Analysis of Compressive Strength and Failure Mechanism Based on Series Homogenization Model for Recycled Concrete

2021 ◽  
Vol 10 (02) ◽  
pp. 153-161
Author(s):  
Safwan Fouad Al-Sayed
Keyword(s):  
Compressive Strength ◽  
Failure Mechanism ◽  
Recycled Concrete ◽  
Homogenization Model

scholarly journals Analysis of Tensile Strength and Failure Mechanism Based on Parallel Homogenization Model for Recycled Concrete

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 145
Author(s):  
Yijiang Peng ◽  
Semaoui Zakaria ◽  
Yucheng Sun ◽  
Ying Chen ◽  
Lijuan Zhang
Keyword(s):  
Tensile Strength ◽  
Failure Mechanism ◽  
Strain Softening ◽  
Recycled Concrete ◽  
Damage Analysis ◽  
Softening Curve ◽  
Force Element ◽  
Homogenization Model ◽  
Concrete Materials ◽  
Element Method

In this paper, a parallel homogenization model for recycled concrete was proposed. A new type of finite element method, the base force element method, based on the complementary energy principle and the parallel homogenization model, is used to conduct meso-level damage research on recycled concrete. The stress–strain softening curve and failure mechanism of the recycled concrete under uniaxial compression load are analyzed using the nonlinear damage analysis program of the base force element method based on the parallel homogenization model. The tensile strength and destructive mechanisms of recycled concrete materials are studied using this parallel homogenization model. The calculation results are compared with the results of the experiments and meso-level random aggregate model analysis methods. The research results show that this parallel homogenization analysis method can be used to analyze the nonlinear damage analysis of recycled concrete materials. The tensile strength, stress–strain softening curve, and crack propagation process of recycled concrete materials can be obtained using the present method.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

Ultrasonic Test on Recycled Concrete: Relationship among Ultrasonic Waves Velocity, Compressive Strength and Elastic Modulus

2014 ◽  
Vol 894 ◽  
pp. 45-49 ◽  
Author(s):  
Luisa Pani ◽  
Lorena Francesconi
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Ultrasonic Wave ◽  
Ultrasonic Test ◽  
Ultrasonic Waves ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Experimental Program ◽  
Static Modulus ◽  
Cylindrical Samples

In this paper an experimental program has been carried out in order to compare compressive strength fcand elastic static modulus Ecof recycled concrete with ultrasonic waves velocity Vp, to establish the possibility of employing nondestructive ultrasonic tests to qualify recycled concrete. 9 mix of concrete with different substitution percentage of recycled aggregates instead of natural ones and 27 cylindrical samples have been made. At first ultrasonic tests have been carried out on cylindrical samples, later elastic static modulus Ecand compressive strength fchave been experimentally evaluated. The dynamic elastic modulus Edhas been determined in function of ultrasonic wave velocity Vp; furthermore the correlations among Ed, Ec, fce Vphave been determined. It has been demonstrated that ultrasonic tests are suitable for evaluating different deformative and resisting concrete performances even when variations are small.

Study on the Mechanical Properties and Frost Resistance of Recycled Concrete Prepared by Village Construction Wastes

2011 ◽  
Vol 418-420 ◽  
pp. 406-410
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Dan Dan Hong ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Cement Mortar ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Concrete Mechanical Properties ◽  
Better Than

Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

Effect of nano metakaolin on compressive strength of recycled concrete

2020 ◽  
Vol 256 ◽  
pp. 119393 ◽  
Author(s):  
Jun Xie ◽  
Heng Zhang ◽  
Long Duan ◽  
Yongzhu Yang ◽  
Jie Yan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete

scholarly journals Experimental Research on the Mechanical Characteristics and the Failure Mechanism of Coal-Rock Composite under Uniaxial Load

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ke Yang ◽  
Zhen Wei ◽  
Xiaolou Chi ◽  
Yonggang Zhang ◽  
Litong Dou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Crack Propagation ◽  
Failure Mechanism ◽  
Poisson’S Ratio ◽  
Mechanical Characteristics ◽  
Poisson's Ratio ◽  
Energy Value ◽  
Coal Rock

Due to the influence of the component structure and combination modes, the mechanical characteristics and failure modes of the coal-rock composite show different characteristics from the monomer. In order to explore the effect of different coal-rock ratios on the deformation and the failure law of the combined sample, the RMT rock mechanics test system and acoustic emission real-time monitoring system are adopted to carry out uniaxial compression tests on coal, sandstone, and three kinds of combined samples. The evolution rules of the mechanical parameters of the combined samples, such as the uniaxial compressive strength, elastic modulus, and Poisson’s ratio, are obtained. The expansion and failure deformation characteristics of the combined sample are analyzed. Furthermore, the evolution laws of the fractal and acoustic emission signals are combined to reveal the crack propagation and failure mechanism of the combined samples. The results show that the compressive strength and elastic modulus of the combined sample increase with the decrease of the coal-rock ratios, and Poisson’s ratio decreases with the decrease of the coal-rock ratios. The strain softening weakens at the postpeak stage, which shows an apparent brittle failure. The combined sample of coal and sandstone has different degrees of damages under load. The coal is first damaged with a high degree of breakage, with obvious tensile failure. The acoustic emission energy value presents different stage characteristics with increasing load. Crackling sound occurs in the destroy section before the sample reaches the peak, along with small coal block ejection and the partial destruction. The energy value fluctuates violently, with the appearance of several peaks. At the postpeak stage, the coal samples expand rapidly with a loud crackling sound in the destroy section, and the energy value increases dramatically. The crack propagation induces the damage in the sandstone; when the energy reaches the limit value, the instantaneous release of elastic energy leads to the overall structural instability.

scholarly journals Acidic solution effects on no-fines concrete produced by using recycled concrete as coarse aggregate

2018 ◽  
Vol 162 ◽  
pp. 02002
Author(s):  
Ikbal Gorgis ◽  
Whab Faleh Abd ◽  
Shaker Al-Mishhadani
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Maximum Size ◽  
Recycled Concrete ◽  
Type I ◽  
Coarse Aggregates ◽  
Crushed Concrete ◽  
Compaction Factor ◽  
Single Size ◽  
Better Than

This paper investigates durability of no fine concrete containing demolished concrete as coarse aggregate after crushing to different sizes. Different no fine concrete mixes were considered using Portland cement type I with two types of coarse aggregates, crushed demolished concrete and crushed natural gravel were used with two ratios by weight (1:5 and 1:7) C/Agg. Graded aggregate and single size were used with a maximum size of 20 mm. W /C ratio was kept as 0.4 for all mixes and super-plasticizer was required to keep the same flow and compaction factor value for all mixes. Cube specimens with 150mm were cured and divided to two parts, the first part was exposed to 60 cycles of freezing- thawing; the second part of the sample was immersed in Nitric Acids solution with pH of 3.5 for (7, 28, 90 and 180 days) and then tested for compressive strength. The results indicated that it is possible to produce homogenous and workable mixes by using demolished crushed concrete as coarse aggregate. The compressive strength after cycles of freezing- thawing and immersing in Nitric acid (HNO3) at (7, 28, 90 and 180) days was decreased for samples made with crushed demolished concrete. Also it is found that the performance of concrete mixes containing graded coarse aggregate and 1:5 cement/aggregate ratios was better than other mixes.

Mechanical Performances of Green Engineered Cementitious Composites Incorporating Various Types of Sand

2019 ◽  
Vol 821 ◽  
pp. 512-517
Author(s):  
Siong Wee Lee ◽  
Chai Lian Oh ◽  
Mohd Raizamzamani Md Zain ◽  
Norrul Azmi Yahya ◽  
Azerai Ali Rahman
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Cementitious Composites ◽  
Flexural Stress ◽  
Engineered Cementitious Composites ◽  
River Sand ◽  
Granulated Blast Furnace Slag ◽  
In Series ◽  
Mechanical Performances ◽  
Flexural Tests

This paper evaluates the mechanical performances of green engineered cementitious composites (ECC) by means of compressive strength and flexural behaviour. Green ECC made of cement, ground granulated blast-furnace slag (GGBS), river sand or recycled concrete fine (RCF), polypropylene (PP) fiber, water and superplasticizer (SP) was employed in this study. Compression test result implies that green ECC incorporating either sieved river sand or sieved RCF (below 600 μm) in series G60 and G70 exhibited greater compressive strength compared with green ECC with unsieved river sand. In series G80, compressive strength of green ECC was not affected by RCF content. Flexural stress-mid deflection curves demonstrated that all green ECC specimens performed more ductile compared to normal concrete as they undergone large deformation capacity after the first cracking strength. Both compression and flexural tests suggested that mixture G80SRCF0.4 containing large amount of sieved RCF and least amount of cement is the best green ECC mixture in this study.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete with Different Replacement Ratios

2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
Author(s):  
Hai Yong Cai ◽  
Min Zhang ◽  
Ling Bo Dang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Failure Mode ◽  
Failure Process ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Replacement Ratio ◽  
Aggregate Concrete

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.

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