Abstract. Precastlightweight concrete slab is first fabricated in workshop or industrial before construction and then transported to site and installed by skilled labour. It can reduce construction time by minimizing user delay and time for cast-in-situ to increase workability and efficiency. is environmental friendly and helps in resource reduction. Although the foamed concrete has low compressive strength compared to normal weight concrete but it has excellent thermal insulation and sound absorption. It is environmental friendly and helps in resource reduction. To determine the material properties of foamed concrete, nine cubes and six cylindrical specimens were fabricated and the results were recorded. In this study, structural behaviour of precastlightweight panel (PLP) with dry density of 1800 kg/m 3 was tested under flexural load. The results were recorded and analysed in terms of ultimate load, crack pattern, load-deflection profiles and strain distribution. Linear Voltage Displacement Transducers (LVDT) and strain gauges were used to determine the deflection and strain distribution of PLP. The theoretical and experimental ultimate load of PLP was analysed and recorded to be 70 and 62 kN respectively, having a difference of 12.9%. Based on the results, it can be observed that PLP can resist the adequate loading. Thus, it can be used in precast industry for construction purposes.
The development of precast sandwich concrete has gained acceptance worldwide in conjunction with the Industrial Building System (IBS). The advancement and improvement of using wall panel has gone through a lot of achievements through the decade. The usage of precastlightweight sandwich panel has become the alternative to conventional construction using brick wall. The usage of this panel system contributes to a sustainable and environmental friendly construction. This paper presents an overview of the latest development in precast concrete sandwich panel as an IBS. The purpose of this report is to provide comprehensive information on latest research development of sandwich panel for building construction purposes. The information on sandwich panel‟s composition, material, properties, strength, availability, and its usage as structural element are reported. An innovative concept used in the design of these systems and the use of lightweight materials is also discussed.
Abstract. Recent years in Malaysia, precast concrete sandwich panel gained its popularity in building industries due to its economic advantages, superior thermal and structural efficiency. This paper studied the structural behaviour of precastlightweight foamed concrete sandwich panel (PLFP) with double shear truss connectors under eccentric load. Preliminary results were analysed and studied to obtain the ultimate load carrying capacity, load-deflection profiles and strain distribution across the panel thickness at mid depth. The achieved ultimate load carrying capacity of PLFP due to eccentric load from the experimental work was compared with values calculated from classical formulas (if it is more than 1 comparison) developed by previous researchers. Preliminary results showed that, the use of double shear truss connectors in PLFP was able to improve its ultimate load carrying capacity to sustain eccentric load and achieve certain compositeness reaction in between the wythes.
From the previous research, it is noticed that most of the panels developed were made of conventional concrete. Any structural element made from conventional concrete are normally strong but has lower strength over weight ratio. Therefore, further research on this type of panel with lightweight materials is very much in need. The research investigates the structural behavior of PrecastLightweight Foamed Concrete Sandwich Panel, PLFP, with double shear truss connectors under axial Load and two Connected PLFP panels under four point bending load. The aim of this research is to achieve the intended strength for use in low to medium rise building. Considering its lightweight and precast construction method, it is feasible to be developed further as a competitive IBS building system. The result from this research could be used as a guideline for future research to develop PLFP panel as a walling unit in the industry and the future development of PLFP as a structural material.
The conventional concrete is strong but high in selfweight. This factor effects the ease of construction which will lengthen the construction period. More construction workers are needed to accellerate the progress of the construction work. Due to increase of workers, the cost will also increase. The traditional labor-intensive practices which includes the three problems;namely, dirty, difficult and dangerous have always been associated with the construction industry. The construction industry suffers from low productivity, safety and quality control due to this syndrome. Therefore, the use of precastlightweight concrete to substitude the conventional concrete has become vital because of its advantages and environmental friendly.
4. To develop a semi-empirical expression to estimate the load carrying quire this country to look for alternative construction method to provide fast and affordable quality housing to its citizens. Efforts have been taken to move from the traditional building construction technique to a more innovative construction method to meet these demands. As a part of this effort, an extensive investigation to develope a PrecastLightweight Foamed Concrete Sandwich Panel or PLFP as a load bearing wall system is undertaken.
From previous research, it is noticed that most of the panels developed are made of conventional concrete which made up the outer skins. This does not contribute to increase of strength over weight ratio. Therefore, further research on this type of panel with lightweight materials is very much in need. The author will investigate the structural behavior of PrecastLightweight Foamed Concrete Sandwich Panel, PLFP, with double shear truss connectors under axial Load. The aim of this research is to achieve the intended strength for use in low to medium rise building. Considering its lightweight and precast construction method, it is feasible to be developed further as a competitive IBS building system.
(12) The latest researcher who studied the behaviour of precastlightweight foam concrete panel with single shear connector was Mohamad . Based on the study, an empirical expression for the ultimate load capacity was suggested. The proposed equation was modified from the previous research equations, ACI318  and BS 8110  by incorporating the contribution of the steel area and by introducing the eccentricity of � − . The multiplying factor for steel is reduced to 0.6 because steel’s contribution on the strength of panel is generally very small. The eccentricity is included in the equation due to imperfection during testing. The proposed equation is as below:
This study is aimed to provide information about the structural behaviour of PLFP with shear connectors. It is able to get a clear and deeper insight on the structural behaviour and failure mechanisms of the PLFP with single and double shear truss connectors under axial and push off loading. The results from this study are very important to assist the design of the PLFP to be used as a precast wall system especially the ultimate load carrying capacity and failure mechanism. An empirical equation is proposed in this study which is able to predict the ultimate load carrying capacity of PLFP under axial loading. The equation can be used to predict the maximum load of sandwich in non-linear behaviour after the service load.
Precast concrete sandwich panel or PCSP technology has advanced gradually over the past four decades in North America. The first prefabricated panels were of non-composite type and consisted of a thick structural wythe, a layer of insulation and a non-structural wythe (Seeber et al., 1997). PCSP have all of the desirable characteristics of a normal precast concrete panel such as durability, economy, fire resistance, large vertical spaces between supports, and potential usage as shear walls, bearing walls, and retaining walls. On top of that, PCSP can be relocated to accommodate building expansion. The hard surface on both the inside and outside of the panel provides resistance to damage and a finished product requiring no further treatment.
Precastlightweight foamed concrete sandwich panel is an alternative sandwich structure component that can meet the rapid housing demand in Malaysia. It consists of lightweight foamed concrete as the wythes layer and polystyrene core as the insulation layer. Shear connector are embedded across each layer to allow load shearing between wythes. Stiffness of the shear connectors and its ability to transfer load between wythes will determine the strength and stability of PLFP. Figure 2.2 shows the PLFP layout with single shear connector.
Several previous studies have also been conducted on steel bar as shear connectors but the numbers are limited. Benayoune et al. and Mohamad both studied the performance of steel shear connec- tors in precast sandwich wall system [29,30]. Benayoune et al. studied the structural behavior of precast concrete sandwich walls (PCSP) using conventional concrete as the wythe and polystyrene as the insulation layer while Mohamad studied the performance of precastlightweight foamed concrete sandwich walls (PLFP) using foamed concrete as the outer wythe and polystyrene as the insulation layer. In both studies, single steel shear connector (SSC) was used to strengthen the wall. Results from both studies showed that the ultimate strength achieved in PLFP was slightly lower than the ultimate load achieved in the PCSP but both sand- wich walls behaved in a partially composite manner. Slenderness ratio (H/t) was proven to have significant effects on the structural behavior of both walls. These studies have shown that sandwich wall from lightweight foamed concrete strengthened with efficient steel shear connector system has potential to be developed as a load bearing wall.
Aerated concrete is a lightweight, cellular material consisting of cement or lime and sand or other silicious material. It is made by either a physical or a chemical process during which either air or gas is introduced into a slurry, which generally contains no coarse material. Usual methods of aeration are by mixing in stabilized foam or by whipping air in with the aid of an air entraining agent. Aerated concrete has many advantages when compared with conventional concrete such as reduced dead load, lower coefficient of thermal expansion, good sound insulation as a result of air voids with in aerated concrete. In this study aluminium powder is used as the air entraining agent. This study aims to develop an aerated concrete with partial replacement of cement with fly ash and fine aggregate with rubber powder. Rubber powder used for this study is made from used tyres of vehicles. The work also includes the evaluation of mechanical properties of aerated concrete.
Technological advances changes the way of doing business in areas of the construction industry. Companies that still practice traditional methods in construction process don’t have the chance to get success in today’s competitive business environment. Adoption to the new trends and methods in technology is a necessity for the success of companies and the development of the industry. Precast concrete solutions can help to reduce the waste generated on site by up to 50% of a construction building compared to Cast-in- situ method. The design system which can be implemented by the manufacturing company is tri- dimensional modelling software that helps maintain the interface between the different construction elements. A further study on the software will help designers to better understand the design and specification of elements that cannot be manufactured or transported. Hence the waste reduction technique needs to be implied as prior to manufacturing and construction on site as possible  G.Arsnal, Turkey. Web-based quality management system can offer many advantages in the quality control process of precast concrete. The program’s aim is to obtain the information during production, transportation and erection stages and checking the quality standards and specifications of precast concrete which can control the properties, dimensions of the products and irregularities at the production stage. The transportation and erection stages are also preceded by this program. This helps in understanding the precast stages from production, transportation to erection. It
Analytical modeling of hollow core concrete masonry unit wall was done by using the software NASTRAN NX9. Three precast unit were modelled and wall was created by arranging those units one above another. The precast units were joined by reinforced concrete of grade M20 and one 8 mm HYSD bar was used. The reinforced concrete was filled in three holes of precast units, one at the middle and two at the ends. Material properties given to the different components of wall were shown in table 2. Hexahedron meshing was used.Load was given at the top region of wall. Load increment was taken as 1kN.
We have proposed a lightweight authentication framework called Video Streaming Authentication (VSA ). The lightweight authentication considers the verification and transmission of video streaming on lossy network and reducing verification overhead on lossless networks. So VSA provides both high verification probability and low authentication overhead in continuous video streaming environment. Our proposed lightweight Layered authentication is an identity and access management process that is implemented in the secure video streaming, which has a high exposure to risk and fraud. This is typically used to authenticate individuals before granting access to a particular system and requires more evidences and verifications of identity for authentication. The layered lightweight authentication-based video streaming requires two or more identity credentials for authentication.
The key technology of light weight secure protocol is that it occupied small space, computes fast and has high security. In the light weight authentication protocol, only dozen of bytes is used to finish the authentication of mobile terminal. The light weight signature and encryption protocol only use one key mechanism and a symme- tric key to realize the signature and encryption process, the complexity is reduced. Due to the lightweight secure protocol is totally based on symmetric key mechanism, the computation speed is improved. At the same time, because the secure UIM chip’s nature, the security is improved too.
Lightweight concrete (LWC)mostly used in production of lightweight blocks or bricks and used in partitions of buildings , houses and framed structures , because of its low density that leads to reduce the total weight (dead weight) of building and hence low cost for structure. The use of steel fibers in concrete is very important to increase ductility [ 1 ] and also all mechanical properties , like compressive , tensile , and flexural strength the fiber reinforced concrete applications is very wide , it used in bridges ,precast products, structures in seismic regions, high loaded members and in concrete that needs to prevent cracks [ 2] , using fiber reinforced concrete leads to increase toughness , ductility and durability of concrete [ 3 ].The need to improve the mechanical properties of LWC is important so that it may be used as structural members. This investigation show how can steel fibers take rule to improve two types of lightweight concrete the first is no fine concrete which is concrete without fine aggregate or sand , and the second type is lightweight aggregate concrete which using crushed thermo -stone as lightweight aggregates, the no-fines concrete used in study with density of 1787 kg/m3 , and for LWCA the density was 1550 kg/m3.
Precast structure is analysed as moment resisting frame in Etabs 2013. Structural elements like shear walls, core walls, slab, and beams are only considered and if any balcony exists their loads are considered in the frame analysis. Frame with G+5 storeys with head room for lift allowance is modelled. Since precast structures have minimum C35 grade concrete, hence all the material properties and sections are assigned to the structure. Slabs are considered as membrane elements in Etabs; that transfer load via one-way slab action. Figure 1 show the Etabs model the precast structure under study and the section and material properties are given in Table 1 to 3. Assumptions considered in the analyzing of building are; a) Shear walls are considered instead of columns with 1.8x0.2 m throughout the building b) The building is suitably located in warangal; loads for wind, quake and geotechnical aspects are related to it c) Building has heavy loads at the ground floor hence foundation and podium slab are made cast in-situ d) Since water table is at 2 m below the earth raft foundation is preferred for the building e) Using space for residential room's