中国粉体技术2025，Vol.31Issue(5)：145-154,10.DOI:10.13732/j.issn.1008-5548.2025.05.012
石灰和粉煤灰掺量对再生骨料-生土复合材料耐久性能的影响
Effects of lime and fly ash dosage on durability of recycled aggregate-raw soil composite
摘要
Abstract
Objective Raw soil has low strength and poor durability,but it offers advantages such as recyclability,good thermal perfor-mance,and ease of construction.The strength and durability of raw soil can be improved through chemical modification by active materials such as cement,gypsum,lime,and fly ash.The strength of raw soil can be improved through physical modification by recycled aggregates made from crushed and screened waste concrete,bricks,etc.Therefore,to fully utilize raw soil in modem construction industry,lime and fly ash are needed to blend into recycled aggregate-raw soil composite to improve durability. Methods The mass fractions of raw soil,recycled fine aggregates,and recycled coarse aggregates were set at 60％,10％,and 30％,respectively.The mass of water was set to 14％of the total mass of the three raw materials.After mixing the three raw materials,water was added to produce the initial specimen of recycled aggregate-raw soil composite.Chemical modification was carried out by adding different dosages of lime and fly ash,with lime mass fractions set at 6％,7％,7％,8％,and 8％,and fly ash mass fractions set at 12％,12％,13％,13％,and 14％,respectively.Through water resistance,erosion,wet-dry cycling,and freeze-thaw cycling tests,the water resistance,erosion resistance,wet-dry cycling resistance,and freeze-thaw resistance of the recycled aggregate-raw soil composite were analyzed.X-ray diffraction and scanning electron microscopy were used to characterize the hydration products and microstructure of the recycled aggregate-raw soil composite. Results and Discussion With the increase in lime and fly ash dosage,the softening coefficient of the specimens increased,and the water resistance was gradually enhanced.When the lime mass fraction was 8％and the fly ash mass fraction was 14％,the recycled aggregate-raw soil composite specimen exhibited the highest softening coefficient and the best water resistance.Its erosion resistance was significantly improved with an erosion resistance time of up to 60 minutes.The specimen had the smallest mass loss rate.After 15 wet-dry cycles,both the mass loss rate and compressive strength loss rate were at their minimum values,showing the best resistance to wet-dry cycles.After 25 freeze-thaw cycles,the mass loss rate of the specimen was less than 5％and the compressive strength loss rate was less than 25％,demonstrating the best freeze-thaw resistance of the recycled aggregate-raw soil composite specimen. Conclusion The alkaline effect of lime activates the reactive substances(SiO2,Al2O3)in the raw soil,fly ash,and recycled micro powder,participating in the hydration reactions to generate C-S-H gel,C-A-S-H gel,Ca(OH)2 crystals,and calcium vanadate crystals.These hydration products fill the cracks and pores within the recycled aggregate-raw soil composite,enhanc-ing the adhesion between the particles and improving the durability of the recycled aggregate-raw soil composite.关键词
再生骨料-生土复合材料/石灰/粉煤灰/耐久性能/微观结构Key words
recycled aggregate-raw soil composite/lime/fly ash/durability/microstructure分类
通用工业技术引用本文复制引用
何晓,周文娟,刘洋,段珍华..石灰和粉煤灰掺量对再生骨料-生土复合材料耐久性能的影响[J].中国粉体技术,2025,31(5):145-154,10.基金项目
国家重点研发计划项目,编号:2022YFC3803403. （）
