BXHT-53  Silicone Caulking Sealant

(Suitable for use in High-speed Railway project ) 

 

I. Product Description：

BX-53 high-speed railway silicone caulking sealant is a high-performance caulking sealant specially developed by our company for properly sealing the expansion joints in construction and maintenance of concrete railway substrate and concrete railway platform. It is applicable to the joints on high-speed railway unballasted track base plate, track-bed slab and tracks.

This silicone caulking sealant is characterized with high adhesion, high temperature resistance, low temperature resistance, ultraviolet resistance, ozone resistance, high flexibility and shear resistance, as well as low modulus, high elasticity and long service life. Far better than the polyurethane caulking sealant and asphalt-based caulking sealant which are easy to age, this silicone caulking sealant is subject to one-component packaging, and ready for cold construction, which is simple and workable. It is environment-friendly and cost-efficient, so its engineering cost is also lower than that of the polyurethane and asphalt-based caulking sealant. Many successful cases have proved that this sealant is the most ideal weather-resistant concrete caulking sealant. It has been used in the construction of  high-speed railway projects.

 

 

II. Typical Performance Parameters

No.	Item		Unit	Specifications
1	Tack free time		min	≤60
2	Mass loss rate		/	≤5%
3	Slump(70℃)	Applied vertically	mm	≤3

 

 

 

 

 

 

 

 

 

 

 

 

		Applied horizontally	mm	0
4	Elastic recovery（tensile stress at 150% elongation）		/	≥80%
5	100% Tensile modulus	Temperature：23℃	MPa	≤0.3
		Temperature：-20℃	MPa	≤0.3
6	Tensile strength	Temperature：23℃	MPa	≥1.0
		Temperature：-20℃	MPa	≤2.0
		Thermal aging（80℃）for 336h	MPa	≥0.8
		Alkali treatment for 336h	MPa	≥0.8
		Ultraviolet aging for 1500h	MPa	≥0.8
7	Elongation at break	Temperature：23℃	/	≥800%
		Temperature：-20℃	/	≥600%
		Thermal aging（80℃）for 336h	/	≥600%
		Alkali treatment for 336h	/	≥600%
		Ultraviolet aging for 1500h	/	≥600%
8     8	Tensile properties at maintained extension （150%）	Temperature：23℃	/	Intact
		Temperature：-20℃	/	Intact
		Thermal aging（80℃）for 336h	/	Intact
		Immersion in water for 192h	/	Intact
9	Adhesion after cold drawing and hot pressing		/	Intact
10	Adhesion after stretching and compressing cycle		/	Intact

 

 

 

 

 

 

 

 

III. Characteristics of Product

Single-component sealant curing at ambient temperature —Directly injecting the sealant into joints without heating and mixing it, which is highly workable;

High elasticity—Adaptive to the significant expansion and contraction of joints;

Low modulus —Highly flexible at low stress, with persistent bonding surface; Excellent high and low temperature resistance—Showing desirable elasticity at -40 ℃, without  fluidity and degradation at 150 ℃ high temperature;

Incomparable anti-aging properties —The silicone caulking sealant has high Si-O-Si bonding, so it is difficult to be degraded by UV and ozone; it retains high flexibility and strength subjected to 1500 hour’s artificial aging test. In natural environment the sealant can last two decades without damage.

IV. Usage

1. On-site adhesion test: Considering the diversity of concrete ingredients and different cleanliness of joint surface, it is recommended to perform on-site adhesion test before large-scale construction in order to develop a reasonable construction plan.

2. Estimate of sealant consumption: Theoretically, for the joints 20mm in width requiring 20mm thick sealant, 1 L sealant can be applied about 2.5m; for the joints 15mm in width requiring 15mm thick sealant, 1 L sealant can be applied about 4.4m.

3. Caulking Procedures

(1) Cleaning joints: Remove the dust, gravel, foam or scrapped caulking materials from the joints, and take the necessary measures to make the joints clean and dry. Request the relevant inspectors to check the joints cleaned before proceeding construction;

(2) Inlaying strips: Measure the width of the joint, and select the foam strips of appropriate size; install the strips to the specified depth with tools.

(3) Applying interfacial agent: For the concrete exposed to heavy dust, apply interfacial agent on inside surface of the joints to improve the adhesion between the sealant and concrete.

 

 

 

 

 

 

(4) Injecting sealant: Continuously injecting an appropriate amount of silicone caulking sealant into joints, and press the sealant even to ensure that the caulking sealant is continuous and full in the joints, free of holes and defects, which can be rechecked by the relevant inspectors;

(5) Curing: At room temperature and normal humidity, wait for 2 to 3 hours and the

sealant will be tack free; wait for 24 to 48 hours and the sealant will be completely cured. Under normal circumstances, the sealed joints can be accepted after the sealant is fully cured. Under special circumstances, the sealed joints can be accepted after the sealant is tack free.

V. Product Maintenance

In normal conditions, the silicone caulking sealant subjected to natural aging almost experiences no damage to its sealing effect, so it is almost maintenance free. However, in case the silicone caulking sealant is destructed by some unexpected factors, it is necessary to re-seal the joints. The joints shall be cleaned, free of dirt and direct sealed with this silicone caulking sealant. This product can be well adhered to its own cured layer.

VI. Product Packaging, Shelf Life and Precautions

This product is sold in 0.75kg composite flexible package (about 600ml), and 20 packages in one box, which has a net weight of 15kg.

Its shelf life is 12 months. The sealant beyond shelf life can be used only if it is tested to cure and produce adhesion as required.

This product shall be stored in a cool, dry and ventilated place.

This product is for industrial purpose only, so it shall be kept out the reach of children. Before curing, avoid direct contact with eyes or bare skin. When curing, this product will release a slight amount of low-molecular weight substances and smell, so apply this silicone caulking sealant in tailwind. Do not eat, drink or smoke on construction site. It is necessary to clear the construction tools and construction site, and remove the debris after the construction is completed.