Precautions for construction of pea stone backfilling for floor heating:
1. Strictly control the water cement ratio
The water cement ratio directly determines the strength of mortar. If the water cement ratio is too large, the ground strength is low, the ground surface is rough, not wear-resistant, easy to sand, and the excess free water evaporates. Only fine pores appear in the cement slurry surface, which reduces the compactness of the mortar and is easy to wear and sand. Ordinary portland cement (strength grade not less than 42.5mpa) shall be used as far as possible.
Compared with slag cement and pozzolanic cement, ordinary portland cement has the advantages of good water retention, low dry shrinkage and high early strength, which is beneficial to ensure the ground quality and construction progress. The use of ordinary portland cement is the premise to ensure the strength of mortar and prevent sanding on the floor.
2. It is forbidden to use expired cement and damp cement
The cement stored for more than three months is called expired cement. When the expired cement is used for the ground surface, its strength, hardness and wear resistance will decrease significantly, resulting in sand. Damp cement is that cement and water react and coagulate into blocks, with poor cementation performance. Compared with expired cement, the quality is worse, so it can not be used on the ground surface.
Pea stone backfilling for floor heating
Construction of pea stone backfilling for floor heating
3. Do not use fine sand for ground surface mortar
The ground must bear all kinds of pressure, friction and impact, and must have certain strength and wear resistance. Coarse sand and medium sand are better than fine sand in strength and wear resistance. The mortar mixed with fine sand has large dry shrinkage and is easy to crack. Water retention is also poor, which is not conducive to calendering. The mud content of sand shall not be greater than 3%, otherwise the mortar strength will be reduced, resulting in sand on the floor.
4. Master the calendering time
Calendering shall be completed before final setting. If calendering is too early, a layer of water will float on the surface, which will inevitably affect the strength of mortar; Too late the pressing time will disturb or damage the coagulation structure of cement gel, affect the growth of mortar strength, and the pores of the surface are also difficult to solve, which will also cause sand production.
5. There should be enough maintenance time
The quality of maintenance has a great relationship with the quality of the ground. Generally, the curing time shall be more than 7 days; The curing time is not enough. If the water evaporates continuously in the dry air, the hardening will slow down or even stop, the surface mortar will not reach the design strength, and sanding is inevitable. Similarly, if it is used too early when the strength is low, it is bound to interrupt the maintenance, affect the strength growth, and the surface course will be damaged.
The above is the detailed introduction of Jinan floor heating. I hope it will help you If you have any questions, please contact us We will provide you with professional service http://www.jn-langkun.com