Experimental Study on Construction and Demolition Recycled Materials

Abstract

Construction and demolition recycled materials (C&DRM) application research has mainly focused on recycled aggregates, foundation treatments, roadbed filling, and similar topics. However, few studies have examined the application of C&DRM for the treatment of collapsible loess foundations. a new approach of using construction and demolition recycled materials (C&DRM) as filling material of compacted pile in the treatment of collapsible loess foundation is proposed, which can improve the utilization ratio of construction waste and effectively solve the problem of road material shortage. a performance field test and a pile treatment compaction pile test, were developed and tested to assess the use of C&DRM lime-soil compaction piles for collapsible loess foundation treatment, from which the feasibility of treating collapsible loess foundations using C&DRM was determined. The C&DRM parameters and the collapsible loess foundation treatment construction parameters for the C&DRM lime-soil compaction piles were obtained. A post-construction foundation settlement monitoring test verified the engineering application.The economic benefit analysis data show that the economic benefit is significant and consistent with the environmental and social benefits. (1) The water absorption and California Bearing Ration test found that the collapsible loess foundation treatment compaction pile filling material needed a 0-30mm particle size, an optimum water content of 12%, and 72:28 proportion of C&DRM+lime-soil materials. (2) In the pile-forming test, Six performance parameters; collapsibility coefficient, pile compactness, maximum dry density, static penetration, bearing capacity, and immersion load were compared. The results showed that the effect of the C&DRM+lime-soil materials (72:28) on a collapsible loess foundation was better, the best distance to diameter ratio was 2.25 and the bearing capacity of the foundation was up to 320 kPa, which met the design foundation bearing capacity (>220 kPa) requirements.(3) In the post-construction settlement monitoring,the maximum settlement was 15.6243mm predicted by hyperbolic method., which indicated that the collapsible loess foundation treatment was effective.

Keywords: Application test; C&DRM; Collapsible loess foundation; Economic analysis

JEL Classification: L74