Development and Promotion of Concrete Strength at Initial 24 Hours

Area of Science:

• Civil Engineering
• Materials Science
• Construction Management

Background:

• Early concrete strength development is crucial for efficient construction processes, including formwork circulation.
• Understanding early-age strength gain is vital for optimizing construction timelines and precast manufacturing.

Purpose of the Study:

• To investigate the early-age strength development of concrete (under 24 hours).
• To evaluate the impact of silica fume, calcium sulfoaluminate cement, and early strength agents on concrete strength at various temperatures (10-30 °C).
• To assess the microstructure and long-term properties of concrete modified for early strength gain.

Main Methods:

• Experimental investigation of concrete strength development at early ages (under 24 hours).
• Testing concrete specimens at ambient temperatures ranging from 10 °C to 30 °C.
• Analysis of microstructure and long-term properties of the concrete mixes.

Main Results:

• Concrete strength exhibits an initial exponential increase followed by a logarithmic rise, contrary to common assumptions.
• Increased cement content showed a noticeable effect only above 25 °C, with marginal strength gains.
• Early strength agents significantly enhanced concrete strength, particularly at lower temperatures and earlier ages.

Conclusions:

• The study provides insights into concrete strength gain dynamics in the first 24 hours.
• Early strength agents are effective in accelerating concrete strength development without adverse effects.
• Findings can inform decisions on optimal formwork removal timing in construction projects.