Performance of Green Concrete and Inorganic Coating Materials

Green concrete (GC) was developed for realizing sustainable development, recycling waste materials, and reducing environmental pollution. For the practical use of GC, various harmful materials must blocked from entering its cracks and pores; and its strength and durability must be improved. The use of an inorganic coating material (ICM) for GC effectively prevents the intrusion of harmful materials and repairs the concrete. ICMs can reduce the permeability and increase the durability of concrete. This study investigated GC, construction waste, and ICMs and used recycled sand and gravel as well as construction waste as substitutes for cement. The results indicate that the coarse aggregate substitution, water-binder ratio, and recycled fine aggregate substitution must be controlled suitably in GC. Furthermore, the coating layer, fine aggregate substitution, and aging of the ICM mut be controlled suitably. GC with an ICM showed poorer performance than conventional concrete, mainly because of the high porosity. Nonetheless, the ICM somewhate reduces the porosity and resists the penetration of chloride ions, thereby promoting concrete quality.

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Bond Behavior Between Recycled Concrete Containing CDW and Different Types of Steel Bars

Journal of Architectural Environment & Structural Engineering Research ◽

10.30564/jaeser.v4i2.2810 ◽

2021 ◽

Vol 4 (2) ◽

Author(s):

Carine N. S. Reis ◽

Paulo R. L. Lima ◽

Mônica B. Leite

Keyword(s):

Recycled Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Fine Aggregate ◽

Demolition Waste ◽

Conventional Concrete ◽

Recycled Fine Aggregate ◽

Steel Bar ◽

Internal Forces ◽

Steel Rebars

The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete, which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements. The modification of the concrete composition, with the introduction of recycled aggregate from construction and demolition waste (CDW), affects the steel-concrete interface and can modify the bonding stress, which is also influenced by the type and diameter of the bar used. In this work, the influence of the recycled fine aggregate (RFA) and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test. Conventional concrete and recycled concrete, with RFA replacement level of 25%, were produced. Two types of steel rebars (i.e.,plain and deformed) with diameters of 10.0 and 16.0mm were considered in this paper. The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate, but this trend is influenced by the diameter of the bar used. The use of ribbed bars modifies the stress bon-slip behavior, with an increase in the average bond strength, which is also observed with the reduction of the diameter of the bar.

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La segunda vida de los residuos de construcción. Propuesta para reutilizar como agregado árido reciclado y residuos de material aislante = The second life of construction waste. Proposal to reuse recycled fine aggregate and residues of insulating materials

Anales de Edificación ◽

10.20868/ade.2019.4039 ◽

2019 ◽

Vol 5 (2) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Katarzyna Kalinowska-Wichrowska ◽

Carolina Piña Ramírez ◽

Alejandra Vidales Barriguete

Keyword(s):

Second Life ◽

Fine Aggregate ◽

Insulating Materials ◽

Construction Waste ◽

Recycled Fine Aggregate

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Experimental Study on Basic Behavior of Recycled Fine Aggregate Mortar

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.168-170.1680 ◽

2010 ◽

Vol 168-170 ◽

pp. 1680-1685 ◽

Cited By ~ 1

Author(s):

Zong Ping Chen ◽

Ni Wang ◽

Shi Qian Zhang ◽

Shu Fang Zheng

Keyword(s):

Water Absorption ◽

Absorption Rate ◽

Mechanical Performance ◽

Cement Mortar ◽

Fine Aggregate ◽

High Porosity ◽

Replacement Rate ◽

Water Absorption Rate ◽

Mortar Strength ◽

Recycled Fine Aggregate

In order to study the mechanical behavior of recycled fine aggregate mortar, 11 kinds of different recycled fine aggregate replacement rate (ranged from 0% to 100%, level differential 10%) of cement mortar test specimens are designed. The failure pattern and the mechanical performance indexes of the cement mortar under different recycled fine aggregate replacement rate are gained by test. And the different physical indexes of natural fine aggregate and recycled fine aggregate are measured in detail. The experiment findings indicate that because the water absorption rate of the mortar with high porosity is higher, and there are mass microcracks in recycled fine aggregate interior due to damage accumulation, the lower apparent density, the higher water absorption rate and the quicker water absorption speed of recycled fine aggregate are caused. So the fluidity of recycled fine aggregate mortar is fine, but the water retention is bad, the compressive strength is lower than the natural fine aggregate mortar about 50%. But the replacement rate has little effect on the mortar strength.

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Properties of Rapid Hardening Controlled Low Strength Material Made of Recycled Fine Aggregate from Urban Red Brick Construction Waste

World Journal of Engineering and Technology ◽

10.4236/wjet.2017.52015 ◽

2017 ◽

Vol 05 (02) ◽

pp. 188-197 ◽

Cited By ~ 1

Author(s):

Jin Ran ◽

Jinxi Zhang

Keyword(s):

Fine Aggregate ◽

Construction Waste ◽

Rapid Hardening ◽

Recycled Fine Aggregate ◽

Strength Material ◽

Low Strength ◽

Controlled Low Strength Material

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Reutilization of RFA of Construction Waste in Cement Mortar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.468.57 ◽

2013 ◽

Vol 468 ◽

pp. 57-60

Author(s):

Fu Xing Wang ◽

Guo Zhong Li ◽

Juan Chen

Keyword(s):

Grain Size ◽

Compressive Strength ◽

Flexural Strength ◽

Cement Mortar ◽

Mineral Admixture ◽

Fine Aggregate ◽

Hydration Products ◽

Construction Waste ◽

Recycled Fine Aggregate ◽

Micro Morphology

The effect of some factors(dosage and grain size of recycled fine aggregate of construction waste, content of mineral admixture) on the properties of cement mortar was studied. The results indicated that when recycled fine aggregate particles gradation was areaⅡ, replacement percentage (sand) was 60%,dosage of mineral admixture was 36%, compared with blank sample, the 28d flexural strength and the compressive strength of cement mortar samples were increased by 30.7% and 37.2%, respectively. Micro-morphology of section on cement mortar was observed by SEM. Identifying the hydration products through XRD was carried out.

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Performance Evaluation of Soft Computing for Modeling the Strength Properties of Waste Substitute Green Concrete

Sustainability ◽

10.3390/su13052867 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2867

Author(s):

Muhammad Izhar Shah ◽

Muhammad Nasir Amin ◽

Kaffayatullah Khan ◽

Muhammad Sohaib Khan Niazi ◽

Fahid Aslam ◽

...

Keyword(s):

Predictive Models ◽

Parametric Study ◽

Cross Validation ◽

Strength Properties ◽

Fine Aggregate ◽

Agricultural Industry ◽

Green Concrete ◽

Concrete Properties ◽

Water To Cement Ratio ◽

Sugarcane Bagasse Ash

The waste disposal crisis and development of various types of concrete simulated by the construction industry has encouraged further research to safely utilize the wastes and develop accurate predictive models for estimation of concrete properties. In the present study, sugarcane bagasse ash (SCBA), a by-product from the agricultural industry, was processed and used in the production of green concrete. An advanced variant of machine learning, i.e., multi expression programming (MEP), was then used to develop predictive models for modeling the mechanical properties of SCBA substitute concrete. The most significant parameters, i.e., water-to-cement ratio, SCBA replacement percentage, amount of cement, and quantity of coarse and fine aggregate, were used as modeling inputs. The MEP models were developed and trained by the data acquired from the literature; furthermore, the modeling outcome was validated through laboratory obtained results. The accuracy of the models was then assessed by statistical criteria. The results revealed a good approximation capacity of the trained MEP models with correlation coefficient above 0.9 and root means squared error (RMSE) value below 3.5 MPa. The results of cross-validation confirmed a generalized outcome and the resolved modeling overfitting. The parametric study has reflected the effect of inputs in the modeling process. Hence, the MEP-based modeling followed by validation with laboratory results, cross-validation, and parametric study could be an effective approach for accurate modeling of the concrete properties.

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Chloride Binding Capacity and Its Effect on the Microstructure of Mortar Made with Marine Sand

Sustainability ◽

10.3390/su13084169 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4169

Author(s):

Congtao Sun ◽

Ming Sun ◽

Tao Tao ◽

Feng Qu ◽

Gongxun Wang ◽

...

Keyword(s):

Binding Capacity ◽

Chloride Content ◽

Chloride Ions ◽

Fine Aggregate ◽

Chloride Binding ◽

River Sand ◽

Total Chloride ◽

Curing Period ◽

Marine Sand ◽

Bound Chloride

Chloride binding capacity and its effect on the microstructure of mortar made with marine sand (MS), washed MS (WMS) and river sand (RS) were investigated in this study. The chloride contents, hydration products, micromorphology and pore structures of mortars were analyzed. The results showed that there was a diffusion trend for chloride ions from the surface of fine aggregate to cement hydrated products. During the whole curing period, the free chloride content in the mortars made by MS and WMS increased firstly, then decreased and stabilized finally with time. However, the total chloride content of three types of mortar hardly changed. The bound chloride content in the mortars made by MS and WMS slightly increased with time, and the bound chloride content included the MS, the WMS and the RS arranged from high to low. C3A·CaCl2·10H2O (Friedel’s salt) was formed at the early age and existed throughout the curing period. Moreover, the volume of fine capillary pore with a size of 10–100 nm increased in the MS and WMS mortar.

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

International Journal of Precision Engineering and Manufacturing-Green Technology ◽

10.1007/s40684-021-00377-w ◽

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.

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