Lei Guo^1,2,3, Zi Guan¹, Lixia Guo^1,2,3,*, Weiping Shen¹, Zhilong Xue¹, Pingping Chen¹, Mingru Li¹

Journal of Renewable Materials, Vol.8, No.12, pp. 1711-1727, 2020, DOI:10.32604/jrm.2020.013415 - 12 November 2020

Abstract A recycled aggregate (RA) was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties. On this basis, pervious concrete (PC) mix proportions were designed. Coarse RA particles with sizes of 5–10 and 10–20 mm were selected. Concrete specimens were prepared with a water–cement ratio of 0.3, an aggregate–cement ratio of 4.5, the substitute rates of RA with 0, 25%, 50%, 75% and a single-/double-gap-graded RA mix (mass ratio of particles with sizes of 5–10 mm to particles with sizes of 10–20 mm: 1:1,… More >

Yang Ming^1,2,3, Ping Chen^1,2,3,*, Yuanhao Wang^1,2,3,*, Ling Li^1,2,3, Xuandong Chen^1,2,3, Pengliang Sun^1,2,3,4

Journal of Renewable Materials, Vol.8, No.12, pp. 1647-1655, 2020, DOI:10.32604/jrm.2020.011929 - 12 November 2020

Abstract In order to increase use ratio of steel slag solid waste, the concrete containing steel slag powder and zeolite powder as admixtures was prepared by using the orthogonal test method. The effects of water-binder ratio, sand ratio, steel slag powder content and zeolite powder on working properties, mechanical strength and chloride ion permeability of the concrete was studied. It was found that the early strength of the concrete had a decrease with the mixing of steel slag and zeolite powders, but its later strength approached to pure concrete. Moreover, the physical filling and pozzolanic activity More >

Eslam Mohammed Abdelkader^1,2,*, Osama Moselhi³, Mohamed Marzouk⁴, Tarek Zayed⁵

Intelligent Automation & Soft Computing, Vol.26, No.4, pp. 643-661, 2020, DOI:10.32604/iasc.2020.010100

Abstract Image segmentation is one of the fundamental stages in computer vision applications. Several meta-heuristics have been applied to solve the segmentation problems by extending the Otsu and entropy functions. However, no single-objective function can optimally handle the diversity of information in images besides the multimodality issues of gray-level images. This paper presents a self-adaptive multi-objective optimization-based method for the detection of crack images in reinforced concrete bridges. The proposed method combines the flexibility of information theory functions in addition to the invasive weed optimization algorithm for bi-level thresholding. The capabilities of the proposed method are More >

Zhenhua Duan, Nv Han, Amardeep Singh, Jianzhuang Xiao^*

Journal of Renewable Materials, Vol.8, No.11, pp. 1375-1390, 2020, DOI:10.32604/jrm.2020.013044 - 28 September 2020

Abstract Recycled aggregates (RA) are frequently obtained from various unknown sources, which caused variation in properties among recycled aggre- gates concrete (RAC). This paper investigated the macro and microscopic proper- ties of RAC prepared with RAs originated from different parent concretes with 90-day strength ranging from 30 MPa to 100 MPa. These parent concretes were prepared in advance and crushed to produce RA of distinct qualities. The attached mortar content can reach up to 69% in the concrete with highest strength grade. The microscopic investigation on different RAC was conducted with the X-ray Micro-Computed Tomography scanning More >

Hua Yan^1,2,3,*, Bo Song^1,3, Mansheng Wang⁴

Structural Durability & Health Monitoring, Vol.14, No.3, pp. 265-282, 2020, DOI:10.32604/sdhm.2020.06403 - 14 September 2020

Abstract Analyze and compare the basic principles of ultrasonic detection of voids in concrete, choose ZBL-U520/510 non-metallic ultrasonic detector, and use the opposite detection method to test the void size in the joints of prefabricated concrete structures. The results show that: ultrasonic method by testing the waveform, sound, and speed of sound analysis can effectively determine the position of the defect, and through the conversion formula can estimate the void size. Ultrasonic parameters are used to distinguish the internal defects of Assembly concrete. Sometimes there are different results with different parameters. It is difficult for engineers… More >

Sanghyo Lee¹, Yonghan Ahn², Ha Young Kim^{3, *}

CMC-Computers, Materials & Continua, Vol.65, No.1, pp. 1-17, 2020, DOI:10.32604/cmc.2020.011104 - 23 July 2020

Abstract In this study, we examined the efficacy of a deep convolutional neural network (DCNN) in recognizing concrete surface images and predicting the compressive strength of concrete. A digital single-lens reflex (DSLR) camera and microscope were simultaneously used to obtain concrete surface images used as the input data for the DCNN. Thereafter, training, validation, and testing of the DCNNs were performed based on the DSLR camera and microscope image data. Results of the analysis indicated that the DCNN employing DSLR image data achieved a relatively higher accuracy. The accuracy of the DSLR-derived image data was attributed… More >

Xibo Qi¹, Yijie Huang^2,3,*, Xiaowei Li¹, Zhenhua Hu¹, Jingwei Ying³, Dayong Li¹

Journal of Renewable Materials, Vol.8, No.8, pp. 915-937, 2020, DOI:10.32604/jrm.2020.010991 - 10 July 2020

Abstract The mechanical properties of modified sea water sea sand coral concrete (SWSSCC) under axial compression were experimentally studied. Two different parameters were considered in this test: types of cement and fiber. An experimental campaign was developed involving uniaxial compression tests and the use of digital image correlation (DIC) method to analyze the strain distribution and crack propagation of specimen. Test results indicated that the compressive strength and elastic modulus of SWSSCC were improved by adding stainless steel fibers (SSF), while polypropylene fibers (PF) enhanced the SWSSCC peak deformation. It was found that the elastic modulus More >

Hui Wang^1,2, Shiqin He^1,*, Xiaoqiang Yin³, Zeyang Cao¹

Structural Durability & Health Monitoring, Vol.14, No.2, pp. 95-108, 2020, DOI:10.32604/sdhm.2020.06595 - 23 June 2020

Abstract In marine environments, reinforced concrete bridge structures are subjected to cyclic loads and chloride ingress, which results in corrosion of the reinforcing bars, early deterioration, durability loss, and a considerable reduction in the fatigue strength. Owing to the complexity of the problem and the difficulty of testing, there are few studies on the fatigue performance of concrete structures under the combined action of corrosion environment and cyclic load. Therefore, a coupling test device for corrosion and cyclic load is designed and fatigue tests of reinforced concrete beams in air environments and chlorine salt corrosive environments… More >

Haikuan Wu^1,2, Changwu Liu^1,2,*, Song Shi^1,2, Kangliang Chen^1,2

Journal of Renewable Materials, Vol.8, No.7, pp. 727-738, 2020, DOI:10.32604/jrm.2020.09589 - 01 June 2020

Abstract In order to study the effect of recycled plastic particles on the physical and mechanical properties of concrete, recycled plastic concrete with 0, 3%, 5% and 7% content (by weight) was designed. The compressive strength, splitting tensile strength and the change of mass caused by water absorption during curing were measured. The results show that the strength of concrete is increased by adding recycled plastic into concrete. Among them, the compressive strength and the splitting tensile strength of concrete is the best when the plastic content is 5%. With the increase of plastic content, the… More >

Zishen Li¹, Xiangling Gao^{1, *}, Zicheng Tang²

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1105-1129, 2020, DOI:10.32604/cmes.2020.09047 - 28 May 2020

Abstract The numerical simulation for a new type of precast concrete barrier for viaducts is carried out systematically. To obtain an accurate representation of the damage state of the concrete barrier under the impact of a vehicle, a stochastic damage-plasticity model of the concrete is adopted in the finite element model. Meanwhile, a simplified mathematical model of the impact between vehicles and the concrete barrier was established and the input energy was converted to the impact load to facilitate the investigation of the safety performance of the concrete barriers. On this basis, a refined finite element More >