Autoclaved Lightweight Concrete Research Articles

원심모형실험을 이용한 경량포장체의 거동특성

일반적으로 국내에서의 경량기포콘크리트는 건축용 온도구조용 단열재나 토목용 폐공 채움재, 터널의 뒤채움재 등으로 사용되고 있으며 기타 사무실 바닥 충전재, 경량블록제조 등으로 사용되어지고 있다. 이러한 경량기포콘크리트의 사용범위를 확대하여 연약지반에 도로건설시 등간격으로 말뚝을 설치하여 기층으로 사용하는 공법을 연구중에 있다. 본 연구에서는 경량포장체의 연약지반에서의 거동 특성을 분석하기위해 지오센트리퓨지 시험을 이용하였다. 실제 포장체를 1/30로 축소한 슬래브 형태의 모형을 카올리나이트로 조성된 연약지반에서 시험을 실시하였다. 말뚝 배열은 무리말뚝(36본 <TEX>$3{\times}12$</TEX>)로 제작하여 사용하였다. 시험 중력 레벨은 실중력의 30배로 원심력을 작용하여 실험하였으며 이때 작용하는 경량포장체 모형의 거동특성을 바탕으로 실제 경량포장체의 거동특성을 추정하였다. FMA해석결과의 10배인 39.4kg(실제 하중35ton)의 횡하중를 가했을 경우 7.8mm(실제 거동 23.4mm)의 미세한 거동만 있었다. In general, Korean Lightweight Concrete used Heat insulating material for building and filler for civil construction, backfill material for tunnel, office floor fillers, lightweight blocks and so on. These expand the range of use ALC(autoclaved lightweight concrete) on the soft-ground at regular intervals during road construction by installing piles used as substrates for the process is under study. In this study, behavior characteristics on the soft-ground of pavement analysis was used to test the geo-Centrifuge. Prototype pavement reduced to 1/30 slab form of the composition as kaolinite model tests were conducted in the soft ground. Pile Arrangement (having 36 component pile with an array of <TEX>$3{\times}12$</TEX>) was used to group of piles. Tests of gravity 30 level the centrifugal force acting Light-weight pavement models. Based on the Prototype pavement of the behavior characteristics of pavement behavior characteristics were estimated. FMA analysis of the 10 times as big 39.4kg (actual load 35 ton) of the lateral load is applied to the case 7.8mm (actual behavior 23.4mm) behavior was fine.

Improved fire resistant performance of load bearing cold-formed steel interior and exterior wall systems

In order to improve the fire performance of load-bearing CFS wall systems for applications in mid-rise buildings, different panels and external insulation were examined in this paper. Experiments on six full-scale CFS wall specimens were performed in which the insulation material of aluminum silicate wool was located outside the CFS frame and sandwiched between two layers of boards on the fire side instead of being placed in the cavity. Five types of panels were involved in the experiments, including gypsum plasterboard, bolivian magnesium board, oriented standard boards (OSB), autoclaved lightweight concrete (ALC) boards and rock wool boards. The results showed a noticeable reduction of heat transfer to the surface of steel stud and a considerable improvement of fire performance of CFS walls by using aluminum silicate wool as external insulation. For CFS walls with aluminum silicate wool as external insulation on fire side, gypsum plasterboard as face layer and bolivian magnesium board as base layer on both sides, different load ratios may result in different failure modes, and the fire resistant time can be more than 150min when the load ratio was less than 0.65. It was also demonstrated that the fire performance of CFS wall systems lined with bolivian magnesium board or ALC boards were superior to those lined with gypsum plasterboard and OSB. Therefore, bolivian magnesium board may be recommended to replace gypsum plasterboards as the base layer and ALC board may be used to replace OSB as exterior wall panels of CFS wall systems for applications in mid-rise buildings.

Use of Sugarcane Bagasse Ash as Raw Material in Production of Autoclaved Lightweight Concrete

Sugarcane bagasse ash (ScBA) obtained as a byproduct of sugar processing may be used as a raw material for producing autoclaved lightweight concrete (ALC). We examined the chemical composition and physical properties of ScBA and determined that the material is not hazardous as defined by the Thai Ministry of Industry. The optimal production conditions for ScBA-containing ALC were a cement/sand ratio of 65/36, a water/total composition ratio of 0.24, and a curing time of 16 h. Maximum compressive strength was obtained in samples containing 20 wt% ScBA.

軽量気泡コンクリート材を利用したセシウムイオン交換材料の開発

軽量気泡コンクリート材を利用したセシウムイオン交換材料の開発

Shaking table test of steel frame with ALC external wall panels

A shaking table test of a steel frame with autoclaved lightweight concrete (ALC) external wall panels is described in this paper. The specimen is a two-story full-scale model filled with external vertical wall panels, external horizontal wall panels and internal vertical wall panels. The input wave of the shaking table was generated by the El-Centro 1940 earthquake spectrum. Based on the experimental results, the seismic behavior of ALC external walls and joints was analyzed, such as the failure modes of ALC external walls and joints and the effects of external walls on the dynamic response of steel frame. The test results show that there is no great crack or damage on the wall panels at the tenth seismic intensity because of the enough intensity. The comparison between the steel frame models with and without wall panels indicates that the contribution of external wall panels to the steel frame stiffness can reach up to 25% and the damping ratio can exceed 7%. The analysis results also show that the joints are stable enough to resist the seismic loads and can provide enough flexible deformation so that the wall panels can stand large structure deformation. The screws on band iron of openings are very easy to loosen. Therefore, the joints between the band iron and wall panels should be reinforced.

ALC(Autoclaved Lightweight Concrete) Hardness Prediction by Multiple Regression Analysis

ALC(Autoclaved Lightweight Concrete) Hardness Prediction by Multiple Regression Analysis

Experimental Research on Dynamics Characteristics and Damage of ALC Wallboard

The new building wall material ALC ( Autoclaved Lightweight Concrete) wallboard is solid composite sandwich panel. The existing standard requires that the ALC wallboard must meet resistance performance when it is laid into the wall. The evaluation index is determined and exists error. In order to guarantee the ALC board has better suitability，and make up the deficiency of the current specification. Through the impact resistance performance test of the ALC wallboard， study the dynamics characteristics under impact loading. Do some further analysis of the ALC wallboard dynamic characteristics damage problems through the change of frequency and the damping ratio. In turn， these changes can be the basis of structural damage evaluation. Laying a foundation for the ALC wallboard can better applied in practical projects.

Evaluation of Sealed Joint Performance for the Selection of Sealants Suitable for Use in Autoclaved Lightweight Concrete Panels

Abstract The strength of autoclaved lightweight concrete (ALC) is evidently lower than that of normal concrete. Therefore, when movement occurs at a sealed joint between ALC panels, the sealant is required to deform and remain intact without damaging the ALC substrate. However, there is currently not sufficient information to permit evaluation of the expected performance of sealants applied to ALC substrates. In this study, static and dynamic tests were carried out in order to obtain an index that could be used to select the modulus of a sealant that can be expected to provide long-term performance when applied to an ALC substrate. To develop this index, an initial study was carried out in order to clarify actual joint movement between ALC panels of buildings; the expansion and contraction at the joint were measured, and shear joint movement was calculated based on the expected story-to-story drift of an external wall due to earthquake loads. Thereafter, in a subsequent stage of the study, five types of two-component polyurethane sealant products, of different elastic modulus, were subjected to tensile and shear tests from which the relationship between stress and the type of joint fracture was determined. The results from these tests revealed that when the stress is greater than 0.6 to 0.7 N/mm2, the ALC substrate is more easily fractured than the sealant. In a final stage of the study, the cyclic fatigue resistance of the same two-component sealants was evaluated using tensile and shear fatigue tests. Results from the fatigue tests indicated that the high modulus sealants lost adhesion from the ALC substrate at an early stage in the test. As well, the fatigue resistance of test specimens with joints having three-sided adhesion was lower than that of specimens having normally configured joints with adhesion on two sides of the sealant. Therefore, on the basis of results derived from all the studies, it was determined that a suitable sealant for use on ALC substrates is a sealant having a low modulus that is applied in the normal fashion as a two-sided joint.

Durability of Acrylic Sealants Applied to Joints of Autoclaved Lightweight Concrete Walls: Evaluation of Exposure Testing

Abstract In Japan acrylic sealants are traditionally the sealant products of choice when specified for use between autoclaved lightweight concrete (ALC) panels. Although, in general terms, the mechanisms of the deterioration of acrylic sealants are well known its long-term durability to outdoor exposure has not, however, been fully investigated. The research described in this paper focuses on the change in the properties and deterioration of acrylic sealant products when exposed to outdoor testing. The two stage project consisted of (i) on-site investigations of deteriorated acrylic sealants that had been placed in external joints of ALC-clad buildings; and (ii) outdoor exposure testing of different types of acrylic sealant in three climate regions located in Japan. The results of the work from the first stage of the study revealed the following. Two-sided adhesion joint configurations installed in deep panel ALC cladding were more reliable than three-sided adhesion joints used for thin panel ALC cladding from the viewpoint of the durability of the sealed joint installed in actual buildings. Most fractures of the sealed joint could be characterized as failure in peel (or thin layer cohesive failures), in which the sealant ruptured at the interface with the ALC substrate to which it was applied. Additionally, in 47 of 62 locations surveyed, surface cracks were apparent on the coating that had been applied to protect the sealant. The second stage of the project focused on the degree of deterioration of coated and non-coated acrylic sealants subjected to outdoor exposure testing in a cold, a warm, and a subtropical climate. Results from this stage showed that aging of the sealant, as determined by the degree of surface cracking, expectedly depended on the local temperature and the respective degree of exposure to solar radiation. It was determined that the longer the exposure period, the lower the tensile performance of the acrylic sealants. The elongation of three-sided adhesive joint configurations after 5 years exposure testing decreased remarkably and their maximum elongation was less than 50 %. A significant number of sealed joints after 5 years ofexposure had ALC substrate failure.

멜라민 수지를 혼합한 ALC 소재의 특성에 관한 연구

ALC(Autoclaved Lightweight Concrete) is produced using quartz sand, lime and cement and water. And aluminum powder is used for blowing agent. ALC is manufactured by autoclave chamber under high-temperature and high-pressure. Generally, ALC is 1/4 levels lighter than concrete and mortar, because it has a lot of pores. So density of ALC is about 0.45~0.65 g/㎤. But, ALC has a weakness, typically low strength, with its porous structure. So, it is necessary to excellent strength properties for extensive apply of ALC materials in high porosity. In this study, melamine resin was used to improve the strength characteristics of ALC materials. We performed compressive and bending strength measurements. Compressive strength of ALC with 2% melamine resin increased 26.88% than ‘melamine-free’ ALC. Also we performed functionality evaluation such as thermal conductivity, sound absorption, and flame-resistance.

Experimental Research on Mechanical Properties of ALC Wallboard

The new building wall material solid composite sandwich panel consists of panel and inserted layer material-steel wire nets of composite light bar, and it is called ALC ( Autoclaved Lightweight Concrete) wallboard. The transportation, installation of ALC wallboard is required to meet certain strength requirement, and the wallboard can carry the aseismatic behavior and the bending capacity when it is laid into the wall. Therefore, in order to ensure the ALC wallboard can be better applied in practical engineering, the experimental research need to be done on the wallboard mechanical properties, such as impact resistance, hanging force, bending resistance, etc.

Study on Finite Element Model of Infilled Walls of Steel Frames

Autoclaved lightweight concrete (ALC) block infills are used widely for steel residential building system in China; the authors of this paper brought forward a kind of macro finite element (FE) model of ALC block infills of steel frames on the basis of experimental study. Furthermore the hysteresis model of the strut element of infill was established. At last the validity of the strut element was verified by comparison theory analysis results with experiment ones. The analysis method and theory of this paper can be applied to other kind of infills after being revised properly.

カーバイドかす-けい石-高炉スラグ系の発泡コンクリートの研究

カーバイドかす-けい石-高炉スラグ系の発泡コンクリートの研究

Experimental Study on Structural Performance of a Novel Integral Noise Barrier for Urban Rail Transit

A novel integral noise barrier (INB) composed of steel fiber reinforced cementitious composite (SFRCC) and basalt fiber reinforced plastic (BFRP) is put forward in this paper. Compared with traditional noise barrier, INB integrated sound-absorbing panel, H type steel, autoclaved lightweight concrete (ALC) bridge guardrail panel into a whole. The basic design idea and experimental method for INB are described. Based on the engineering demand for eastern extension project of the No.2 subway line of Nanjing, six specimens were cast and tested under simulated positive and negative loads. Under the design loads, six specimens did not crack and the lateral displacement on the top of the slab is less than H /250, where H is the height of INB. The experimental results show that INB can meet the design requirements of eastern extension engineering of the No.2 subway line of Nanjing.

Removal of mixed contaminants by Fe0-based biobarrier in flow-through columns using recycled waste materials

The present study investigated the reactivity and ability of permeable reactive barriers [zero-valent iron (ZVI)-barrier plus biobarrier) to remove various contaminants (Cd, As, Zn, Cu, Mn, Cr, NO3−, NH4+, and CODcr) from synthetic leachate. Two different reactive materials were used in this study, namely ZVI and autoclaved lightweight concrete (ALC). After 90 days of column operation, the contaminant profiles were determined along the length of the columns. The heavy metals were extensively removed in the bio-ALC and sequential barriers (ZVI plus bio-ALC), however the removal efficiencies for the heavy metals Zn and Cr in the ALC and bio-ALC barriers were comparatively low. Nitrate was completely removed (>99.9%) in the ALC, bio-ALC, and sequential barriers. More than 50% of the produced ammonium and organic materials were removed in the biologically reactive zone of the sequential barriers. The results of the present study suggest that sequential barriers are one of the best solutions for in situ remediation and that they can be applied to clean up the leachate released from landfills.

수열처리에 의한 폐병유리의 다공질 재료화

Porous materials were manufactured by hydrothermal treatment of waste bottle glass without foam agent. Factorial design was applied to analyze data by statistical methods and deal with the important factors for a process. The largest effect for porosity was for temperature of hydrothermal treatment. Amount of water and temperature-water interaction appeared to have little effect. The particle size of raw material was also identified as a major factor by one-way ANOVA and the porosity decreased as the size increased. The sintering temperature was not statistically significant for the porosity but was significant for the pore size. The porous material had compressive strength and thermal conductivity comparing with those of ALC (autoclaved lightweight concrete), although it has higher porosity than for ALC.

Interaction between cladding and structural frame observed in a full‐scale steel building test

AbstractInteraction between the external wall cladding and the seismic load resisting frame was examined in a full‐scale cyclic loading test of a three‐storey steel building structure. The building specimen had Autoclaved Lightweight Concrete (ALC, also designated as Autoclaved Aerated Concrete) panels installed and anchored to the structural frame as external wall cladding, using a standard Japanese method developed following the 1995 Kobe earthquake. ALC panelling is among the most widely used material for claddings in Japan. In the test, the ALC panel cladding contributed little to the stiffness and strength of the overall structure, even under a very large storey drift of 0.04 rad. No visible damage was noted in the ALC panels other than minor cracks and spalling of the bottom of the panels in the first storey. Consequently, in a Japanese steel building with properly installed ALC panel cladding, the structural frame is likely to be little affected by its cladding, and the ALC panels are capable of accommodating the maximum storey drift generally considered in structural design without sustaining discernible damage. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Development of a Method for CO2 Solidification of Glass and Concrete Waste Composites

Composite materials heve been prepared using a CO 2 solidification process from milling dust of autoclaved lightweight concrete (ALC; as matrix material), reinforced by addition of crushed glass (bottle) waste. The effect of varying glass collet size (0.08-5 mm) and glass volume (10-30%) on the fracture properties in the glass/ALC composite was examined by four point bending tests. For the glass/ALC composite cured under atmospheric conditions, we show, by conducting CO 2 solidification experiments at different CO 2 gas pressures (atmospheric, and 4-10 MPa), that the rate of reaction at the sample surface is faster under pressure, than under atmospheric conditions. At 4-10 MPa experimental conditions, a solidified 'reaction rim' is formed away from the sample surface characterized by the deposition of calcite, and a long internal fracture is created inside the sample, which reduces bending strength, although these characteristic features are not evident in samples cured at atmospheric conditions. Creation of the 'reaction rim' impedes further diffusion of CO 2 into the sample. Our results indicated that the CO 2 solidification of glass/ALC composite materials is best advanced under atmospheric conditions. The result also indicated that for <0.5 mm cullet size, the bending strength is enhanced, without being detrimental to fracture characteristics. However, increasing size of the crushed glass cullet (0.5 mm-5 mm) reduced the strength of the solidified composite. The interface between the ALC powder matrix and glass cutlet was weak, and a fraction glass cullets 0.08-0.5 mm size may be incorporated in the waste concrete matrix by as much as 30 vol%.

Development of a CO2 solidification method for recycling autoclaved lightweight concrete waste

This study aims to consolidate concrete waste using a CO 2 -solidification method. The CO 2 -solidification method was used to solidify milling dust of autoclaved lightweight concrete. The effects of water content, compaction pressure, curing time and reaction temperature on sample CO 2 content were investigated. The flexural strength of the solidified samples was determined by conducting four point bending tests.

Effects of processing and materials variations on mechanical properties of lightweight cement composites

Low-density/low-cost cement composites were fabricated. Carbon and alkali-resistant glass fibers were used to reinforce the matrix of industrial by-products; fly ash with silica fume, Portland cement, and calcium silicates were mixed in different proportions. The additional low density was obtained by adding perlite and foaming agents followed by hot water curing. The composites also were prepared by autoclave curing for comparison. The mechanical properties were improved by increasing the amount of silica fume, fly ash, and fibers. Both carbon fibers and alkali-resistant glass fibers were effective in reinforcing the matrices, but carbon fibers were superior to glass fibers. Fabrication techniques for producing lightweight cement composites that can substitute for autoclaved lightweight concrete was developed.