- Apr 01, 2018 -
In many concrete projects, traditional high-efficiency concrete such as naphthalenes can not meet the engineering needs more and more because of the limitations of technical performance. A new generation of water-reducing agent, polycarboxylic acid-based high performance water-reducing agent attracting attention at home and abroad, because it truly achieves an effective molecular structure based on the action mechanism of dispersed cement, has an ultra-dispersed type, and can prevent concrete slump loss. It does not cause significant retardation, gives a high plasticizing effect at low dosages, maintains good fluidity, has a large degree of freedom for cements to adapt to wide molecular structures, has a large amount of synthetic techniques, and has high performance. Significant effect, can reduce concrete shrinkage, extremely low hazardous material content and other technical performance characteristics, gives concrete excellent construction workability, good strength development, excellent durability, polycarboxylic acid series high performance water reducer has good Comprehensive technical performance advantages and environmental characteristics, in line with the needs of modern concrete projects. Therefore, polycarboxylate superplasticizers are gradually becoming the first choice of additives for the preparation of high performance concrete. According to reports, the use of Japan's polycarboxylic acid admixtures has accounted for more than 80% of all high-performance admixture products, and North America and Europe also accounted for more than 50%. In China, polycarboxylate water reducers have been successfully applied to large-scale water conservancy, bridges, nuclear power, and railway projects in the Three Gorges Dam, Sutong Bridge, Tianwan Nuclear Power Station, and Beijing-Shanghai High Speed Rail, and have achieved remarkable results.
At the same time, polycarboxylate water reducer also has some problems: 1. The lack of moisture retention in high temperature environment; 2. The temperature sensitivity, the same kind of polycarboxylate water reducer construction in different seasons, the concrete protection of a far cry; 3. Less functional products, it is difficult to meet the requirements of ultra-high, ultra-long distance concrete pumping, negative temperature construction, ultra-early-strength concrete preparation and high durability of concrete; 4. High viscosity, high blending material, low In the preparation of concrete with water/rubber ratio, the concrete has a high viscosity and is not conducive to construction. 5. It is sensitive to the mud content of gravel aggregates. 6. The adaptability to the machined sand is also poor, and the quantity sensitively affects the construction.