<p>This study focuses on the collaborative innovation of building solid waste recycling and road- bed lightweight. Aiming at the key technical bottlenecks of high energy consumption and low utilization rate of building micro-powder of traditional foam concrete cementitious materials, this paper mixed 30%, 50% and 70% hybrid recycled micro-powder to prepare A07 density grade foam concrete, and explored the influence of hybrid recycled micro-powder content on the performance of foam concrete. A07 density grade foamed concrete with 70% mixed recycled fine powder was prepared by using composite microbial foaming agent to explore the optimal proportion of mixed recycled fine powder (recycled brick powder:recycled concrete powder is 2:8,4:6,6:4,8:2) in the field of subgrade filling, promote the recycling of mixed recycled fine powder of construction waste, and provide new filling materials with light weight, high strength and ecological benefits for subgrade engineering, which has important engineering application value for promoting the construction of ‘no waste city’. The research results show that: (1) With the increase of recycled micro powder content to 70%, the dry density of A07 grade foam concrete shows an upward trend, and the compressive strength shows a gradual downward trend. The dry density of foam concrete in BP, CP, RP (4:6), RP (6:4) groups increased by 45.5%, 32.7%, 36.9%, and 42.3% respectively compared with the control group, and the compressive strength decreased by 70%, 66%, 55%, and 64% respectively; (2) The performance of hybrid recycled micro powder foam concrete with 70% content increased first and then decreased with the increase of the proportion of hybrid recycled micro powder. When the mass ratio of recycled brick powder to recycled concrete powder is 4:6, its performance indicators reach the best, with a surface dry compressive strength of 1.52 MPa, a saturated compressive strength of 1.73 MPa, a dry shrinkage of 0.40 mm, and good frost resistance (mass loss rate of 2.82%, strength loss rate of 9.88%), meeting the requirements of <i>Technical Specification for Bubble Mixed Lightweight Soil Filling Engineering</i> (CJJ/T 177-2012).</p>

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Application of Mixed Recycled Micro Powder Foam Concrete with High Content Prepared by Compound Microbial Foaming Agent in Subgrade Filling

  • Xiaomin Liu,
  • Keqi Huang,
  • Yun Zhao,
  • Simei Wang,
  • Yanan Li,
  • Jianxin Li,
  • Guanzhi Cheng,
  • Yanbin Tan,
  • Hui Rong

摘要

This study focuses on the collaborative innovation of building solid waste recycling and road- bed lightweight. Aiming at the key technical bottlenecks of high energy consumption and low utilization rate of building micro-powder of traditional foam concrete cementitious materials, this paper mixed 30%, 50% and 70% hybrid recycled micro-powder to prepare A07 density grade foam concrete, and explored the influence of hybrid recycled micro-powder content on the performance of foam concrete. A07 density grade foamed concrete with 70% mixed recycled fine powder was prepared by using composite microbial foaming agent to explore the optimal proportion of mixed recycled fine powder (recycled brick powder:recycled concrete powder is 2:8,4:6,6:4,8:2) in the field of subgrade filling, promote the recycling of mixed recycled fine powder of construction waste, and provide new filling materials with light weight, high strength and ecological benefits for subgrade engineering, which has important engineering application value for promoting the construction of ‘no waste city’. The research results show that: (1) With the increase of recycled micro powder content to 70%, the dry density of A07 grade foam concrete shows an upward trend, and the compressive strength shows a gradual downward trend. The dry density of foam concrete in BP, CP, RP (4:6), RP (6:4) groups increased by 45.5%, 32.7%, 36.9%, and 42.3% respectively compared with the control group, and the compressive strength decreased by 70%, 66%, 55%, and 64% respectively; (2) The performance of hybrid recycled micro powder foam concrete with 70% content increased first and then decreased with the increase of the proportion of hybrid recycled micro powder. When the mass ratio of recycled brick powder to recycled concrete powder is 4:6, its performance indicators reach the best, with a surface dry compressive strength of 1.52 MPa, a saturated compressive strength of 1.73 MPa, a dry shrinkage of 0.40 mm, and good frost resistance (mass loss rate of 2.82%, strength loss rate of 9.88%), meeting the requirements of Technical Specification for Bubble Mixed Lightweight Soil Filling Engineering (CJJ/T 177-2012).