scholarly journals Using Eco-Friendly Recycled Powder from CDW to Prepare Strain Hardening Cementitious Composites (SHCC) and Properties Determination

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1143 ◽  
Author(s):  
Wan Wang ◽  
Huixia Wu ◽  
Zhiming Ma ◽  
Ruixue Wu
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Ultimate Load ◽  
Cementitious Materials ◽  
Construction And Demolition Waste ◽  
Cementitious Composites ◽  
Demolition Waste ◽  
Supplementary Cementitious Material ◽  
Pva Fiber ◽  
Ultimate Displacement

Using eco-friendly recycled brick powder (RBP) derived from waste brick to prepare strain hardening cementitious composites (SHCC) provides a new way of recycling the construction and demolition waste (CDW), and the dosage of cement in SHCC can be decreased. This paper investigated the micro-properties and mechanical properties of SHCC containing RBP by a series of experiments. The results showed that RBP had typical characteristics of supplementary cementitious material (SCM). The addition of RBP increased the SiO2 content and decreased the hydration products in cementitious materials; in this case, the mechanical properties of mortar decreased with increasing RBP replacements, and a linear relationship was observed between them. It was noticed that the adverse effect of RBP on the mechanical properties decreased with increasing PVA fiber content in mortar. For SHCC containing various RBP replacements, the ultimate load increased, and the ultimate displacement decreased with increasing curing days. When using RBP to replace cement by weight, the ultimate displacement increased with the addition of RBP. Meanwhile, there was no significant reduction in the ultimate load of SHCC. When using RBP to replace fly ash (FA) by weight, the incorporation of RBP decreased the ultimate displacement of SHCC, whereas the ultimate load was improved. For example, the ultimate load and displacement of SHCC with 54%RBP were 17.6% higher and 16.4% lower, respectively, than those of SHCC with 54% FA.

scholarly journals Some Properties of Concrete Containing Waste Brick As Partial Replacement Of Coarse Aggregate And Addition Of Nano Brick Powder

2022 ◽  
Vol 961 (1) ◽  
pp. 012093
Author(s):  
Duaa Jabbar Abdullah ◽  
Zena K Abbas ◽  
Suhair Kadhem Abed
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Coarse Aggregate ◽  
Cementitious Materials ◽  
Construction And Demolition Waste ◽  
Nano Particles ◽  
Partial Replacement ◽  
Slight Improvement ◽  
Demolition Waste ◽  
Brick Powder

Abstract The accumulation of construction and demolition waste is one of the major problems in modern construction. Hence, this research investigates the use of waste brick in concrete. Seven different concrete mixes were investigated in this study: a control concrete mix, three mixes with volumetric replacement (10, 20, and 30)% of natural aggregate with brick aggregate, and two mixes with the addition of nano brick powder at a percentage level of 5– 10% by weight of cementitious materials. And the last one was mixed with 10% nano brick and 10% coarse brick aggregate. The experimental results for the additive of nano brick powder showed an enhancement in mechanical properties (compressive, flexural, and tensile strength) compared to the control mix for all ages, while the mixes with 10% coarse brick replacement also showed a slight improvement in the mechanical properties up to 5.33%, 2.79%, and 2.38% for compressive, splitting tensile, and flexural strength, respectively, at 28 days. The nano particles modified the mechanical properties of the CBA concrete when mixed with 10% nano brick and 10% coarse brick aggregate, up to 11.54%, 8.56%, and 3.3% for compressive, flexural, and tensile strength, respectively, at 150 days.

scholarly journals An Overview on the Rheology, Mechanical Properties, Durability, 3D Printing, and Microstructural Performance of Nanomaterials in Cementitious Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2950
Author(s):  
Hongwei Song ◽  
Xinle Li
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Research Area ◽  
Cementitious Composites ◽  
Split Tensile Strength ◽  
Contour Crafting ◽  
Wide Range ◽  
Active Research

The most active research area is nanotechnology in cementitious composites, which has a wide range of applications and has achieved popularity over the last three decades. Nanoparticles (NPs) have emerged as possible materials to be used in the field of civil engineering. Previous research has concentrated on evaluating the effect of different NPs in cementitious materials to alter material characteristics. In order to provide a broad understanding of how nanomaterials (NMs) can be used, this paper critically evaluates previous research on the influence of rheology, mechanical properties, durability, 3D printing, and microstructural performance on cementitious materials. The flow properties of fresh cementitious composites can be measured using rheology and slump. Mechanical properties such as compressive, flexural, and split tensile strength reveal hardened properties. The necessary tests for determining a NM’s durability in concrete are shrinkage, pore structure and porosity, and permeability. The advent of modern 3D printing technologies is suitable for structural printing, such as contour crafting and binder jetting. Three-dimensional (3D) printing has opened up new avenues for the building and construction industry to become more digital. Regardless of the material science, a range of problems must be tackled, including developing smart cementitious composites suitable for 3D structural printing. According to the scanning electron microscopy results, the addition of NMs to cementitious materials results in a denser and improved microstructure with more hydration products. This paper provides valuable information and details about the rheology, mechanical properties, durability, 3D printing, and microstructural performance of cementitious materials with NMs and encourages further research.

scholarly journals Engineering and Manufacturing Technology of Green Epoxy Resin Coatings Modified with Recycled Fine Aggregates

2021 ◽  
Author(s):  
Kamil Krzywiński ◽  
Łukasz Sadowski ◽  
Damian Stefaniuk ◽  
Aleksei Obrosov ◽  
Sabine Weiß
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Construction And Demolition Waste ◽  
Fine Aggregate ◽  
Micro Computed Tomography ◽  
Demolition Waste ◽  
Replacement Ratio ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Computed Tomography Scanning

AbstractNowadays, the recycled fine aggregate sourced from construction and demolition waste is not frequently used in manufacturing of epoxy resin coatings. Therefore, the main novelty of the article is to prepare green epoxy resin coatings modified with recycled fine aggregate in a replacement ratio of natural fine aggregate ranged from 20 to 100%. The microstructural properties of the aggregates and epoxy resin were analyzed using micro-computed tomography, scanning electron microscopy and nanoindentation. The macroscopic mechanical properties were examined using pull-off strength tests. The highest improvement of the mechanical properties was observed for epoxy resin coatings modified with 20% of natural fine aggregate and 80% of recycled fine aggregate. It has been found that even 100% of natural fine aggregate can be successfully replaced using the recycled fine aggregate with consequent improvement of the pull-off strength of analyzed epoxy resin coatings. In order to confirm the assumptions resulting from the conducted research, an original analytical and numerical failure model proved the superior behavior of modified coating was developed.

scholarly journals Effect of different PVA and steel fiber length and content on mechanical properties of CaCO3 whisker reinforced cementitious composites

2019 ◽  
Vol 69 (336) ◽  
pp. 200 ◽  
Author(s):  
M. Cao ◽  
C. Xie ◽  
L. Li ◽  
M. Khan
Keyword(s):  
Mechanical Properties ◽  
Crack Resistance ◽  
Fiber Length ◽  
Large Deflection ◽  
Steel Fiber ◽  
Flexural Behavior ◽  
Cementitious Composites ◽  
Hybrid Fiber ◽  
Pva Fiber ◽  
Fiber Reinforced Cementitious Composites

In this paper, calcium carbonate (CaCO3) whisker as a fiber reinforcement is mixed with steel and PVA fiber to form a multiscale hybrid fiber reinforced cementitious composites (MHFRCC). ASTM standard and post-crack strength techniques are performed to evaluate the mechanical properties of MHFRCC. The 1.25 % long steel fiber, 0.55 % short PVA fiber and 2.0 % CaCO3 whisker specimens showed the best flexural behavior before L/600 deflection. However, 1.5 % long steel fiber, 0.4 % long PVA fiber and 1.0 % CaCO3 whisker specimens presented better crack resistance after L/600 deflection. It is revealed that flexural parameters increase as comprehensive reinforcing index increase. The result showed that the CaCO3 whisker and short PVA fiber provided crack resistance effect at micro-scale and mainly play a dominate role in inhibiting micro-cracking. However, long steel fiber and long PVA fiber showed a better bridging effect of macro cracks at a large deflection.

Study on the Preparation of Green and Environmentally Friendly High Toughness Cementitous Composites with Large Amount of Fly Ash

2020 ◽  
Vol 996 ◽  
pp. 97-103
Author(s):  
Xiang Rong Cai ◽  
Bai Quan Fu ◽  
Zhi Gang Liu
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Strain Hardening ◽  
Cementitious Composites ◽  
Special Focus ◽  
Type I ◽  
Flexural Performance ◽  
High Toughness ◽  
Four Point Bending ◽  
Pva Fiber

In order to reduce the environmental burden and the energy consumption of PVA fiber reinforced high toughness cementitious composites, special focus is placed on the influence of fly ash type and content and curing type on the flexural performance of high toughness cementitious composites through four-point bending tests. The high toughness cementitious composites without fly ash have been used in the program for comparison purpose. The tests results show that, compared with the basic high toughness cementitious composites, the flexural strength decreases and the deflection increases with the s/b increasing when the fly ash is added. The increase in fly ash content results in an improvement of strain hardening property and increases in both flexural strength and deflection, which show that fly ash is benefit to the pseudo strain hardening performance. However the effects of fly ash type and curing type are not obvious on the load but obvious on the deflection. The deflection of high toughness cementitious composites with type I fly ash or water curing is higher than that of type II or standard curing. It is demonstrated that all the high toughness cementitious composites studied in this paper exhibit strain-hardening and multiple cracking through adding fly ash.

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