Foam Concrete Highway Subgrade Backfill Project

Key Points for Lightweight Aggregate Concrete Construction Technique

The construction process for lightweight aggregate concrete is essentially the same as that for normal concrete. However, due to the low bulk density, porous structure, and high water absorption rate of the lightweight aggregate, the concrete it forms also exhibits certain characteristics. Attention must be given throughout the construction process to ensure the quality of the project.

Requirements for the stacking and pre-wetting of lightweight materials

Light aggregates should be stacked separately by type and particle size; mixed stacking will directly affect the workability, strength, and apparent density of concrete. When using natural gradation, the stacking height of light aggregates should not exceed 2 meters, and precautions should be taken to prevent the mixing of leaves, soil, and other harmful substances. Measures to prevent rain should be taken during the stacking and transportation of light sand.

Lightweight aggregates have a high water absorption rate, making it difficult to control the workability of concrete mixtures. Therefore, during construction in seasons with temperatures above 5°C, pre-wetting of lightweight aggregates should be conducted. The pre-wetting time should be determined based on the external temperature and the natural water content of the incoming materials, generally requiring 12 to 24 hours of watering and pre-wetting the aggregates before drying them and adding them to the mix. Below 5°C temperatures, or for lightweight aggregates without open pores on the surface, pre-wetting is usually not necessary.