several times until the cement blanket is saturated. Because cement blankets absorb moisture, they first darken and then become lighter. When water gathers or flows down the surface
It shows that the cement blanket is saturated with water.
After the initial hydration reaction, the cement blanket should be re-wetted at least once between one and two hours.
In high temperature and dry weather, this is especially necessary, because water evaporation can cause excessive drying of concrete.
The product HJ008 cement blanket is the most prone to excessive drying. Regardless of the weather, one or two hours after hydration reaction, it should be re-wetted once or more. Do not spray water directly on the cement blanket with high-pressure water spray gun, otherwise it will flush the surface of the cement blanket into a groove shape. If the cement blanket is not adequately protected by water, solidification will be delayed and material strength will decrease. If the solidification time is delayed, a large amount of water should be used to re-wet. Cement blankets can be used underwater, at this time, because immersion in water, can fully occur hydration reaction.
The initial strength of cement blanket is very high, which is the basic characteristic of this material. Typical strength and physical characteristics are as follows
(1) Compressive strength test according to ASTM C47307 standard
- 10-day compression failure stress 40MPa
Ten-day compression Young's modulus 1500MPa
(2) Bending test according to BSEN12467:2004 standard
- 10-day bending failure stress 34MPa
- 10-day bending Young's modulus 180 MPa
(3) Wear resistance test according to DN52108 standard
The wear resistance of ceramics is similar to that of ceramics up to 0.10g/cm2.
(4) Mohs hardness 4-5
CRB puncture resistance according to EN ISO12236:2007 standard (HJ008 only)
- Minimum thrust penetration force 2.69Kn
- Maximum deflection peak 38mm
Resistance to vehicle loading according to EN1991-1-1:2002 standard (H008 only)
- meets class G requirements
- Gross Weight of 2-axle Vehicles 30-160Kn
- Uniform distribution of loads not exceeding 5 kN/m2
According to ASTM G13 pipeline anti-impact Standard Test method passed
_According to BSEN12467:2004 Standard Section 5.52 Freeze-thaw Test Passed
_According to BSEN12467:2004 Standard Section 5.5.5 Immersion-drying test passed
_The water-saving permeability test was passed according to BSEN12467:2004 standard 544.
_Polyvinyl chloride bottom liner thickness 042 mm, moisture permeability 0836-0924 gmmm2 days
_2 Cement blanket static pressure head < 3000mm
---Cement Canvas Installation Guide--
1, preparation work: First, we must plan and measure to ensure a certain slope so that the water flow can flow smoothly from the upper end to the lower end. Secondly, after the construction site is cleaned and leveled, the construction line is set according to the design drawing, and the drainage slope is re-measured.
2, excavation: Set the construction line according to the design requirements, the sides of the ditch need to be leveled, and the slope inside the ditch must not have any virtual soil and empty holes. It is necessary to treat the water damage parts in a tamping manner, except for debris and gravel in the slope. If necessary, use ash soil for compaction treatment, or grouting and reinforced to seal, and the treated parts are required to have good stability.
3, laying The material can be laid vertically and horizontally. Be sure to level the substrate, otherwise, it will affect the appearance quality!
4, seam processing:
4.1. The lateral width of the adjacent two cement blankets is 10cm wide and the depth is doubled.
Place the cement blanket joint at the stack and flatten it.
4.2. Press the cement blanket above the cement blanket in the direction of the water flow, and the superimposed area shall not be less than
4.3 Evenly apply sealant at the seam.
4.4 Fix two pieces of cement blanket with 5*38mm stainless steel screws
4.5 groove along with the treatment
Fix the edge of the material on the edge of the groove with rivets, and fix it with rivets, fix it and use it. The soil covers the edge
4.6 watering solidification
Before the watering, it is necessary to inspect and check the whole of the laying. After passing the water, it can be watered! It needs to be watered 9kg (thickness is calculated in 10m) to be poured, and it must be poured less, evenly from the edge to the middle. Sprinkle water, preferably by spraying, the flow rate is 4000ml/min until the color of the cement blanket becomes darker. Do not use a water column with a high pressure! Do not step on the water after pouring water. When the temperature is ≤ 5 °C, take insulation measures. When the average temperature of day and night is higher than 30 °C, the surface should be covered with plastic film or geotextile, etc. Keep wet, watering and curing time should not be less than 3 days