Recycledaggregateconcrete can acquire sufficient quality as structuralconcrete through material design and by using material that conforms to all related quality expectations. Recycledaggregateconcrete can also be designed by applying the value of a relative quality method. Therefore, it is considered applicable as aggregate for use in precastconcrete products. Up to 30% of natural crushed coarse aggregate can be replaced with coarse recycledaggregate without significantly affecting any of the mechanical properties of the concrete. As replacement amounts increase, drying, shrinkage and creep will increase and tensile strength and modulus of elasticity will decrease. However, compressive strength is not significantly affected. It is recommended that recycledaggregateconcrete be batched - pre-wetted and close to a saturated surface dry condition, like lightweight aggregates. To achieve the same workability, slump, and water-cement ratio, as in conventional concrete, the paste content or amount of water reducer generally has to be increased. Concrete with RCA can be transported, placed, and compacted in the same manner as conventional concrete ( Farmington Hills & Michigan,. 2001).
Sandwich panels have gained much attention as an effective structural element in engineering field. It has been used as load-bearing members in naval structures (Aicher and Hofflin, 1999). However, in the building and construction industry, most of the research published on sandwich panels are related to the study of the non-load bearing non-composite type of PCSP (Jokela et al., 1981, Olin et al., 1984, Hopp et al., 1986 and Bush, 1998). Section 2.2 in this Chapter will discuss in details the previous research that has been carried out on sandwich panels. The section will be narrowed down to several sub-sections which will discuss the various material used as the wyhte and core, the shear connectors influences on the behaviour of panels and the structuralbehaviour of panels under various loading that have been done on this type of panel especially in the context of their applications as load bearing walls.
ated from Scandinavia some thirty years ago. Nowadays, foam concrete technology has been widely used in construction industries. It is considered as an attractive material for its lightweight, better thermal properties and ease of construction. In the United States for instance, foamed concrete are used in an increasing number of applications. Cast-in-place foamed concrete are used for insulating roof-deck systems and for engineered fills for geotechnical applications while precast auto-claved products are widely used as load-bearing blocks, reinforced wall, roof and floor units and as non load-bearing cladding panels over a primary structural frame (Tonyan and Gibson, 1992).
Based on the previous research, it is proved that the research of PLFP is still limited and there are still many weaknesses that arise such as the research done by Lian . This study discussed about the ultimate limit behavior of reinforced concretesandwich panels under axial and eccentric loads. However, the numbers of the number of tested panels was small which is only 4 specimens; therefore, no generalized inferences could be drawn. The author will test sixteen (8 by 2) panel specimens with single shear connectors and the results will be compared with the results from similar panels with double shear truss connectors tested by previous researchers. By testing higher numbers of specimen more accurate results will be recorded from the average result obtained.
In Malaysia, industrialized building system (IBS) had started many decades ago but until now it is still experimenting with various prefabricated method. The governments of Malaysia also encourage the use of IBS and insist that the office building projects shall have at least 70% IBS component. To encounter demands from the growing population and migration of people to urban areas in this country, alternative construction method is required to provide fast and affordable quality housing and environmental efficient. One of the alternatives that already been studied is Precast Lightweight SandwichPanel. Before we can introduce new innovative construction method, the construction details are an important factor in building design. There has not been any study on Precast Lightweight Foamed ConcreteSandwichPanel (PLFP) connection.Connection is important to transfer loads and also for stability. With regard to the structuralbehaviour, the ability of the connection to transfer forces is the most essential property. Every aspect of the panel behavior must be analysied. This study will only focus on analyzing the performance of two small scale PLFP walls with U-bent bars connection under bending in term of load-displacement relationship, modes of failure and its ultimate load capacity when connected.
in term of carrying capacity. The experimental results show that, the wall panelusing CCwA show similar structuralbehaviour in term of ultimate load, displacement profile, and mode of failure. Based on the result, the reinforced concrete wall panel can sustain higher loading without remarkable failure especially when designed with double layer steel fabric, therefore wall panel also can be promoted as a load bearing unit. But for design purposes, the basic design criteria of short wall panel should follow all the parameter in this research such as dimension, grade of concrete, ratio and arrangement of steel fabric, and the range of ultimate load for the infill wall in construction application. When CCwA are accepted in present construction method, the cost and the environmental load in term of concrete waste would decrease compared to the construction without the use of recycled material especially for large-scale construction.
Mass migration of workforce population into the city and industrial centres has accelerated the demand of affordable and quality houses. High housing price has become a problem for low to medium income group especially in the cities. The increasing demand of affordable housing resulted in aggressive research on precastpanel system which includes solid and sandwich panels. Current research had also widen the scope of study on these panels using various materials such as normal and lightweight concrete as well as recycled waste material.
Jiang  carried out a direct shear push-out test to assess the performance of PrecastConcreteSandwichPanel (PCSP) with W-shaped Glass Fibre-reinforced Polymer shear connectors. The results indicate an elastic-brittle response caused by the pull-out of the connectors before the ultimate strength was reached. This indicates that the SGFRP material did not exhibit ductility behaviour. Many investigations have been carried out on the structural performance of PCSP with the alternative materials as summarized in Table 2(a)-(c). Despite the numerous investigations in this regard available in literature, no corresponding report yet regarding the thermal performance of the PCSP assemblies [40, 57]. Even though, report have shown that there is opposite behavior between the load capacity and thermal efficiency: increasing number of shear connectors increases the load capacity, but decreases thermal performance. However, Salmon  reported that the thermal conductivity of CFRP material is about 14% of steel conductivity, which encourages more research in using FRP as shear connector in PCSP system.
According to the study on the use of additives to enhance properties of preformed foamed concrete , it was found that the compressive strength of foam concrete decreased with a reduction of density but the compressive strength increased with the use of additives. This is due to the reduction of water content with the formation of less porous interfacial zone and provided a better interlocking between the paste and the aggregates. The results showed that the mixes with density 1300 and 1600 kg/m 3 are not suitable for structural purposes due to the low compressive strength obtained. The tensile strength and splitting of conventional mixes is higher than mixes with additives. For a given density, the sand content is lower in mixes with additives and degraded the shear capacity.
Tarek K. Hassan and Sami H. Rizkalla (2010), on the studies of “Analysis and design guidelines of precast, prestressed concrete, composite load-bearing sandwich wall panels reinforced with CFRP grid”, investigated three different precastconcretesandwich wall panels, reinforced with carbon-fiber-reinforced-polymer shear grid and constructed using two different types of foam, expanded polystyrene (EPS) and extruded polystyrene (XPS), were selected from the literature to validate the proposed approach. The results of the analysis indicated that the proposed approach is consistent with the actual behavior of the panels because the predicted strains compared well with the measured values at all load levels for the different panels. Besides that, the approach is beneficial to determine the degree of the composite interaction at different load levels for different panels at any given curvature. A simplified design chart is provided to calculate the nominal moment capacity of EPS or XPS wall panels as a function of the maximum shear force developed at the interface. A simplified design chart is proposed to calculate the nominal moment capacity of EPS and XPS foam-core panels at different degrees of composite interaction. The chart is valid only for the panel configuration, geometry, materials, and reinforcement used in the current study. However, it can easily be produced for different panels. The chart demonstrates the effect of composite interaction on the induced curvature.
This paper presents the overview on structuralbehaviour of precast lightweight concretesandwichpanel. In Malaysia, demand of affordable housing is increasing due to increasing number of population. Precastconcretesandwichpanel is an alternative solution to the conventional construction method due to its ease of construction. The question arises on how to develope a precastpanel which is lightweight but with higher strength to sustain the applied load. This paper aims to provide some findings from previous reseach in this field especially on the panel's structuralbehaviour subjected to eccentric load. It is hoped the overview on this subject matter could be used as guidance for future research on developing a lightweight sandwichpanel system in low to medium rise building construction.
Abstract. Recent years in Malaysia, precastconcretesandwichpanel gained its popularity in building industries due to its economic advantages, superior thermal and structural efficiency. This paper studied the structuralbehaviour of precast lightweight foamed concretesandwichpanel (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.
The availability of demolished concrete is increasing day by day and natural resources are depleting due to rapid development of construction industry. To meet the requirements of the construction industry there is a need to use recycled materials from C&D wastage as an aggregate in concrete. The current specifications in many parts of the world are not able to support and encourage the recycling of C and D waste. In recent past the usage of recycledconcreteaggregate has gained its peak to use as an aggregate in concrete. As the recycled the aggregate has more water absorption, and adhered mortar can be controlled by using pozzolanic materials such as met kaolin, silica fume, fly ash, slag, VCAS.
the table the NAC indicates the mix with natural aggregate and section is placed on torque arms to develop pure torsion moment. All precautionary measures are taken as the orientation of the centre of the beam exactly below the point of application of load. Maintaining initially the specimens horizontally without any rotation was taken during Load was applied at regular intervals of increments up to failure. For each increment of load, the beam was examined for cracks with magnifying glass and the deflections were noted. The load at which the first crack appeared was noted and also the propagation cracks were marked on the beams. The test was carried up to final failure and the final load is taken as ultimate load .Torsion test set up as shown in Figure 2(a) and tested beam can be viewed in
namely tie rod and dowel bars according to the technical requirements of the pavement. Aggregates are inert materials in concrete and considered as volumetric materials in concrete. The aggregates are occupied nearly 70 - 80% of the volume of concrete in which more than 50% is occupied by coarse aggregate (CA) . Coarse aggregates should be clean, hard, strong, non-porous pieces of crushed stone. The maximum size shall not exceed 25 mm. The steps are continuously taken by both central and state governments to improve the performance of existing pavements to meet future necessities and also proposed for new concrete road projects. Hence demand for CA portion is always exist. The researchers are taking steps to find alternate to natural CA by considering industrial byproduct [4-6], agricultural solid waste [3, 7] and building debris [8-9].The usage of RCA is a century old practice in conventional construction. However the research activities are performed to apply RCA in modern structuralconcrete. RCA is usually obtained from demolished concrete debris and covered old adhered mortar. The concrete debris are always to be processed for suitability in new concrete for getting superior quality concrete. The expected quality of RCA was obtained by removing unwanted old mortar portions stick in the debris before use as aggregate in new concrete . The water absorption and surface porosity of the RCA is higher than the conventional granite aggregate . Adding RCA in normal concrete is reported that the compressive strength is decreased up to 20% than the conventional CA concrete [12- 13]. The reductions in flexural strength and durability of RCA based concrete are noticed in various research findings [14-15]. The reports on increasing the carbonation depth and permeability are also presented by few results [15-16]. The review from the various studies reported that the reduction of mechanical and durability properties of RCA based concrete is attributed to the old mortar stick in the RCA. Various methods are used to eliminate stick mortar portion in RCA for improving the performance of RCA. Thermal treatment  and Acid treatment [17-18] are the examples of treatments to remove the old mortar portions in RCA. In this background, the present investigation is intended to evaluate appropriateness of RCA in PQC based on the compressive strength, flexural strength test and absorption test. RCA used in the study were processed in the laboratory by acid treatment.
In the pykno meter method, the prepared test portion was imme rsed in water pykno meter for the soaking per i- od of 24 hours to remove all entrapped air. According to BS EN 1097-6:2000 the pyknometer including aggre- gates and water must stand in the water bath and keep the test portion at a temperature of (22 ± 3) ˚C fo r (24 ± 0.5) hours . In this research, to get a h igher accuracy, the pykno meter and the re fill water was placed in a cu r- ing roo m, which was ma intained at a te mperature o f 20˚C for 24 hours (Figure 5 and Figure 6). Achiev ing sat- urated and surface-dried aggregates for particles size between 4 mm and 31.5 mm was exact ly the same as ag- gregate particles size between 31.5 mm and 63 mm. In o rder to assess whether the surface dry state has been achieved for aggregate particles between 0.063 mm and 4 mm, the metal cone mould test was applied.
Now days there are critical shortages of natural resources. A possible solution of these problems is to recycle demolished concrete and produce an alternative aggregate for structuralconcrete in this way. RCA reduces the impact on landfills decreases energy consumption and can provide cost savings. The use of recycled aggregates from construction and demolition wastes is showing prospective application in construction as alternative to natural aggregates. There are numerous skyscrapers, bridges, roads, underground tunnels, and deep water structures all over the world are constructed. To accommodate new structures many old buildings are demolished after their lie span and damaged condition caused by natural disaster. The demolition of structures is generating concrete rubbles and causing environmental problems due to unplanned disposal and scarcity of landfill sites. Nowadays this are used in construction industry.
In this research, these materials were used for experimental work. There are Ordinary Portland Cement (OPC), sand, natural gravel with maximum size 20mm and superplasticizer. RecycledAggregate (RA) was prepared by crushing the waste cubes which have been thrown away at the outside of Material Laboratory of Universiti Tun Hussein Onn Malaysia (UTHM). The waste cubes without considering the age were collected and broken into smaller pieces by using hammer. Then it is crushed by using a jaw crusher. Maximum size of RA that has been produced is 20 mm and minimum size is 5 mm. Then, the Micronised Biomass Silica (MBS) was prepared by burning the rice husk in rotary reactor furnace. This furnace has been located at Material Laboratory in Universiti Tun Hussein Onn Malaysia (UTHM) and enables to synthesis any biomass silica material with different regime of temperature. In order to obtain an amorphous material, the temperature for rotary furnace is fixed at 500 0 C. Off white amorphous material is obtained after one hour and about 50 gram of ash has been produced. Before that, rice husk is fed manually into the rotary furnace. Then, Jar Mill is used to produce finer biomass silica. After been grinding by Jar Mill for one hour, the particle size of MBS is reduced from 48 µm to 25.77 µm.
Two FEM models (2-D and 3-D models) were proposed to simulate the behaviour of PCSP as one-way and two-way acting slab respectively. The FEM proposed models were first validated by experimental data from Ellinna2. A parametric study was carried out to study the influence of shear the number of connectors on the ultimate strength and the compositeness of the PCSP working as slab. The investigation included a study of strain distribution, degree of composite action at ultimate and elastic stages of the PCSP, their ultimate strength capacities, load-deflection profiles, and load-stress relationships. A method for the determination of the interface shear force, required for the design of shear truss-shaped connectors was presented. Different aspect ratios of slabs were also chosen to study the effect of the placement and the orientation of shear connectors on the behaviour of PCSP.
Ideal level of compressive quality of 3D shapes, Optimum level of split rigidity and compressive quality of chambers, Optimum level of modulus of versatility of solid, Optimum level of loss of weight of 3D shapes in sturdiness test was found for the Concrete created from 15%, 20%, 25%, 30%, 35%, 40%, half, 60%, 70% substitution of characteristic fine total.