Epoxy (EP) is commonly known as a structural adhesive for bonding with building materials, with a broad application prospect. However, its wide applications are constrained by its high contraction ratio, poor ductilit...
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Epoxy (EP) is commonly known as a structural adhesive for bonding with building materials, with a broad application prospect. However, its wide applications are constrained by its high contraction ratio, poor ductility, short curing time and high cost. With normal-temperature pouring type structural adhesive for buildings as object, this paper studies the impact of silica flour on the basic performance of epoxy through physical and mechanical tests by adding the silica flour having a particle size of 500 meshes. Research results show that, as long as no basic mechanical properties are impacted, the adding of proper amount of silica flour can extend the curing time of epoxy to some extent and provide sufficient time for construction;reduce the contraction ratio of epoxy in volume and the danger caused by internal stress;obviously limit the bubbles generated in epoxy curing and eliminate potential safety hazards;as well as save costs to a certain extent. The optimum percentage of silica flour was also obtained in the study.
The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobising agents based on organosilicon compounds for surface protection on the lightweight mortars with pumice aggregate. T...
The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobising agents based on organosilicon compounds for surface protection on the lightweight mortars with pumice aggregate. The work discusses the issues related to absorptivity and wettability of the surface layer of mortars. The experimental part pertains to the physical and mechanical properties of pumice-modified mortars and the influence of hydrophobising agents on the contact angle and surface free energy depending on the humidity of the substrate. The contact angle of lightweight mortars (θw) was determined in the function of moisture using a single measurement liquid. This provided a basis for calculating the surface free energy with Neumann method, characterizing the wettability and adhesion of mortars. The structure of polisiloxane film was presented by means of scanning electron microscopy. The studies enabled to determine the hydrophobisation efficiency of heat-insulating mortars with pumice aggregate at various degrees of humidity of the substrate: 0%; 1%; 3%; 6%. The obtained results confirmed the possibility of producing pumice-modified mortars along with proper surface protection against moisture. The acceptable level of moisture content at which the hydrophobisation is still effective was defined as well.
Modeling as-is site condition and tracking the three-dimensional (3D) location of mobile assets (e.g., worker, equipment, material) are essential for various construction applications such as progress monitoring, qual...
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Modeling as-is site condition and tracking the three-dimensional (3D) location of mobile assets (e.g., worker, equipment, material) are essential for various construction applications such as progress monitoring, quality control and safety management. Many efforts have been dedicated to vision-based technologies due to their merits in cost-effectiveness and light infrastructure compared to real-time location systems (RTLS). However, a major challenge of vision-based tracking is that it lacks 3D information and thus the results are sensitive to occlusion, illumination conditions and scale variation. To address this problem, this study presents a point cloud-vision hybrid approach to reconstruct and update the area of interest in 3D for scene updating and mobile asset tracking. Baseline 3D geometry information in point cloud is obtained at the start by Structure from Motion (SfM) using Unmanned Aerial Vehicle (UAV), given which mobile and static assets present in the scene are recognized and labeled. Based on 2D aerial isometric images capture by the UAV, labeled assets are automatically recognized and their locations are updated. The proposed approach was implemented in a field test and the results demonstrate that it was able to reconstruct the site and update the location of mobile assets accurately and reliably. Findings in this study indicate the proposed hybrid approach effectively augments the state-of-the-art in site modeling and asset tracking in construction.
This study investigates the durability of partially-damaged concrete with the addition of Silica Fume and Ground Granulated Blast Furnace Slag. Portland cement was replaced by 10% SF and 60% of GGBFS as a replacement ...
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This paper presents an experimental study on bending behavior of aramid and steel fiber reinforced concrete (AFRC and SFRC) members. The objective is to investigate effects of two types of aramid fiber and one type of...
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This paper presents an automatic crack inspection system for concrete tunnel lining based on image processing technique and computer vision. The system includes a video image acquisition device, an image stitching sof...
This paper presents an automatic crack inspection system for concrete tunnel lining based on image processing technique and computer vision. The system includes a video image acquisition device, an image stitching software, and a crack detection software. Firstly, the video image acquisition device uses six video cameras and three illuminators mounted on a steel framework which is capable of sliding from side to top of the inspecting vehicle to shoot the full surface of the tunnel lining. Secondly, the image stitching software based on image matching technique was developed to create layout panorama from the tunnel lining surface images, making it easier to visualize a large and detailed section of the tunnel lining. Finally, we propose a semi-automatic crack detection software relied on a combination of image processing technique and interactive genetic algorithm (iGA) to crack detection for concrete surface images of the tunnel lining. Experimental results demonstrate the effectiveness of the proposed method.
In order to study the uniaxial loading failure process of pervious concrete and the influence of water-cement ratio and loading rate on the compressive strength, we carry out indoor uniaxial compression test and estab...
In order to study the uniaxial loading failure process of pervious concrete and the influence of water-cement ratio and loading rate on the compressive strength, we carry out indoor uniaxial compression test and establish parallel bond model by discrete element program PFC2D to analysis from the angle of micro. By comparing the indoor test data with discrete element simulation results, we found that the compressive strength of pervious concrete increased with the increase of water cement ratio, and there is a difference between the state of failure and the distribution of cracks. With the increase of loading rate, the compressive strength of pervious concrete is improving, the corresponding peak point strain is reducing, the number of microscopic cracks is decreasing, and the degree of breakage is reducing.
Xiaowang Town of Xinyang City is taken as research target. Based on regional coordination,ecological coordinated development and status analysis,the development orientation of Xiaowang Town is studied and perfected de...
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Xiaowang Town of Xinyang City is taken as research target. Based on regional coordination,ecological coordinated development and status analysis,the development orientation of Xiaowang Town is studied and perfected deeply from space structure layout,road traffic planning,ecological landscape construction and residential space reconstruction. It is devoted to creating a suburban recreational resort and ecological livable new town with prominent industry function,distinctive style and feature,urban-rural integration,and hopes to provide certain reference for ecological construction of related towns at home and abroad.
This research focuses on identifying waiting time in design process. This comprised the application of value stream mapping to identify existing flows and design waiting times. From this diagnosis, it was possible to ...
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This research focuses on identifying waiting time in design process. This comprised the application of value stream mapping to identify existing flows and design waiting times. From this diagnosis, it was possible to propose recommendations reducing identified waste of time. This study demonstrates the viability of using the value stream mapping and to improve architectural designs process.
作者：
Wernicke, BrianLidelöw, HelenaDept. of Civil
Environmental and Natural Resources Engineering Division of Industrialized and Sustainable Construction Luleå Univ. of Technology Luleå97187 Sweden
construction companies traditionally try to optimize their resource efficiency to minimize costs. Today's demand for value stream optimization along the whole supply chain cannot be resolved by that approach. To b...
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