Effect of water consumption on the performance of polycarboxylic acid concrete mixture
The influence of water consumption is very obvious. In the actual application of concrete engineering, sometimes if the water consumption increases by 1 ~ 3kg / m3, the concrete will have serious bleeding phenomenon, which will cause pitting, sanding, holes and other defects on its surface, and the uniformity and construction quality of concrete pouring cannot be guaranteed, resulting in the reduction of the strength and durability of concrete structure.
Polycarboxylic acid concrete is prone to delamination and segregation
In most cases, adding polycarboxylic acid water reducer to concrete will greatly reduce the viscosity of the slurry. At the same time, even if the dosage and water consumption of polycarboxylate superplasticizer are the best and there will be no bleeding, the concrete is prone to delamination and segregation, which is mainly reflected in the separation of coarse aggregate from mortar and net slurry and a large amount of subsidence. This kind of concrete mixture has no vibration when pouring concrete works, and the phenomenon of delamination and segregation is also very obvious.
Poor compatibility
Naphthalene series, aliphatic series, lignosulfonate, aminosulfonate and other traditional water reducing agents can be mixed in any proportion, so as to meet the preparation requirements of various concrete. These traditional water reducing agents can not only dissolve each other in water, but also achieve excellent superposition effect when used in combination. Polycarboxylic acid water reducing agent has great limitations and can only be used in combination with traditional water reducing agent lignosulfonate, which has poor compatibility with other traditional water reducing agents. If it is combined with other types of traditional water reducing agents, it will not only be difficult to achieve the superposition effect, but also make the fluidity of concrete very poor. With the significant increase of water consumption, the serious loss of slump and the dry and difficult unloading of concrete, the strength and durability of concrete will be seriously affected.