Pigmented Aggregate Colorfastness via Microbial Calcite Bonding
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Solution Overview
Problem
Current methods for producing colored cement compositions face issues such as pigment dispersion leading to leaching, color inconsistencies, and the need for repeated painting due to pigments not adhering well to aggregate surfaces, resulting in limited color options and durability.
Innovation Solution
A method involving microbial-induced calcite precipitation (MICP) where pigments are adhered to aggregate surfaces at ambient temperatures, forming a stable calcite bond that enhances color intensity and durability, allowing for a wide range of colors and patterns without leaching, and achieving colorfastness comparable to or exceeding traditional painted structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pigments are dispersed throughout the fluid cement composition, then color can be applied to the cement, but the pigment leaches while the cement is hydrating and color differences occur between batches
Solution Approach 1:
The pigment is applied to the aggregate surface before the cement is mixed and placed. This preliminary action ensures the pigment is in position before hydration occurs, preventing leaching and color inconsistency. The aggregate acts as a carrier for the pigment, securing it in place before the cement matrix forms.
Solution Approach 2:
The aggregate serves as an intermediary between the pigment and the cement matrix. By applying pigment to the aggregate surface rather than dispersing it in the cement slurry, the aggregate mediates the pigment's interaction with the cement, preventing direct contact that would cause leaching during hydration.
2Manufacturing precision
If pigments are dispersed in the cement composition, then color can be achieved, but the pigments float to the surface and do not provide uniform color distribution
Solution Approach 1:
The pigment is applied to the aggregate surface in advance, before mixing with cement. This ensures uniform distribution is achieved during the simple mixing process rather than requiring stable dispersion in the fluid cement slurry, eliminating floating and color inconsistency.
3Duration of action of stationary object
If traditional painting methods are used to color masonry, then color can be applied, but repeated painting is required to maintain color integrity
Solution Approach 1:
The pigment is applied to the aggregate surface during the initial manufacturing process, before the masonry is installed. This preliminary coloring action integrates the color into the structure itself, eliminating the need for repeated surface painting and maintenance throughout the service life of the masonry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces colored solid structures with enhanced colorfastness and durability, maintaining color integrity for the useful life of the masonry, which can simulate natural materials like stone, and offers improved hardness and load-bearing capabilities comparable to traditional construction materials.
Implementation Method 1
The mixture is incubated to promote MICP, thereby forming bonds between the aggregate particles
Implementation Method 2
The pigment is adhered to aggregate surfaces
Data Source
AI summary
The invention is directed to compositions and methods for the manufacture of pigmented solids structures for which can be used for construction and/or decoration. Manufacturing comprises fixing one or more pigments to an aggregate material such as crushed rock, stone or sand. The pigmented aggregate is incubated with urease or urease producing microorganisms, an amount of a nitrogen source such as urea, and an amount of calcium source such as calcium chloride forming calcite bridges between particles of aggregate. The resulting solid has a hardness and colorfastness for most any construction material. Using selected aggregate and pigment, the process also provides for the manufacture of simulated-stone materials such as clay or granite bricks or blocks, marble counter-tops, and more. The invention is also directed to composition containing microorganisms and pigment as kits that can be added to most any aggregate materials.