The effects of polymer latex, ductile fiber on the flexural strength, compressive strength, bond strength, shrinkage rate, and resistance to chloride ion attack of repair mortar were comprehensively studied. The resul...
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The effects of polymer latex, ductile fiber on the flexural strength, compressive strength, bond strength, shrinkage rate, and resistance to chloride ion attack of repair mortar were comprehensively studied. The results show that, compared with the blank mortar, the loading of polymer latex improves the flexural strength, bond strength, the impermeability, and the resistance to chloride ion attack of the mortar, and the bonding strength is increased by 75.78%. Some ductile fibers loading also enhances the flexural and compressive strength, and the toughness(the ratio of flexural to compressive strength) of mortar, respectively;the corresponding 3-day, 28-day shrinkage rate both decreases, and the 28-day shrinkage rate is reduced by 40.54%. When the polymer latex and ductile fiber are both added into the mortar together, the flexural strength, bond strength is up to 9.4 MPa and 2.52 MPa, respectively;In addition, both the shrinkage rate and the depth of chloride ion erosion are greatly reduced. SEM microstructures show that there exists dense texture and bridging fibers between hydrated cement products. The fiber-reinforced polymer mortar can be used as a type of dense and high anti-crack repair mortar, and applied onto the surface of structures, such as piers, chimneys, water towers, and so on, which will effectively delay the detachment of concrete protective layer and the corrosion of steel bars caused by environmental erosion.
Carbon nanotube(CNT) have superior mechanical & electrical properties owing to its special sp2 hybridized carbon nanostructures and electronic structure in axial direction, while it is still a challenge to fully d...
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Carbon nanotube(CNT) have superior mechanical & electrical properties owing to its special sp2 hybridized carbon nanostructures and electronic structure in axial direction, while it is still a challenge to fully disperse CNT within diversified matrix, including aqueous cement matrix, which severely limits CNT widely application in construction industry. In the present work, we employed water and sand as the dispersion agent of CNT, and prepared CNT coated sand, CNT aqueous suspension, allowing for they were both the ingredients of mortar, respectively;afterwards, they were introduced into cement mortar with a pair of pre-inserted electrodes along the length of the prism mortar with the size of 160 mm×40 mm×40 mm. Next we focused on AC impedance property under different frequency, and piezoresistive property under cyclic compressive loading of two kinds of composites. Results demonstrate that, AC impedance gradually decrease with frequency increasing, there show stable but linear relationships between AC impedance(100 kHz) and cyclic loading either CNT coated sand method or CNT aqueous suspension method, and the sensitivity is much higher than common strain gauge. This makes for the possibility the development of CNT-modified mortar as for large-scale intrinsic sensor used in infrastructure.
In order to investigate the influence of storage period and water content on dynamic mechanical properties of ready-mixed shrinkage-compensating concrete, the dynamic compression tests in 3 kinds of water contents(0.5...
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In order to investigate the influence of storage period and water content on dynamic mechanical properties of ready-mixed shrinkage-compensating concrete, the dynamic compression tests in 3 kinds of water contents(0.5% ,1.0% ,and 1.5%) and 4 kinds of storage periods(3 d,7 d,10 d,and 15 d) have been carried out by φ74 mm variable cross-section splitting Hopkinson pressure bar *** influence of water content and storage period on dynamic compressive strength and failure mode for ready-mixed shrinkage-compensating concrete have been *** result shows that at the same water content, the dynamic compressive strength decreases with the increase of storage *** the water content is 0.5 %, the strength loss rate are 4.3 %, 22.2 %, 33.9 % and 47.5 % for the storage period of 3 d, 7 d, 10 d and 15 *** the water content is 1.0 %, the strength loss rate are 11.1% 31.9 %, 41.6 % and 57.1% for the storage period of 3 d, 7 d, 10 d and 15 *** the storage period is the same, the dynamic compressive strength decreases with the increase of water *** the storage period is 7 d,the strength loss rate are 22.2% ,31.9% and 42.6% for the water content of 0.5% ,1.0% and 1.5%.When the storage period is 10 d, the strength loss rate are 33.9 %, 41.6 % and 51.5 % for the water content of 0.5 %, 1.0 % and 1.5 %,*** failure degree tends to be more serious with the increase of storage period at the same water content.
Tailings pond plays a very important role in the construction of mine engineering. At the same time, tailings pond also produces huge pollution to the environment. If dam break occurs, it will cause loss of people and...
Tailings pond plays a very important role in the construction of mine engineering. At the same time, tailings pond also produces huge pollution to the environment. If dam break occurs, it will cause loss of people and property. In this paper, a tailings pond management system based on RSCIC is studied, the monitoring content of the system is determined, the more innovative system and hardware are emphasized, the program flow chart of digital processing is put forward. Adopting scientific and effective means to manage the tailing dam automatically can not only strengthen the safety protection of the tailing dam, but also provide a certain theoretical basis for the construction of other digital tailings dam projects.
In this study, a pavement evaluation was carried out on a corridor that carried heavy truck traffic, connecting a harbor, a major high-way, an airport, and industries. The pavement of the corridor was distressed frequ...
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Worldwide, there is a clear imperativeness to reduce the consumption of non-renewable raw materials. The aim of the research is to obtain new ecological materials with applicability in the construction field, but also...
Worldwide, there is a clear imperativeness to reduce the consumption of non-renewable raw materials. The aim of the research is to obtain new ecological materials with applicability in the construction field, but also to efficiently manage these by-products by eliminating it completely and re-introducing it into the economic circuit. We envisaged the use of slag products as a material cementitious characteristics or as artificial aggregates, so that materials embedded in construction produce as little environmental impact as possible. After cooling, the blast furnace slag products was used in the new mortar mixes in two forms: in the form of a powder product milled from the granulated slag, and in the form of an aggregate made of non-granulated slag, sorted to the sized of 0/4 mm. Ground-granulated slag in the form of a powder below 63 μm was used as an addition to the cement mass, and the newly obtained artificial aggregate, sorted to 0/4 mm, was used in various percentages for replacing the natural aggregates in the control mix. The results show that the combined use of slag powder as an addition to the cement mass and artificial slag aggregates, regardless of the percentage of substitution of Natural aggregates in the mortar mortar mix, has led to the development of new mortar mixes with higher compaction than the control mortar. The higher filling rate due to the use of ground slag has influenced the increase of compressive strengths and freeze-thaw strengths from the repeated freeze-thaw action for new cement mortar mixes with blast furnace slag, as compared to the control mortar mix.
This study develops a new type of eco-friendly building brick so-called unfired four-hole hollow brick (UFHB) by using a mixture of ordinary Portland cement (OPC), low-calcium fly ash (FA), and different proportions o...
This study develops a new type of eco-friendly building brick so-called unfired four-hole hollow brick (UFHB) by using a mixture of ordinary Portland cement (OPC), low-calcium fly ash (FA), and different proportions of crushed sand (CS) and river sand (RS). A hydraulic-static pressure was applied to form the brick samples. The effect of various CS-RS blends on the mechanical strength of the UFHB samples was studied. In addition, the numerical method was applied to simulate the heat transfer process through the brick wall. The obtained results show that the UFHB mixture containing a mixture of 10% RS and 90% CS as blended fine aggregate registered the highest strength value in comparison with other UFHB mixtures. Moreover, utilization of the UFHB was highly effective in term of heat insulation as compared to the conventional brick.
A robust assessment on the impact of climate change at regional atmospheric condition is crucial to ensure the sustainability of groundwater resource for tropical karst island, where water is considered relatively sca...
A robust assessment on the impact of climate change at regional atmospheric condition is crucial to ensure the sustainability of groundwater resource for tropical karst island, where water is considered relatively scarce and thus important for the community. In this study, future long-term climate projection under HadCM3 global model climate (GCM) scenarios for a period of 2020-2090 is validated and simulated, using input data of weather variables downscaled by Statistical Downscaling Model (SDSM). The simulation indicated that the climate variables, i.e. temperature and rainfall, are expected to be affected by climate change and generally vary over the period under the scenarios. The rainfall is estimated to slightly raise by 0.14% and 0.09% under H3A2a and H3B2a scenarios, respectively. Steady temperature increases by 1.89-2.16% (Tmax) and 1.05-1.59 % (Tavg) and a decrease of 0.73-0.76% were predictable for all scenarios.
Accurate mapping of groundwater vulnerability zones based on robust groundwater model is crucial towards an appropriate development of management strategies. This study aimed at developing groundwater vulnerability zo...
Accurate mapping of groundwater vulnerability zones based on robust groundwater model is crucial towards an appropriate development of management strategies. This study aimed at developing groundwater vulnerability zones in a tropical karst area in Rote Island, Indonesia. HGZ method was employed to accommodate the limitation of subsurface data. Using reverse particle-tracking simulation, this study combined the simulation results (travel time and pathline trajectory) with the potential groundwater contamination risk to designate three vulnerability zones. In this study preventive management measures were recommended to ensure provision of safe and good quality water from Oemau Spring and to protect the spring from contamination.
Based on the foundation treatment engineering of Jiangyin economic development zone in Fujian province as an example, the soft soil foundation was treated by the method of surcharge preloading combination with dynamic...
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Based on the foundation treatment engineering of Jiangyin economic development zone in Fujian province as an example, the soft soil foundation was treated by the method of surcharge preloading combination with dynamic compaction. In construction process, it includes three the in-situ test of construction phase: Before inserting plastic drainage plate, after surcharge preloading and after dynamic compaction treatment. Focusing on soil mechanics parameters, pore water pressure and the foundation bearing capacity test, and analyzes the change trend of all the soil parameters of different stage. A variety of in-situ test results show that this method can not only greatly improve the bearing capacity of foundation soil, but also provides technical support for further in-depth study of the method of reinforcement mechanism and the optimization design.
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