Microfibrillar Cellulose Admixture for Concrete Segregation Control

The patent introduces a stabilizing admixture comprising microfibrillar cellulose and/or its derivatives as an intermediary substance. This admixture forms a hydrogel network that acts as a mediator between water and cement particles, providing structural support to the grout mixture. The hydrogel network prevents water segregation and aggregate settlement while maintaining high fluidity, thus resolving the contradiction between ease of operation and compositional stability.

The patent creates a composite system by combining microfibrillar cellulose, its derivatives, or labile chemically modified cellulose pulp with cement and water. This composite admixture forms a unique hydrogel network structure that integrates the properties of cellulose fibers and water, providing both fluidity and stability simultaneously. The composite nature of the admixture allows it to function as both a fluidity enhancer and a segregation inhibitor.

The stabilizing admixture acts as an intermediary hydrogel network that provides internal structural support to the self-compacting concrete mixture. This network mediates between the competing requirements of high flowability (for productivity) and compositional stability (to prevent segregation). The hydrogel structure allows the concrete to flow and compact itself while maintaining uniform distribution of components throughout the mixture.

The patent modifies the rheological parameters of the concrete mixture by introducing the microfibrillar cellulose-based admixture. This changes the flow behavior and thixotropy of the mixture, allowing it to maintain stability during the self-compaction process. The admixture adjusts the physical parameters of the fresh concrete to achieve both high productivity and reduced segregation sensitivity.

The patent changes the physical state and structural parameters of the cellulose-based additive by using microfibrillar forms with diameters less than 1 μm (preferably less than 200 nm, more preferably less than 100 nm). This parameter change in fiber dimensions dramatically increases the surface area and networking capability per unit mass, allowing much lower dosages (0.002-0.2% by weight of cementitious binder) to achieve the same or better segregation control compared to conventional cellulose derivatives that require higher dosages.

The patent creates a highly efficient composite structure using microfibrillar cellulose that forms a three-dimensional hydrogel network. This composite network structure provides exceptional segregation control at very low concentrations because the microfibrils create a more extensive and effective spatial framework compared to larger cellulose fibers or conventional viscosity modifiers. The composite nature of the hydrogel network maximizes the stabilizing effect per unit of additive.