# Low-Carbon, Low-Shrinkage Concrete Design Based on Paste–Aggregate Binary Model

## TL;DR

This paper introduces a new method for designing concrete that reduces carbon emissions and shrinkage by optimizing the paste-aggregate mix.

## Contribution

A performance-based concrete mix design methodology using a paste-aggregate binary model to reduce binder content while maintaining workability and strength.

## Key findings

- Inter-particle spacing and paste rheology jointly govern fresh concrete behavior, with slump increasing nonlinearly with SPT.
- A two-level strength model predicts concrete strength from paste properties with high accuracy (R2 = 0.90).
- Fixing SPT at 25 µm optimizes flowability with minimal paste volume, enabling sustainable concrete design.

## Abstract

This study presents a performance-based concrete mix design methodology rooted in the paste–aggregate binary framework, aiming to reduce binder content while ensuring optimal workability and strength. We found that inter-particle spacing (SPT) and paste rheology jointly govern fresh concrete behavior, with slump increasing nonlinearly with SPT and a critical transition zone around 20–35 µm; paste yield stress controls slump, while plastic viscosity governs segregation resistance. A two-level strength model was developed to predict concrete strength from paste properties based on compactness and hydration (R2 = 0.90). Fixing SPT at 25 µm was identified as optimal for achieving balanced flowability with minimal paste volume. This approach effectively decouples aggregate packing optimization from paste calibration, offering a physically interpretable and practical framework for designing sustainable, low-carbon, and low-shrinkage concrete.