some problems in the application of polycarboxylate superplasticizerii
Compatibility of polycarboxylate superplasticizer with other admixtures.
Beijing Dongke United Technologies Co.,Ltd.
Polycarboxylic acid water reducing agent is an effective water reducing agent and cement dispersant in cement concrete applications. It is widely used on roads, bridges, levees, tunnels, skyscrapers and other projects.
The water reducing agent is environmentally friendly, non-flammable, explosive and can be safely transported in trains and cars.
According to body structure differences, polycarboxylic acid superplasticizer products can be divided into two categories: one type uses acrylic acid or methacrylic acid as the backbone and grafts polyethers with different side chain lengths.
Others are polyethers whose primary bond is maleic anhydride and have different side chain lengths. Based on this, several high performance polycarboxylate ether superplasticizer products with different properties have been derived.
Prior to the formation of the polycarboxylate water-reducing agent, it was necessary to regenerate the supernatants from the polycarboxylate supernatants.
It has the advantage of low dosage, good droplet retention, low concrete shrinkage, high molecular structure controllability and high potential for high performance. Significant advantages such as the absence of formaldehyde in the process.
For the synthesis of a water reducing agent of a polycarboxylate dehydrating agent, the design of the molecular structure is very important, including the backbone group, the side chain density and the side chain length in the molecule.
The synthesis processes mainly comprise a process of grafting by in situ polymerization, first a process of polymerization then of functionalization, and a process of direct copolymerization of the monomers.
In many concrete projects, traditional high efficiency concretes, such as the naphthalene series, are increasingly unable to meet the needs of the project due to technical performance constraints.
The new generation water reducing agent which attracted much attention at home and abroad, high performance water reducing agent polycarboxylate water, because it really designed effective molecular structure based on a distributed cement mechanism, is superdispersed.
Type and can avoid concrete slump without noticeable delay, as it can provide higher softening effect with low concentration, good flow retention, high degree of cement freedom to adapt to different synthesis techniques molecular weight and high space shrinkage. , good strength development, excellent durability and an effective polycyclic acid water reducing agent.
Arboxylic has good comprehensive technical advantages and environmental protection properties that meet the needs of modern concrete technology. Therefore, polycarboxylate ether superplasticizer high performance water reducing agents are gradually becoming a preferred mixture for the production of high performance concretes.
According to reports, the use of polycarboxylic acid additives accounted for over 80% of all high performance additive products in Japan and over 50% in North America and Europe.
In my country, polycarboxylate water reducing agents have only been successfully used in the Three Gorges Dam, Sutong Bridge, Tianwan Nuclear Power Plant, Beijing-Shanghai High-speed Rail and other large national water protection systems, bridges, nuclear energy and railways. projects that produce significant results.
Compatibility of polycarboxylate superplasticizer with other admixtures.
Polycarboxylic acid high-efficiency water reducing agent is characterized by low dosage and high water reducing rate.
Polycarboxylic acid water reducing agent with high efficient water reducing performance is often used in construction concrete.
Polycarboxylate superplasticizer is a new generation of water-reducing agent based on modified polycarboxylic acid.
Polycarboxylate (PCE) superplasticizers are known as high range water-reducing admixtures in concretes, such as ready-mix concretes, self-compacting concretes (SCC), ultra-high strength concretes (UHPC) and at the same time give an extended slump retention.
The polycarboxylic acid-based high-performance water-reducing agent, has truly designed an effective molecular structure based on the mechanism of dispersed cement. It has a super-dispersed type and can prevent concrete slump loss.