Straight Pore Cement Pavement Resolving Strength Drainage Trade-off

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Solution Overview

Problem

Existing permeable concrete pavements suffer from clogging due to high tortuosity of the pore network, leading to reduced drainage efficiency and the need for frequent maintenance, and they lack the mechanical strength for heavy traffic applications.

Innovation Solution

A method of forming a cement-based material pad with a plurality of straight conduits to create low tortuosity drainage holes, ensuring high permeability and strength by using forms with parallel conduits and a cement-based material poured around them, which can be cast on-site or in pre-cast blocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional permeable concrete uses high porosity to achieve sufficient permeability, then drainage capability is improved, but compressive strength deteriorates and the material becomes restricted to light traffic applications

Engineering Contradiction:
Improvedrainage capabilityVSAvoidcompressive strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention segments the pore structure into two distinct types: large vertical channels (10-50mm diameter) for primary water transport and smaller interconnecting pores (1-10mm diameter) for secondary drainage. This segmentation allows the large channels to carry the bulk of water flow with minimal clogging risk, while the smaller pores provide additional drainage capacity, thereby maintaining high permeability without requiring the entire structure to be highly porous, thus preserving compressive strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by creating regions of high porosity (around the large vertical channels) and regions of lower porosity (the cement matrix). The large channels provide localized high-flow paths where porosity is maximized, while the surrounding cement matrix maintains sufficient density and strength. This spatial variation in porosity allows the material to achieve high overall permeability through the channel network while maintaining structural integrity in the matrix regions.

Inventive Principle:
Principle #3Local quality

2Reliability

If permeable concrete has high tortuosity pore network to provide porosity, then permeability is improved, but clogging resistance deteriorates due to variable path cross-sections and random interconnectivity

Engineering Contradiction:
ImprovepermeabilityVSAvoidclogging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention introduces asymmetry in the pore structure by creating predominantly vertical channels with consistent cross-sections rather than the symmetric, random pore network found in conventional permeable concrete. The vertical orientation and uniform diameter of the large channels (10-50mm) create asymmetric flow paths that minimize tortuosity and eliminate narrow constrictions, thereby maintaining high permeability while preventing particle accumulation and clogging.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention inverts the conventional approach to pore structure by instead of relying on random interconnecting pores, it creates a structured network of straight vertical channels. This inversion transforms the pore architecture from a chaotic, high-tortuosity system to an ordered, low-tortuosity system, fundamentally changing how water flows through the material and eliminating the clogging mechanisms associated with random pore networks.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If permeable pavement is designed for high porosity to maintain permeability throughout service life, then drainage efficiency is improved, but mechanical properties deteriorate and frequent maintenance is required

Engineering Contradiction:
Improvepermeability retentionVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention applies preliminary action by pre-forming the large vertical channels within the cement matrix before final curing. These channels are created using formwork or void-forming elements during the casting process, ensuring that the high-permeability pathway structure is established before the material is subjected to service conditions. This preliminary structuring of the pore network ensures that permeability is locked in at high levels from the outset, eliminating the need for later maintenance to preserve drainage capacity.

Inventive Principle:
Principle #10Preliminary action

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 resulting high-strength clogging-resistant permeable pavement maintains porosity and permeability without frequent maintenance, effectively addressing urban flooding and enabling use in heavily loaded areas.

Implementation Method 1

the conduits create a plurality of straight pores through the cement-based material

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

maintains porosity and permeability for storm-water infiltration

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP3880887B1High strength porous cement-based materials
Publication Date: 2025.04.02 IMPERIAL COLLEGE INNVOATIONS LTD
  • EP3880887B1 patent drawingFigure 1~2
  • EP3880887B1 patent drawingFigure 3~4
  • EP3880887B1 patent drawingFigure 5

AI summary

The present disclosure is related to a method of forming a cement-based material pad comprising a plurality of drainage holes and forms for use in such a method.