bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Restoring Force Models of Steel High Performance Concrete Composite Structural Wall
Authors: Bai Liang , Zhou Tian Hua , Liang Xing Wen
Published: July 2012

Steel high performance concrete (SHPC) structural wall was a combination of steel and high performance concrete. They can give full play to the advantages of steel and high performance concrete and have better dynamic behavior. Several specimens of SHPC structural walls with different parameters were tested under constant axial loading and horizontal cyclic loading. The testing phenomena and failure mechanics of those walls were compared and analyzed. On the basis of theoretic formulas and testing data, the main characteristic points and the law of stiffness degradation were presented, then, the tri-linear and four linear restoring models were built and provided. At last, the calculation formulas of stiffness parameter in restoring force model at different stages of deformation were presented. The results show that the declined strength stage of skeleton curve of specimens is related to the yielding strain of boundary steel, axial load ratio and stirrup content. The restoring force model of SHPC structural wall is thus formed for the application of nonlinear dynamics analysis as well as static structural calculations.
Particle Packing Density and Limestone Fillers for More Sustainable Cement
Authors: He Huan , Courard Luc , Pirard Eric
Published: July 2012

Cement blending with mineral admixtures, especially with byproduct or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was proposed to replace of coarse cement grains by the inert fillers for sustainable cement in the low w/c concrete cement. As a basic mechanism, particle packing plays an important role in such replacement or blending. In the first part of study, the paper discusses the particle packing aspect of cement grains, limestone filler (LF) and LF blended cement. The new developed wet packing method and a dry packing method are proposed for the evaluation purpose. The paper presents results of packing tests with the influences of PSD, cement type, vibration, mixing, blending proportions, etc. The advantages and limitations of two packing methods are also discussed in this paper.
Pastes Prepared with Sulfonate, Chalcedony and Sugar
Authors: Bezerra Ulisses Targino , Barbosa Normando Perazzo
Published: July 2012

Papers presented at ICPIC 2010, Madeira Island, Portugal, dealing with the use of polymers in cementitious materials, show the need to combine different admixtures to optimize the properties of cement. This work is a continuation of a paper presented at NOCMAT 2010, Cairo-Egypt, about the incorporation of several materials in Portland cement to increase mechanical properties and workability. The best performance admixtures were chosen and they were combined considering the superposition of effects. Cement pastes were prepared with chalcedony and sulfonate (to increase compressive strength) and sugar (to increase workability). Two percent of cement was replaced by the admixtures. The water/cement ratio was constant and equal to 0.44. Results show that the combination of 0.05% of sugar and 1.95% of sulfonate and 0.10% of sugar and 1.90% of chalcedony produced a paste with the greatest compressive strength and good workability. Compression strength was respectively 27.4 MPa and 36.6 MPa, which represent increases of 33.5% and 78.6%, respectively, relative to the reference paste without admixtures. While increasing the paste compression strength with sulfonate has been significant, the results of the paste with chalcedony were the more surprising because the water/cement ratio of pastes was kept constant. The chalcedony is a type of crystalline silica, which shows deformation in their structure. So because of crystalline structure of chalcedony, there should be, probably, no significant reactivity of it with the cement hydrates, just the fact that its structure be deformed can explain this reactivity. The most important conclusion concerns is that the combinations of admixtures can improve a lot the properties of Portland cement paste.
Experimental Study of Glubam Single-Bolted Joint Loaded by Tension
Authors: Yang R.Z. , Xiao Yan
Published: July 2012

Glubam is a new construction material and glubam bolted joints have been developed in modern bamboo structures. To observe the performance of bolted joint, two major groups of glubam-single-bolted-joint specimens with double steel side plates are tested. Bearing strength and failure mode are analyzed and discussed. It is shown that specimens with tension parallel to bamboo fiber always yield by shearing out and showed higher bearing strength as well as better ductility, while specimens with tension perpendicular to bamboo fiber will fail by net tension. Results of bearing strength are evaluated by the 5% off-set method. At the end, equations obtained from test data and analysis about yielding strength of glubam bolted joint was obtained for following study and project design.
Developing Low CO2 Concretes: Is Clinker Replacement Sufficient? The Need of Cement Use Efficiency Improvement
Authors: Damineli Bruno Luís , John Vanderley Moacyr
Published: July 2012

Cement industry is under stress for mitigating CO2 emissions: it is responsible for around 5-7% of total global emissions due to the production that went over 2x109 tones in 2006. And this prospect will aggravate since it is expected, for 2050, an increase of 2.5 times, which will make cement industry guilty for more than 30% of CO2 emissions. Main actions for decreasing emissions are: energy efficiency in kilns, use of alternative fuels and clinker substitution. These, however, are not capable to decrease emissions in a satisfactory way. CO2 capture is expensive and could increase cement costs. The pressure, which is increasing all over the world, will certainly strike concrete producers. The optimization of cement use in concrete is an undeveloped strategy that can provide a huge contribution. For its development an international and cooperative effort is crucial. This paper proposes to change the focus from the cement production optimization to optimization of concrete production industry, responsible for most of cement consumption. It is discussed the limits of clinker substitution by mineral admixtures, comparing the expected cement demand increase versus the availability of these alternative materials, concluding that, despite the importance of this strategy, it is actually not capable for mitigating cement CO2 emissions in a satisfactory way. It is discussed and assessed technical possibilities and limits of optimization of cement content in concrete, based on literature data analysis using two new environmental indicators Binder Intensity and CO2 Intensity. There is a potential to reduce significantly the cement content on concrete, being possible to increase concrete production without increasing cement production and CO2 generation. This can impact significantly on concrete environmental load to global warming and also in its cost, making possible to increase popular habitations construction mainly in some developing countries which have a lack of different sort of infrastructure where concrete technology is still dominant.
Corrosion of Permeable Concrete under Simulated Acid Rain
Authors: Guo Hui Fang , Song Zhi Gang , Yang Sheng Yuan
Published: July 2012

A long time immersion test of concrete specimens in dilute sulfuric acid is carried out to study the permeable concrete material aging rule under the action of the sulfuric acid. The experiment is designed by uniform design containing 4 factors and 10 levels and the soaking solution pH value is 4.00. To measure acid consumption, titration sulfuric acid with concentration of 0.125mol / L is used to keep original pH value of soaking solution, through which the corrosion rate of specimens can be determined. After certain immersion time, the specimens are dried and weighted and the weight changes of the specimens are recorded. The results show that corrosion rate of permeable concrete shares the same family of corrosion rate functions with those of ordinary concrete and mortar. However, the weight of specimen fluctuates with the soaking time, so that it may not be a proper index of corrosion.
The Study of Alkaline-Activated Magnesium Slag Cementitious Material
Authors: Xiao Li Guang , Luo Feng , Li Rui Bo , Liu Chang Yu
Published: July 2012

Magnesium slag cementitious material was prepared successfully using the magnesium slag-furnace slag-clinker system and different activators in this paper. The effect of activator on the mechanical property of the material was studied. The hydration and microstructure of this composite cement were analyzed by X-ray diffraction and scanning electron microscopy and the interaction mechanism was researched. The results show that the activity of magnesium slag was enhanced significantly by adding a small amount of activator. Combined activators have the best effect. The hydration products of magnesium slag cementitious materials mortar were C-S-H, Aft and Ca (OH)2 and so on.
Influence of Corn Straw Fibers and Polymer Latexes on Vibration Damping Property of Cement-Based Materials
Authors: Xiao Li Guang , Li Yuan Chao , Li Rui Bo
Published: July 2012

The effectiveness of corn straw Fiber, organic polymer latexes, organic polymer latexes and corn straw Fiber blending on vibration damping properties of cement-based materials were studied by filling organic polymer latexes, and corn straw Fiber. The functional mechanisms of various fillers were discussed. The experimental results showed that the vibration damping ratio of cement-based materials with organic polymer latexes is 149.77% higher than that of pure cement-based materials, the vibration damping ratio of cement-based materials with corn straw fiber is 152.58% higher than that of pure cement-based materials, the vibration damping ratio of cement-based materials with organic polymer latexes and fibers blending is 191.08%, also higher than that of pure cement-based materials. The impact of corn straw Fiber and polymer latexes modification on the microstructure and mechanisms were analyzed by FTIR and SEM.
Hysteresis Analysis on Beam-Column Connection of Concrete-Filled Steel Tubular Structure under Cyclic Loading
Authors: Qu Hui
Published: July 2012

The concrete-filled steel tubular structure is widely used in practices, as it shows perfect seismic performances such as ductility, and has strong ability of collapse under seismic loading. In this paper, firstly, the stiffness damage and stiffness recovery parameters of concrete constitute model under cyclic loading was calibrated and verified by examples. Then the finite element model was verified by numerical examples of reinforce concrete members and concrete-filled steel tubular members. At last, on the base of the result of analysis and verification, the hysteresis curves on beam-column connection of concrete-filled steel tubular structure under cyclic loading were simulated and compared with experimental results, and the hysteresis characters was analyzed in the end.
Potential Use of Colloidal Silica in Cement Based Composites: Evaluation of the Mechanical Properties
Authors: Santos S.F. , Rodrigues J.A. , Tonoli G.H.D. , Almeida A.E.F.S. , Savastano Holmer
Published: July 2012

The properties of cement based composites depend not only on the properties of their individual components but also on their interfacial characteristics and transition zone between fiber and matrix. There has been a renewed interest in the use of cellulosic pulp as micro-fiber reinforcement in cement based composites. The addition of nanoparticles, such as colloidal silica, to fiber-cement could allow a better control of its microstructure and the enhancement of the matrix/fiber interface. The objective of this work is to evaluate the effects of colloidal silica on the microstructure and mechanical performance of cementitious matrices and fiber-cement composites. These cementitious materials were prepared with 0%, 1.5%, 3%, 5% and 10% w/w colloidal silica suspension content. Cementitious matrices without fibers were produced by vibration. Fiber-cement composites with unbleached Eucalyptus kraft pulp as a micro-fiber reinforcement were produced by the slurry dewatering technique followed by pressing. All composite materials were cured by water immersion. A splitting (Brazilian) test was carried out to determine the tensile strength of cementitious matrices. Mechanical behavior of the fiber-cement composites was evaluated via modulus of rupture and fracture toughness based on load-displacement curves (L-d curves) under continuous loading and 3-point bending arrangement. The energy of fracture was measured through a stable crack propagation test with SENB (single-edge notched bending) configuration also under a 3-point bending arrangement. The matrix with highest content of colloidal silica suspension (10% w/w) presented high values of water absorption and consequently presented the lowest splitting tensile strength. The average values of modulus of rupture and fracture toughness of fiber-cement tend to decrease with increasing colloidal silica content. However, the pullout mechanism increased significantly in the fiber-cement composites with additions between 3% and 10% w/w of colloidal silica suspension as compared to that without any addition, noted by degree of improvement in the energy of fracture and by scanning electron microscopy micrographs (SEM). These findings show the potential use of colloidal silica to improve the transition zone between the cellulosic fiber and the cementitious matrix. The results of this study show an important way to engineer and control the fracture process of the composites.
Experimental Study on All-Lightweight Aggregate Concrete Columns under Eccentric Loading
Authors: Yang Yan Min , Zhang Hao
Published: July 2012

A kind of lightweight sand was only used as the fine aggregate to make the all-lightweight aggregate concrete, which can significantly reduce the gravity load of a structure and the foundation loads. Accordingly, the application of all-lightweight aggregate concrete in the construction projects can reduce the cost of foundation as well as construction project. In order to develop a new multi-story structural system which has a multifunction of load-bearing, lightweight and energy saving, the paper carried out an experimental study on the mechanical behaviors of six all-lightweight aggregate concrete columns with symmetrical reinforcement under eccentric loading. The failure modes, deformation characteristics and load-bearing capacity of the columns were analyzed. The effect of reinforcement ratio, stirrup ratio and eccentricity on the mechanical behaviors of the columns under eccentric loading were discussed. The test results show that all-lightweight aggregate concrete columns were loaded to failure with high load-bearing capacity and good ductility. The excellent mechanical behavior and the possibility of replacing the normal concrete with all-lightweight aggregate concrete were verified.
Experimental Study on Flexural Behaviors of All-Lightweight Aggregate Concrete Beams and Slabs
Authors: Yang Yan Min , Zhang Hao
Published: July 2012

The use of lightweight and energy saving materials is the main trend of modern building and construction technology. All-lightweight aggregate concrete, which is a new type of lightweight aggregate concrete, not only has all the advantages of light weight concrete but also a lower apparent density of 600kg/m3. At present, the commonly-used energy-saving organic insulation materials include the EPS insulation and polyurethane insulation. The paper presents a new type of all-lightweight inorganic aggregate concrete by replacing organic material, in order to obtain a lightweight, energy-efficient building structure which synthesizes the load-bearing capacity, lightweight and energy-saving. Tests on the flexural behaviors of 11 all-lightweight aggregate concrete beams and 6 slabs were conducted. The effects of steel reinforcement ratio and loading distribution on the flexural and shear behaviors and method to calculate the load carrying capacity were carried out. The feasibility of application of all-lightweight aggregate concrete on multi-story buildings and to replace common reinforced concrete members in bending was discussed. The experimental study in the paper can provide a basis of the lightweight and energy-saving multi-story structure.
Influences of Ground Limestone Fineness on the Properties of Cement-Based Materials
Authors: Xiao Jia , Ma Bao Guo , Dong Rong Zhen , Xu Cai Yun
Published: July 2012

The effect of ground limestone fineness on the properties and mechanism of cement-based composite materials was investigated. The setting times, fluidity and strength of cement mortar were measured. In order to identify the mechanism effect of ground limestone fineness on the microstructure of the hardened cement pastes, microstructure analyses such as calorimetry analysis and Mercury Intrusion Porosimetry (MIP) were also performed. Experimental results indicated that the setting times are shortened, and the fluidity and strength of cement mortar are improved with the ground limestone fineness increases. The increase of the ground limestone fineness can effectively inhibit the pore structure of hardened paste, which due to mortar and paste samples incorporating replacement levels of ground limestone, and improve the pore structure of hardened paste.
Hygrothermal Performance of an Experimental Hemp-Lime Building
Authors: Lawrence Mike , Fodde Enrico , Paine Kevin , Walker Pete
Published: July 2012

The use of hemp-lime as a construction technique is a novel approach which combines renewable low carbon materials with exceptional hygrothermal performance. The hemp plant can grow up to 4m over a four month period, with a low fertilizer and irrigation demand, making it very efficient in the use of time and material resources. All parts of the plant can be used the seed for food stuffs, the fibre surrounding the stem for paper, clothing and resin reinforcement, and the woody core of the stem as animal bedding and aggregate in hemp-lime construction. The unique pore structure of the woody core (shiv) confers low thermal conductivity and thermal and hygric buffering to hemp-lime. The construction technique promotes good air tightness and minimal thermal bridging within the building envelope. All these factors combine to produce low carbon, hygrothermally efficient buildings which are low energy both in construction and in use, and offer opportunities for recycling at end of life. This paper reports on the hygrothermal performance of an experimental hemp-lime building, and on the development of a computerized environmental model which takes account of the phase change effects seen in hemp-lime.
Mechanical Properties of Glubam Sheets after Artificial Accelerated Aging
Authors: Shan Bo , Chen Jie , Xiao Yan
Published: July 2012

Glubam is a kind of environmentally friendly and energy efficient composite material in civil engineering developed in recent years. But the mechanical performance after subjected aging under the outdoor conditions is a blank of research field. In this paper, a new artificial accelerated aging test method and equipment for glubam have been presented by authors. The basic material performance, including deformation changing, tensile properties, compressive properties, bending properties and internal bonding strength, are tested according to the equivalent aging duration of 120 days, 240 days, 480 days and 960 days. The failure mode of specimens shows that delamination of glubam caused by dry wet circulation is the main reason for mechanical properties degradation. All test results present monotone decreasing trend and the internal bonding strength is the most sensitive to aging duration. Aging influence factor β, internal bonding correlation coefficient η and internal correlation coefficient θ can be used to evaluate aging performance of glubam, but the accuracy of evaluation results need further research.
Variables Involved in the Planting of Rice in the Rice Husk
Authors: Akasaki J.L. , Silva E.J. , Sousa L.C. , Melges J.L.P. , Tashima M.M. , Payá J.
Published: July 2012

Rice production in Brazil in 2010 was approximately 12,2 million tons, and to reach that amount several planting techniques were used with different strains of rice in different rice-growing areas. Since Rice Husk Ash (RHA) is the pozzolan of vegetable origin most studied by researchers working in the area of pozzolanic materials, the present paper evaluates the influence that the form of planting, the climate, the soil, the strain of rice and the origin/amount of nitrogen-based fertilizers used in rice cultivation has on the chemical composition and crystallographic properties of RHA. The results obtained in this paper, confirm the importance of carrying out routine chemical analysis and X-Ray diffraction to maintain the quality control of the CCAs produced, because in situations of large-scale production, husks of different origins may be used.
Extruded Cement Based Composites Reinforced with Sugar Cane Bagasse Fibres
Authors: Teixeira Ronaldo Soares , Tonoli G.H.D. , Santos S.F. , Fiorelli Juliano , Savastano Holmer , Lahr F.A. Rocco
Published: July 2012

The extrusion process can produce composites with high-density matrix and fibre packing, low permeability and fibre matrix bond strengthening. This process is also compatible with the use of vegetable fibres as raw materials in the production of cost-effective construction elements such as ceiling panels. Sugar cane bagasse fibres (SCF), one of the largest cellulosic agroindustrial by-products of sugar and alcohol industry available in Brazil, are a renewable resource usually used as a biomass fuel for the boilers. The remaining bagasse is still a source of contamination to the environment, so there is a great interest on exploiting novel applications to sugar cane bagasse fibres. In this work, the effect of SCF on extruded cementitious composite performance was evaluated. Three different contents of SCF were considered, using cellulose pulp as secondary micro-reinforcement to improve the resistance to the appearance of microcracks. Composites were prepared using a laboratory Auger extruder with vacuum chamber and were tested after 28 days of water curing and after 200 accelerated ageing cycles. Modulus of rupture (MOR) and Tenacity (TE) of extruded composites were assessed by four point bending test. Water absorption and apparent volume were determined by water immersion. Microstructure behavior was evaluated by mercury intrusion porosimetry and scanning electron microscopy (SEM). Results indicated that the introduction of larger fibres increased tenacity (TE) at 28 days and favored a higher amount of macropores (0.1 to 1 mm); SEM observations confirmed that fibre degradation occurred after 200 cycles.
Effects of Methane Cold Plasma in Sisal Fibers
Authors: Barra Bruna , Paulo Bergo , Alves Junior Clodomiro , Savastano Junior Holmer , Ghavami Khosrow
Published: July 2012

One of the main problems in using vegetable fibers as reinforcement in aggressive cement matrix is the penetration of alkaline products in the porous structure of the filaments, making them very fragile with the time. In this sense a series of physical and chemical methods of surface modification has been used in order to improve its characteristics. The plasma surface modification technique is a physical method surface modification that utilizes ionized gas at low pressure to change the chemical nature and the substrate surface morphology of both organic and inorganic materials without changing their intrinsic properties. This is considered an environmentally friendly process without generation of contamination and has a low operating cost compared to some chemical (such as silane based) treatments. In the present study, the sisal fibers were treated with methane plasma generated by direct electric current during 10, 20 and 30 min with gas flow of 5 cm3/s and current of 0.10 A. The study presents some mechanical, physics and chemical characteristics of sisal fiber after being subjected to treatment with methane cold plasma. The results presented indicate that treatment with methane cold plasma induced changes in sisal fibers at all times of exposure to treatment (10, 20 and 30 min). However, the major changes in structural and mechanical components may be seen in fibers treated with 10 min of exposure to plasma.
Characterisation of Lime/Metakaolin Paste Using Impedance Spectroscopy
Authors: Ball Richard J. , Pesce Giovanni L.A. , Bowen Chris R. , Allen Geoffrey C.
Published: July 2012

This paper describes the study of lime/metakaolin pastes using impedance spectroscopy during the first three weeks after mixing. Changes in the composition, structure and morphology were obtained using scanning electron microscopy, energy dispersive analysis of X-rays, differential scanning calorimetry, thermal gravimetric analysis and mercury intrusion porosimetry. The impedance data was studied with reference to changes in ac conductivity, relative permittivity and bulk resistance. Electrical behaviour was found consistent with structural and compositional changes. This study highlights the importance of impedance spectroscopy as a method for the non destructive monitoring and evaluation of lime based hydraulic binders.
Mechanical Strength of Lime-Rice Husk Ash Mortars: A Preliminary Study
Authors: Méndez R. , Borrachero M.V. , Payá J. , Monzó J.M.
Published: July 2012

Rice is produced in many countries in the world, and this product permits to feed a lot of people, most of them in developing countries. Approximately one tone of rice produces 200 Kg of rice husk, and when this rice husk is burnt 20% of rice husk ash (RHA) is obtained. A very important part of rice husk is abandoned in the field producing environmental problems. RHA can be obtained by controlled combustion, when this fact occurs, a good quality RHA is produced. This RHA can be used as a pozzolanic material in mixtures with lime or Portland cement, producing good mechanical properties and durability. In this work a preliminary results about the influence of RHA/lime ratio on workability and mortars strength was studied. The results showed that mortars workability improves when RHA/lime ratio do. Compressive strength (Cs) of mortars with different RHA/lime ratios was studied, in this sense, for 28 days curing time at 20°C an increase of Cs when RHA/lime ratio do is observed. However for 90 and 180 days curing time a maximum or Cs for RHA/lime equal to 2 is obtained. The lowest and highest Cs values obtained were 6 and 18 MPa respectively, when 20°C curing temperature was used. When curing temperature increases until 65°C similar tendency of Cs respecting RHA/lime ratio was observed. A preliminary study of binders for using in mortars tiles reveals that at least low quantities of Portland cement must be included in binder composition in order to obtain short term strengths that make easy tile demoulding process.
Light Weight Earth Material and its Application in the Alteration of Log Dwellings
Authors: Yang Jing Ning , Shen Gao Feng , Bai Wen Feng
Published: July 2012

In the construction of log building, the building's insulation effect is mainly achieved by the timber tightly connected, which usually requires a large flat timber that lead to the consumption of high-quality wood.In recent years, by the decline in quality of forest resources, existing log buildings are constructed with fast-growing wood which small diameter, and larger curvature. Compared with the traditional log building, the log wall constructed with fast-growing wood has wider gap, poor insulation and poor pest control.So it greatly increased consumption of firewood for heating.To compensate for this defect, this paper make a study of log building constructions wall structured with light weight earth material. Mixture of plant fibre and cement, is used as main reinforce component, together with raw soil to enhance the ability of anti-cracking and heat preservation, fixing the mixture of ligth clay on inner side of the construcion's wall to enhance the ability of heat preservation and getting smooth wall surface by fill the gap in the wall, and easy for decorating interior wall.
Research on the Self-Leveling Mortar Made of Tailings
Authors: Chen Yu , Li Qiu Yi , Liu Jian Min , Yue Gong Bing
Published: July 2012

To improve the utilization of tailings, the basic properties of tailings and theirs influence on self-leveling mortar performance are experimental studied in this paper. The results show that the tailings can completely replace the natural sand to produce self-leveling mortar since the advantages of better fluidity, less water consumption, smaller time loss and high strength. The strength decreases with the addition of mineral admixtures, but it can still satisfy the requirements of standard JC/T 985-2005 "Cementitious self-leveling floor mortar ". Moreover, this method reduces pollution and production costs effectively.
Experimental Buckling Capacity of Multiple-Culm Bamboo Columns
Authors: Richard Michael J. , Harries Kent A.
Published: July 2012

This paper presents the experimental results of an on-going study investigating the buckling capacity of single-culm and multiple-culm bamboo column elements. Four single-culm columns of species Bambusa Stenostachya were tested to obtain single-culm column capacities as well as control tests to determine the behaviour of short-doweled end-conditions. Three multiple-culm columns were then tested in order to investigate the ultimate capacity and buckling behaviour of these elements. Specifically of interest wasthe effect of bamboo stitching on improving column behaviour in the bamboo culms. Experimental values were compared with theoretical predictions for buckling capacity using the Euler equation. The behaviour of multiple-culm columns was shown to exhibit load redistribution and to mimic the sum of individual culm capacities rather than composite column behaviour. Stitching was shown to be beneficial in enforcing column geometry yet detrimental through introduction of lateral loading to culms. Finally, the apparent effective length factor K was shown to be closer to K=1 than to the value obtained from control tests of the designed end condition.
Reuse System of Building Steel Structures - Structural Performance of Reusable Members and Practical Examples
Authors: Fujita Masanori
Published: July 2012

Longevity, reuse and recycle can be effective in reducing environmental burden in the life cycle of building steel structures. Longevity is the most crucial element in reducing the environmental burden of building steel structures. Nevertheless, there are always a number of buildings that need to be demolished for physical, architectural, economic, and social reasons. When such building steel structures have been demolished in the past, their structural members have been scrapped for recycling. Steel, by nature, is the only type of structural member that can be fabricated. Even without special joints that facilitate demolition work, steel members can be reused after minor fabrication procedures such as cutting, drilling, and welding. In this paper we discuss structural performance of reusable members and practical examples using reusable members.
Seismic Test on a Damaged Structure with Recycled Concrete Blocks
Authors: Xiao Jian Zhuang , Wang Chang Qing
Published: July 2012

A man-made damaged model of a one-storey block masonry structure with recycled aggregate concrete (RAC) was tested on a shaking table The Wenchuan earthquake wave, El Centro earthquake wave and Shanghai artificial wave were selected and input to the model with different earthquake levels in the shaking table tests. The recycled aggregate concrete (RAC) block masonry structure was damaged firstly by cutting the tie columns and its seismic behavior was experimentally investigated. The dynamic characteristics, the displacement response, the acceleration response were record. In comparison with the intact model, there is an obvious decrease in the seismic performance of the RAC block masonry man-made damage model.
Lignocellulosic Composites Made from Agricultural and Forestry Wastes in Brazil
Authors: Mendes Lourival Marin , Mendes Rafael Farinassi , Tonoli G.H.D. , Bufalino Lina , Mori Fábio Akira , Guimarães Júnior José B.
Published: July 2012

The Brazilian market of wood panels is in a consolidation process and presents great dynamism, which requires the search for new alternative raw materials that may contribute in quantity and quality to the continuous increase of this economic sector. Transforming residues generated by Brazilian agricultural industry and forestry sector into high quality panels is an interesting solution for solving raw material demand problem. The present work aims to show the potential of different types of residues for panel production showed in several research works, which were conducted in the Experimental Unit of Panel Production (UEPAM) located at the Federal University of Lavras (UFLA), Minas Gerais state, Brazil. According to results obtained, sugarcane bagasse, candeia wood and castor oil bean husk were the most promissory residues for particleboard production among the materials studied.
Seismic Behavior Test of Recycled RC Frame Column with Different Axial Compression Ratios
Authors: Fan Jin Song , Zhou An , Chen Li Hua , Liu Bing Kang
Published: July 2012

Recycled concrete is a kind of new construction materials, and now received more and more attention from researchers and engineers, since its application in engineering projects can well cater to the increasing requirements of development for economic and environment-friendly society. Based on the pseudo static test of five recycled reinforcement concrete frame columns with different experimental axial compression ratios from 0.3 to 0.65, their failure modes, failure mechanism, hysteretic behavior, skeleton curves, bearing capacity, rigidity, ductility and energy dissipation capacity were discussed. Some possible influence factors and disciplines were also selected and analyzed. The study indicates that recycled reinforcement concrete frame columns in the case of relative low axial compression ratios usually exhibited similar and steady mechanical properties with common concrete columns. With the increase of axial compression ratio, its ductility and energy dissipation capacity are decreased and destruction forms tended to obvious brittle fracture, though its bearing capacity could slightly rise. The test results and analysis also manifest recycled concrete had expectative application potentials in most case.
Availability of Resilient Modulus and Permanent Deformation Laboratory Tests of Stabilized Soil with Coal Ashes for Pavements Base
Authors: Lopes L.S.E. , Vargas P. , Casagrande M.D.T. , Motta L.M.G.
Published: July 2012

Fly and Bottom ash a coal combustion residue of thermal power plants has been regarded as a problematic residue all over the world. This study presents the results of testing for resilient modulus and permanent deformation to evaluate the mechanical properties of a soil stabilized with fly or bottom ashes, with and without lime addition. The soil tested is a regional sandy soil, which is not suitable for use in pavement works. The addition of fly ash with lime improved their mechanical properties, these being dependent on the ash content, moisture and number of load cycles. However in the mixtures only with ashes, the improvement was lower than the mixtures with ashes and lime. It was performed a paving project to assess their competitiveness as a base material for pavements. The results of this project showed that the soil stabilized with ashes is competitive for low volume traffic roads, with the advantages of minimizing the environmental problems caused by coal ash disposal.
Pseudo-Static Experiment Study on Recycled Concrete High Shear Walls
Authors: Chen Li Hua , Zhou An , Liu Bing Kang
Published: July 2012

The low-cyclic loading tests are carried out for three pieces of recycled concrete high shear walls, with 100% replacement ratio of recycled coarse aggregate under different axial-load ratios. The mechanical performances of shear walls, including failure patterns, the bearing capacity, the hysteretic properties and ductility, are analyzed. The test results indicate that the basic behavior of recycled concrete shear walls resembles quite closely that of the ordinary concrete shear walls, the recycled concrete shear wall under bending failure has good ductility and bearing capacity; the hysteresis loop is stable and the degradation of stiffness is not great; the shear-slip phenomenon becomes significant and the ductility decreases under high axial-load ratio. The calculation of flexural strength of recycled concrete shear walls can be adopted directly from computational theories and formula used for ordinary concrete shear walls. It is feasible to apply reasonably designed recycled concrete shear walls to small high-rise buildings.
Experimental Study on Compressive Performance of R.C. Columns with Recycled Aggregate
Authors: Hao Tong , Zhao Lin Tao , Du Zhao Hua
Published: July 2012

This paper presents the test results of 12 R.C. columns with recycled aggregates under axially loading and eccentrically loading, the dimensions of the column are width b=150mm, depth h=200mm and height l=1400mm, the recycled aggregate replacement rate of the concrete are 0%, 50% and 70% respectively, the concrete strength is of C40 grade. The compressive performance such as the strain of concrete and longitudinal reinforcement, the failure modes and the compressive bearing capacity of the R.C. columns with recycled aggregates are analyzed, and compared with the R.C. columns made of ordinary concrete. The results show that the compressive performance such as the loading process, the failure modes and the bearing capacity of the R.C. columns with recycled aggregates are almost the same as that of the columns with natural aggregate, the compressive bearing capacity of R.C. columns with recycled aggregates may be calculated by the stipulations of Chinese current design Code (GB50010). This may be as a reference for the application of the concrete with recycled aggregates in engineering.
Experimental Study on Fatigue Behavior of Prestressed Concrete Beams with Manufactured Sand
Authors: Li Qian Qian , Liu Li Xin , He Sheng Dong
Published: July 2012

This paper presents the test results of 2 prestressed concrete beams with manufactured sand under cyclic loading, the concrete is made of manufactured sand to replace natural sand with different replacement rates of 50% and 100%. The stress of re-bars and prestressed strands and the strain of manufactured sand concrete are discussed, the rigidity and cracking of the prestressed beams under cyclic loading are analyzed, and the flexural behavior of the beams after 2.5 million times cyclic loading are also discussed and analyzed. The results show that the fatigue behavior of the prestressed concrete beams with manufactured sand to replace the natural sand under cyclic loading is satisfied, the flexural bearing capacity of the prestressed beams after 2.5 million times cyclic loading is still sufficient. The results also show that the crack width and the mid-span deflection of the prestressed beams are in the allowable range at the serviceability limit state. This may be regarded as a reference for the applications of manufactured sand in the prestressed concrete structure .
Experimental Study on Flexural Property of Reinforced Concrete Beams with Recycled Aggregate of Construction Waste
Authors: Du Zhao Hua , Hao Tong , Liu Li Xin
Published: July 2012

This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of and with different recycled aggregate replacement rate. The results indicate: the ultimate bearing capacity of recycled concrete beams with natural aggregate concrete beams are almost the same, and can meet the requirements of chinese code; The cracking resistance of the reinforced recycled concrete beams is slightly less than that of the beams with natural aggregates, the influence of recycled aggregate replacement rate to cracking resistance is not obvious. Recycled concrete beam crack load the calculated value is greater than the measured value, should carry out the theoretical value adjustment. Reinforced concrete beams is one of concrete structures, its the most common and most important component, Study of flexural property of reinforced concrete for recycled concrete structure component in the popularization and application to have the important significance [. This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of C30 and C40 and with different recycled aggregate replacement rate of 0%, 50% and 70%. These results may be as a reference for the application of the concrete with recycled aggregates of construction waste in engineering [2,3,.
Compared Research on Elastic Modulus Strength between Manufactured Sand Concrete and Ordinary Concrete
Authors: He Sheng Dong , Liu Li Xin , Li Qian Qian , Zhang Zhi You
Published: July 2012

Now, the resource of high quality natural sand is lacking. Manufactured sand is broken by rocks or tailings, which could be used in the mixture of cement concrete as fine aggregate instead of natural sand. The use of manufactured sand in concrete structure has become more and more important. It can make construction industry develop with environmentally friendliness and sustainability. In this paper, the elastic modulus strength was compared between manufactured sand concrete and ordinary concrete by testing on concrete specimens using the manufactured sand, the replacement ratios of manufactured sand by mass to the natural sand are 0, 0.30, 0.5, 0.70 and 1.0 respectively. The experimental research showed that the elastic modulus strength of manufactured sand concrete was stronger than that of natural sand and it had an increasing trend with the increasing of replacement rate and age but the elastic modulus of replacement rate of 50% was largest. This showed that the optimum replacement ratio was 50%.The fitting relations between elastic modulus and compressive strength was different with that of ordinary concrete. The relationship equation between elastic modulus strength and compressive strength of manufactured sand concrete was recommended in this paper. This could be used as a reference for the applications of the concrete using the manufactured sand as a fine aggregate in engineering.
Activation Alkaline Waste Kaolin for Fabrication of Building Blocks
Authors: Gomes K.C. , Rocha Bruno Diniz , Ferreira Debora T.A. , de Lira Elder Cunha , Torres Sandro Marden , de Barros Silvio Romero , Barbosa Normando Perazzo
Published: July 2012

In the state of Paraíba, one of the activities of great economic importance is that of the kaolin processing industry. This type of processing generates large amounts of waste that are displayed randomly in the environment, which has attracted attention, because the environmental impact caused by it and the lack of established process of recycling. The University Federal o Paraíba has been developing several research to explore the potential for recycling of industrial waste from Paraíba, mainly waste of kaolin. This research have pointed to the feasibility of using waste as aggregate and pozzolan in the development of mortars use multiple. These wastes have different size fractions, depending on the stage of processing: a sandy (termed in this study of RGC) containing mainly quartz, mica and calcite; and other clay (termed in this study of RFC) is thinner, containing higher amounts of kaolinite. This study aims to evaluate the potential of alkaline activation from waste kaolin (RGC and RFC) by comparing the activation using sodium silicate and hidroxide of calcium. With the objective of studying the potential of waste as a material pozzolanic, it was processing through grinding at 80.000, 60.000, 40.000, 20.000 and 10.000 rotations and with the purpose of evaluating the reactivity of materials, these wastes were calcined at 750°C/2h. For the mechanical characterization was using an equipment universal testing of Shimadzu Servopulser, where it was observed that only RFC, when calcined, developed strength in both activations, and the activated with silicate sodium with higher strength. The RGC, both in the state in natura and calcined did not show satisfactory mechanical strength to the test under the conditions of synthesis used in this research. Thus, the waste RFC's studied in this work has the potential to be used as constituent materials for building blocks in terms of its mechanical properties.
Durability Evaluation of Agro-Industrial Waste-Based Particle Boards Using Accelerated Aging Cycling Tests
Authors: Garzón Nubia , Sartori Diogo , Zuanetti Igor , Barbirato Gui , Ramos Rafael , Fiorelli Juliano , Santos S.F. , Savastano Holmer
Published: July 2012

The degradation of agro-industrial waste-based particle boards reinforced with sugar cane bagasse was evaluated by comparing their physical and mechanical properties. The particle boards were prepared with sugar cane bagasse particles (85% by weight of composite) and mixed with bi-component polyurethane resin based on castor oil (15% by weight). After mixing for 2 to 3 min, the resulting mixtures were pre-pressured. Standard molding conditions were: temperature, 100°C; pressure during heating, 5 MPa; and heating time, 10 min. The dimensions of the particle boards produced in the laboratory were 0.40 m x 0.40 m x 0.01 m. The boards were cut into testing specimens with dimensions 0.25 m × 0.05 m × 0.01 m. The accelerated aging test was carried out based on the ASTM D 1037 standard in order to determine the main factors that cause degradation and to identify their influence. The test consists of cycles of six treatment steps, i.e., immersion in water at 49°C for 1 h, steaming at 93°C for 3 h, freezing at-12°C for 20 h, drying at 99°C for 3 h, steaming at 93°C for 3 h, and drying at 99°C for 18 h. This cycle was applied six times for all specimens. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), water absorption (WA%) and thickness swelling (TS%) were measured before and after the cycles of accelerated aging. The performance of the particle boards before accelerated aging presented acceptable mechanical performance, MOR: 21.86 ± 2.16 MPa, MOE: 2.77 ± 0.26 GPa, and IB: 1.18 ±0.40. The performance of the particle boards decreased after accelerated aging showed, MOR: 6.25 ± 0.70 MPa, MOE: 0.52 ± 0.10 GPa, and IB: 0.15 ± 0.07. The results were influenced by the temperature, relative humidity and warm water. After the accelerated aging process, the materials showed mechanical behavior similar to Low-Density grade Particleboard (LD1).