Application advantages of polycarboxylate superplasticizer and microsilica in UHPC

Application advantages of polycarboxylate superplasticizer and microsilica in UHPC

Keywords
Polycarboxylate superplasticizer, microsilica, UHPC, China polycarboxylate supplier

Ultra-high performance concrete (UHPC) refers to a cement-based concrete material with ultra-strong mechanical properties, high toughness, ultra-high durability and excellent pouring and forming properties. UHPC is formulated by selecting highly active micro-materials and using the tightest bulk and fiber reinforcement technology. High-strength and tough materials such as Portland cement, microsilica fume, quartz powder, fine silica sand, superplasticizer, water, steel or organic fibers are usually used as raw materials.

UHPC contains a large amount of cement, usually high-grade Portland cement or a blended cement with a high proportion of Portland cement. The strength of UHPC mainly comes from dicalcium silicate and tricalcium silicate in the cement components, while tetracalcium ferroaluminate has limited contribution to strength. The hydration reaction of tricalcium aluminate requires high water demand, so it is advisable to try to reduce the iron content.  Contents of tetracalcium aluminate and tricalcium aluminate.

Microsilica fume is an ultra-fine particle that accumulates in the gaps of cement particles to improve the density of UHPC and reduce porosity; silica fume can react secondary with cement hydration products to generate more calcium silicate  Hydrate enhances the strength and durability of UHPC; silica fume can also improve the workability and fluidity of UHPC and reduce defects and stress concentrations within the concrete. Therefore, microsilica powder is irreplaceable in the use of UHPC.

Polycarboxylate superplasticizer is suitable for preparing high-fluidity concrete; Polycarboxylate superplasticizer has become the first choice admixture for preparing UHPC. Polycarboxylate water-reducing agent is a concrete admixture with high water-reducing rate and small slump loss.  It can greatly increase the rheological properties of fresh concrete while increasing the compressive strength of hardened concrete and keeping water consumption unchanged. It plays a vital role in the workability of fresh concrete and hardened concrete. It also ensures the continuity of project construction, greatly shortens the construction period, promotes the development of fluid concrete technology and pumping pouring, and accelerates the development of commercial concrete.