Effect of freeze-thaw cycles on mechanical and porosity properties of recycled construction waste mixtures

Li, Zhe; Liu, Lulu; Yan, Shihao; Zhang, Mengke; Xia, Jingjing; Xie, Yongli

doi:10.1016/j.conbuildmat.2019.03.184

Cited by 51 publications

(14 citation statements)

References 38 publications

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“…The experimental results are in line with the results of our research on the microscopic aspect [41,42]. Based on the CT scan, we found that when the content of concrete slag is high, the interior of the filler is porous, and as the content of brick slag increases, the porosity decreases, that is, the mixture changes from a porous structure to a dense structure.…”

Section: Discussionsupporting

confidence: 88%

“…The concrete has high strength and hardly breaks under the same load, the concrete slag acts as the skeleton in the mixture. Furthermore, Li et al used a CT scan to observe the internal microstructure of the mixture [41,42], the image scanned by CT is a grayscale image, and the black parts indicate the pores of the sample, as shown in Figure 8. For the recycled aggregate used in this paper, the concrete slag has a high strength and acts as a skeleton in the mixture, while the brick slag and the mortar slag are easily broken, and the broken parts fill the gap between the concrete skeletons.…”

Section: Analysis Of Total Strainmentioning

confidence: 99%

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Investigation into Creep Characteristics and Model of Recycled Construction and Demolition Waste Used in Embankment Filler

Yan

Liu

et al. 2020

Sustainability

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The creep deformation of recycled construction and demolition waste (CDW) filler is an important factor affecting road performance. In this paper, a series of laboratory tests, including a compaction test, sieving test, California bearing ratio (CBR) test, creep test and unloading test are conducted on CDW filler. The engineering properties of different ratios of CDW mixture are systematically analyzed, the CBR value of CDW filler meets the requirements of an embankment. The creep type of CDW filler under a test load is stable creep, the results of the creep characteristics are analyzed from a microscopic point of view. The filler with a 7:2:1 ratio (brick slag: concrete: mortar) has the densest structure, which is dense and less porous, and the deformation is the smallest. Reasonable proportion control is the key to reducing embankment deformation. The improved Burgers model, which can better describe the creep characteristics of CDW filler, and the effects of load and ratio on the creep parameters are analyzed using the equivalent creep compliance. This study is of great significance for the promotion of CDW and meets the requirements of sustainable development.Sustainability 2020, 12, 1924 2 of 22 for the adverse effects of recycled aggregates [12][13][14]. When recycled aggregate is used to produce recycled asphalt, Subhy et al. [15] and Menegusso et al. [16] have studied the effects of its content and treatment method on fatigue performance. In addition, recycled aggregates are used for roadbed fillers, Javier et al. [17] found that the bearing capacity of the recycled aggregates increased with time in the structural layer, which is inconsistent with the trend of natural aggregates. Vegas et al. [18] and Yin et al. [19] studied the properties of recycled concrete applied to an embankment and introduced its permanent deformation characteristics.The application of CDW materials to embankments has great economic and environmental benefits, but the composition of recycled CDW material is complex, and its settlement after construction is difficult to predict and control, therefore, a study into its creep characteristics and mechanisms is urgently needed. The CDW mixture belongs to coarse-grained materials and the creep deformation of coarse-grained materials can be divided into stable creep and unstable creep types, according to the magnitude of stress [20,21]. The rheological curve of coarse-grained materials can be divided into three stages: linear, decaying rheology, and stability [22]. With the increase in dam height, the particle breakage of the rockfill in the rock dam increased significantly, and the particle breakage directly changed the rockfill structure [23,24]. From their triaxial creep shear test, Jiang et al. concluded that particle motion, rotation, and damage are the main causes of coarse-grained material deformation [25]. In addition to the time-dependent strain under a constant load, changes in the external environment tend to have a large effect on creep deformation, especially as immersion i...

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Section: Discussionsupporting

confidence: 88%

Section: Analysis Of Total Strainmentioning

confidence: 99%

Investigation into Creep Characteristics and Model of Recycled Construction and Demolition Waste Used in Embankment Filler

Yan

Liu

et al. 2020

Sustainability

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“…This feature can justify the improved resistance to freeze-thaw cycles, and thus, durability of H Sila/Sil and H Sil treatments compared to H NST . Furthermore, the difference in the moisture transport properties of treated limestone and mortar can be attributed also to the higher roughness of the mortar, compared to flatter surface of the limestone, which accounts for better adhesion of both fissured and crack free SiO 2 -TiO 2 films to the substrate [37].…”

Section: Discussionmentioning

confidence: 99%

“…After accelerated aging tests, untreated specimens show a significant reduction of the capillary water absorption (around 44%), which can be attributed to the modification (destruction) of capillary pores (typically observed in altered and decayed materials) [36]. In fact, a significant increase of porosity is observed mostly between 5 to 10 freeze-thaw cycles [37]. Thus, artificial aging induces the generation of new pores and the expansion of existing pores in the specimens.…”

Section: Capillary Water Absorption and Water Absorption With Karstenmentioning

confidence: 99%

Effect of Hygrothermal Aging on Hydrophobic Treatments Applied to Building Exterior Claddings

et al. 2020

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Hydrophobic materials are among the most commonly used coatings for building exterior cladding. In fact, these products are easily applied to an existing surface, significantly reduce water absorption and have a minimal impact on the aesthetic properties. On the other hand, although these products have a proven effectiveness, their long-term durability to weathering has not yet been systematically studied and completely understood. For these reasons, this study aims to correlate the effect of artificial aging on the moisture transport properties of hydrophobic treatments when applied on building exterior claddings. Three hydrophobic products (an SiO 2 -TiO 2 nanostructured dispersion; a silane/oligomeric siloxane; and a siloxane) were applied on samples of limestone and of a cement-based mortar. The moisture transport properties (water absorption, drying, water vapor permeability) of untreated and treated specimens were characterized. Furthermore, the long-term durability of the specimens was evaluated by artificial aging, that is, hygrothermal cycles (freeze-thaw and hot-cold). All treatments have significant hydrophobic effectiveness and improve the long term-durability of the treated specimens. However, the results showed that the three hydrophobic products have different effectiveness and durability, with the SiO 2 -TiO 2 nanostructured dispersion being the most durable treatment on limestone, and the siloxane the most suitable for cementitious mortar.

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“…Recycled aggregates are (Figure 10). It can be clearly seen that as the load increases, the percent finer of particles smaller than 2 mm is significantly increased, that is, for construction waste filler, the breakage and compaction of particles are the main reasons for long-term deformation [39,40]. Table 10 lists the C c and C u of different loads, and they are between the middle and lower layers after compaction.…”

Section: Analysis Of Creep Testmentioning

confidence: 99%

Long‐Term Deformation Analysis of Recycled Construction Waste Subgrade Filler

Yan

Liu

et al. 2019

Advances in Civil Engineering

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The application of construction waste to subgrade has important economic and environmental significance. In order to study the long-term deformation characteristics of recycled construction waste filler, a series of laboratory tests and field measurement have been carried out. Through compaction, sieving, and California bearing ratio (CBR) tests, the gradation and CBR value of recycled construction waste filler meet the requirements of expressway subgrade. Long-term deformation tests include laboratory creep tests and field settlement measurement. The creep tests were carried out for about 500 days by a self-made consolidation creep instrument, the creep type of recycled construction waste filler under the test load is stable creep, as the load increases, not only the creep deformation increases but also the time to reach creep stability is longer, and the breakage and compaction of particles are the main reasons for long-term deformation. Through measurement and analysis, it is found that the settlement stability of the construction waste subgrade takes a long time; after the operation of road, the settlement of the subgrade has grown rapidly. Furthermore, the Burgers model can be used to predict the deformation of creep tests, and the maximum settlement of construction waste subgrade can be predicted. The research can provide reference for the application of recycled construction waste filler, and it is conducive to the promotion of construction waste subgrade.

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Effect of freeze-thaw cycles on mechanical and porosity properties of recycled construction waste mixtures

Cited by 51 publications

References 38 publications

Investigation into Creep Characteristics and Model of Recycled Construction and Demolition Waste Used in Embankment Filler

Investigation into Creep Characteristics and Model of Recycled Construction and Demolition Waste Used in Embankment Filler

Effect of Hygrothermal Aging on Hydrophobic Treatments Applied to Building Exterior Claddings

Long‐Term Deformation Analysis of Recycled Construction Waste Subgrade Filler

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