- Email: [email protected]
Ferrocement encased lightweight aerated concrete: A novel approach to produce sandwich composite
Materials Letters 61 (2007) 4035 – 4038 www.elsevier.com/locate/matlet
Ferrocement encased lightweight aerated concrete: A novel approach to produce sandwich composite Noor Ahmed Memon a,⁎, Salihuddin Radin Sumadi b,1 , Mahyuddin Ramli c,2 a b
Faculty of Civil Engineering, Universiti Teknologi Malaysia, Skudai, 81310, Johor, Malaysia Open Building Research Centre, Faculty of Civil Engineering, Universiti Teknologi, Malaysia c School of Housing and Planning, Universiti Sains, Malaysia Received 24 November 2006; accepted 6 January 2007 Available online 23 January 2007
Abstract This paper presents the experimental study to investigate the applicability of a novel technique to produce lightweight sandwich composite elements. Sandwich composite is fabricated by encasing lightweight aerated concrete as core with high performance ferrocement box as skin layer. The performance of the sandwich elements is investigated in terms of ultimate compressive strength, flexural strength, water absorption, overall unit weight and the failure mode. The results are compared with control specimens made solely of the aerated concrete. Results showed the remarkable enhancement in the compressive strength and flexural strength while the water absorption is reduced to fractions as compared to that of the control specimens. Overall unit weight of the sandwich composite elements falls in the range of the lightweight structural elements. The failure mode of the sandwich elements reveals the ductile and composite behavior thus transforming a pure brittle material (aerated concrete) into ductile composite material because of the ferrocement encasement. © 2007 Elsevier B.V. All rights reserved. Keywords: Sandwich; Composite; Ferrocement; Aerated concrete; Novel approach
1. Introduction Recently sandwich panels have gained much attention as an effective structural form in the building and construction industry. Sandwich panels have been used in the aerospace industry for many years and these are also being used as load bearing members in naval structures [1]. Sandwich panels offer high strength-to-weight ratio causing substantial reduction in the self-weight of the structures. The self-weight of the element with high density (weight) itself accounts for a major portion of the total load of the structure. Thus reduction in the self-weight of the structures by adopting an appropriate approach results in the reduction of element cross-section, size of foundation, cost and also the damages due to earthquake because the earthquake forces that will influence the buildings and other structures are ⁎ Corresponding author. Tel.: +60 17 7187483. E-mail addresses: [email protected] (N.A. Memon), [email protected] (S.R. Sumadi), [email protected] (M. Ramli). 1 Tel.: +60 12 7088363. 2 Tel.: +60 12 4209877. 0167-577X/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2007.01.039
proportional to the mass of the structure [2]. The use of sandwich panels with cores of lightweight concrete is spreading due to their manufacturing efficiency that leads to the industrialization of the building system [3]. Sandwich panels typically consist of two thin, high strength and density outside face sheets known as skin separated by a thick layer made of low strength and density material called as core [4]. Ferrocement laminated composite is also proved to be an effective material to produce skins of sandwich panels [5–9]. Ferrocement is a type of thin walled reinforced concrete that consists of cement mortar reinforced with closely spaced layers of continuous and relatively small wire mesh [10]. Its advantageous properties such as its versatility of application, strength, toughness, lightness, water tightness, durability, fire resistance and environmental stability can not be matched by another thin construction material [11,12]. The face sheets of a sandwich are usually connected by applying steel connectors/concrete webs, which pass from one face sheet to another face sheet through the core which interrupts the continuity of the insulation layer leading to the production of thermal bridges, thus causing the reduced effectiveness of the insulation layer. In some cases, the thermal performance
4036
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
Table 1 Details of specimens and test results Batch designation Batch description
Average compressive strength Average flexural strength Average water absorption (MPa) (MPa) (%)
AC 0L SCW1 SCW2 SCW3 SCW4 SSW1 SSW2 SSW3
7.4 15.3 15.9 16.9 17.8 18.1 20.3 21.7 22.4
Control specimens made of aerated concrete Sandwich specimens without mesh Sandwich specimens with one layer of chicken mesh Sandwich specimens with two layers of chicken mesh Sandwich specimens with three layers of chicken mesh Sandwich specimens with four layers of chicken mesh Sandwich specimens with one layer of square mesh Sandwich specimens with two layers of square mesh Sandwich specimens with three layers of square mesh
decreases by as much as 40% by the large quantities of heat conducted through the shear connectors and the concrete regions that penetrate the insulation [13]. On the other hand, the small area of the connectors may result in the buckling of the diagonals and also there might be separation of two face sheets near the upper part of the sandwich panel under compression [14,15]. In fact, the structural behavior of the sandwich panel depends greatly on the strength of and stiffness of the two face sheets, the way they are connected and partially on the strength of the core. Whereas, the thermal resistance of the core governs the insulation value of the panel. Limited research is reported in the literature to apply the alternative of the traditional method to produce the sandwich panels in order to improve the structural behavior such as composite behavior at failure and thermal efficiency [16]. The authors are aware of no systematic investigation reported yet to produce a sandwich panel with the novel technique; by encasing lightweight aerated concrete (which exhibits better compressive strength than that of the traditional materials used as core) with strong and stiff ferrocement box, where the wire mesh plays the role of the reinforcement in the face sheets and the uniformly distributed connectivity without passing through the core thereby avoiding the discontinuity of the insulating core. 2. Experimental 2.1. Materials Ordinary Portland Cement (OPC) in accordance with Type I in ASTMC 150-92 and Ground Granulated Blast Furnace Slag (GGBFS) confirming the specifications of ASTMC 989-89 were
1.46 2.45 2.92 3.54 3.98 4.7 3.29 5.64 7.2
16.72 4.15 3.94 3.74 3.86 3.91 3.79 3.31 3.6
used as binders. Local sand in compliance with ASTMC 33-92 was used for ferrocement box and for aerated concrete core it was passed from 600 μm sieve. Type F, high range water reducing admixture from group SNF in powder as per ASTMC 494-92 was used. To produce core, aluminum powder type Y250 was used as the gas-forming agent. Locally available square welded wire mesh, about 0.85 mm in diameter and 13 mm square grid and chicken (hexagonal) wire mesh with diameter of 0.5 mm and 18 × 14 mm wire spacing were applied in ferrocement box. Both the meshes used confirmed to the Ferrocement model code, IFS-2001. 2.2. Specimen preparation and testing In all nine batches of specimens are cast and tested including one batch of the control specimens cast solely from the aerated concrete. Each batch consists of cube and prism beam specimens of standard size. Table 1 presents the details of the specimen cast and tested. Non-autoclaved lightweight aerated concrete already produced [17] and modified subsequently was adopted to produce the control specimens and the core. Ferrocement box thickness was kept constant at 12 mm around the four sides of the entire specimens except control. Fig. 1 shows the dimensional view of the specimen's cross-section. Mortar mix of proportion 1:2 as recommended by Memon et al. [18,19] was applied to produce ferrocement box. A 50% partial replacement of cement with GGBFS is applied in both; aerated concrete and ferrocement mortar, since GGBFS is considered as a potential partial cement replacement from technical, economical and environmental considerations [20,21]. The sandwich specimens were cast in a two stage operation; casting of core on one day followed by the wire mesh wrapping and casting of ferrocement box on the next day. The specimens
Fig. 1. Dimensional view of the cross-section of the specimens. (a) Aerated concrete core, (b) sandwich without wire mesh and (c) sandwich with wire mesh.
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
4037
Fig. 2. Comparison of various properties of sandwich composite with control specimens. (a) Compressive strength, (b) flexural strength and (c) water absorption.
were cured in water for 28 days (age of testing). Compressive strength, flexural strength and water absorption tests were carried out according to ASTMC 109-92, ASTMC 78-84 and BS 1881: Part 122-1983 respectively. Entire specimens were weighed to determine the saturated unit weight at the time of testing. 3. Results and discussions A pronounced improvement in the performance of lightweight aerated concrete is obtained by encasing it in a ferrocement box to
produce a sandwich composite. Table 1 presents the average values of compressive strength, flexural strength and water absorption from the tests conducted and calculated accordingly. The enhancement in compressive strength as high as 203% of the control was achieved (SSW3), whereas, flexural strength also increased manifold (SSW3). The average value of water absorption drastically lowered to fractions (0.2) to that of the control. In fact water absorption is the measure of the porosity and permeability of the cement based composite which is considered as one of the major parameter in tropical areas like Malaysia. The performance of the comprising SSW specimens was better in all aspects than SCW specimens, which confirms to the results reported in the literature regarding the performance of
Fig. 3. Failure mode of various specimens after tests. (a) 0L after compression test, (b) SSW1 after compression test, (c) AC after flexural test and (d) SSW2 after flexural test.
4038
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
ferrocement elements. Fig. 2 depicts the comparison of various properties. During the compressive strength and flexural strength tests, the failure mode of the specimens was closely observed. Any sign of failure at the interface of aerated concrete and ferrocement box was not observed in any case, that confirms the composite behavior of sandwich. The control and sandwich without wire mesh showed apparent first crack at about 90–96% of their failure load followed by their sudden and complete collapse at failure load. The behavior of the sandwich specimens with wire mesh was ductile and the first crack appeared at 60% to 80% of their failure load depending upon the type and wire mesh layers. Although their shape was distorted at the failure load under compression, they were still intact as a unit. But, in flexure, after failure, the two portions of the sandwich prism beams were connected by means of a wire mesh. This is some sort of a sign of warning period prior to complete collapse of the structure, which imparts the application of sandwich elements especially in the earthquake borne areas. Fig. 3 presents the failure mode of some of the specimens tested. The average unit weight of the sandwich specimens at the time of testing was found to be about 1600 kg/m3 which is still 40% less than that of the normal concrete and places the sandwich composite within the range of lightweight materials.
4. Conclusions Based on the experimental study conducted and the discussion made, it can be concluded that, the encasement of lightweight non-autoclaved aerated concrete in ferrocement box is a novel and potential approach to produce lightweight sandwich composite. The sandwich elements produced are high performance in compressive strength, flexural strength and ductility whereas the water absorption is very low. These composites have the potential to be applied in earthquake borne areas and also may lead to the industrialization of the building system. References [1] H.M. Mahfuz, S. Islam, V.R. Mrinal, C. Aha, S. Jeelani, Response of sandwich composites with nanophased cores under flexural loading, Composites. Part B, Engineering 35 (2004) 543. [2] E. Yasar, C. Atis, A. Kilic, H. Gulshen, Strength properties of lightweight concrete made with blastic pumice and fly ash, Materials Letters 57 (2003) 2267. [3] N.A. Memon, S.R. Sumadi, M. Ramli, Ferrocement encased lightweight aerated concrete sandwich with variable core size and wire mesh layers,
[4]
[5] [6]
[7] [8] [9]
[10] [11]
[12] [13] [14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
8th International Symposium and Workshop on Ferrocement and Thin Reinforced Cement Composites, Bangkok, Thailand, 2006, p. 165. J. Hohe, L. Librescu, Y.O. Sang, Dynamic buckling of flat and curved sandwich panels with transversely compressible core, Composite Structures 74 (2006) 10. A. Nanni, W.F. Chang, Ferrocement sandwich panels under bending and edge-wise compression, Journal of Ferrocement 16 (1986) 129. M. Arafa, P.N. Balaguru, Flexural behaviour of high strength–high temperature laminate sandwich beams, 8th International Symposium and Workshop on Ferrocement and Thin Reinforced Cement Composites, Bangkok, Thailand, 2006, p. 189. M.K. El-Debs, E.F. Machado Jr., J.B. De Hanai, T. Tekeya, Ferrocement sandwich walls, Journal of Ferrocement 30 (2002) 45. M.A. Alkubaisy, M.Z. Jumaat, Punching shear strength of bolted ferrocement sandwich panels, Journal of Ferrocement 32 (2002) 1. P. Bhattacharyya, K.H. Tan, M.A. Mansur, Flexural moment capacity of ferrocement hollow sandwich panel system, Journal of Ferrocement 33 (2003) 183. ACI Committee 549, State-of-the-Art Report on Ferrocement, ACI, Farmington Hills, Michigan, 1997. N.A. Memon, S.R. Sumadi, Ferrocement: a versatile composite structural material, Mehran University Research Journal of Engineering and Technology 25 (2006) 9. A.E. Naaman, Ferrocement and Laminated Cementitious Composites, Techno press 3000, Ann Arbor, Michigan, 2000. W.C. McCal, Thermal properties of sandwich panels, Concrete International: Design & Construction 7 (1985) 34. A. Benayoune, A.A. Samad, A.A.A. Abang, D.N. Trikha, Response of precast reinforced composite sandwich panels to axial loading, Construction and Building Materials 21 (2007) 77. A. Benayoune, A.A. Samad, A.A.A. Abang, D.N. Trikha, Structural behavior of eccentrically loaded precast sandwich panels, Construction and Building Materials 20 (2006) 713. L. Byoung-jun, S. Pessiki, Thermal performance evaluation of precast concrete three-wythe sandwich panel, Energy and Buildings 38 (2006) 1006. N.A. Memon, S.R. Sumadi, M. Ramli, Lightweight aerated concrete incorporating various percentages of slag and PFA, Journal of Applied Sciences 6 (2006) 560. N.A. Memon, S.R. Sumadi, M. Ramli, Performance of High Workability SlagCement Mortar for Ferrocement, Building and environment, 2006 (online on sciencedirect.com since 14 September 2006). N.A. Memon, S.R. Sumadi, M. Ramli, Flow characteristics of mortar mix for ferrocement, Seminar Kebangsaan Penyelidikan Kejuruteraan Awam, Malaysia, 2005, p. 489. N.A. Memon, S.R. Sumadi, Study of ground granulated blast furnace slag as cementitious material in mortar mix, Mehran University Research Journal of Engineering and Technology 25 (2006) 89. ACI committee 226-87, Ground granulated blast-furnace slag as cementitious constituent in concrete, ACI Materials Journal (1987) 327.
Ferrocement encased lightweight aerated concrete: A novel approach to produce sandwich composite Noor Ahmed Memon a,⁎, Salihuddin Radin Sumadi b,1 , Mahyuddin Ramli c,2 a b
Faculty of Civil Engineering, Universiti Teknologi Malaysia, Skudai, 81310, Johor, Malaysia Open Building Research Centre, Faculty of Civil Engineering, Universiti Teknologi, Malaysia c School of Housing and Planning, Universiti Sains, Malaysia Received 24 November 2006; accepted 6 January 2007 Available online 23 January 2007
Abstract This paper presents the experimental study to investigate the applicability of a novel technique to produce lightweight sandwich composite elements. Sandwich composite is fabricated by encasing lightweight aerated concrete as core with high performance ferrocement box as skin layer. The performance of the sandwich elements is investigated in terms of ultimate compressive strength, flexural strength, water absorption, overall unit weight and the failure mode. The results are compared with control specimens made solely of the aerated concrete. Results showed the remarkable enhancement in the compressive strength and flexural strength while the water absorption is reduced to fractions as compared to that of the control specimens. Overall unit weight of the sandwich composite elements falls in the range of the lightweight structural elements. The failure mode of the sandwich elements reveals the ductile and composite behavior thus transforming a pure brittle material (aerated concrete) into ductile composite material because of the ferrocement encasement. © 2007 Elsevier B.V. All rights reserved. Keywords: Sandwich; Composite; Ferrocement; Aerated concrete; Novel approach
1. Introduction Recently sandwich panels have gained much attention as an effective structural form in the building and construction industry. Sandwich panels have been used in the aerospace industry for many years and these are also being used as load bearing members in naval structures [1]. Sandwich panels offer high strength-to-weight ratio causing substantial reduction in the self-weight of the structures. The self-weight of the element with high density (weight) itself accounts for a major portion of the total load of the structure. Thus reduction in the self-weight of the structures by adopting an appropriate approach results in the reduction of element cross-section, size of foundation, cost and also the damages due to earthquake because the earthquake forces that will influence the buildings and other structures are ⁎ Corresponding author. Tel.: +60 17 7187483. E-mail addresses: [email protected] (N.A. Memon), [email protected] (S.R. Sumadi), [email protected] (M. Ramli). 1 Tel.: +60 12 7088363. 2 Tel.: +60 12 4209877. 0167-577X/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2007.01.039
proportional to the mass of the structure [2]. The use of sandwich panels with cores of lightweight concrete is spreading due to their manufacturing efficiency that leads to the industrialization of the building system [3]. Sandwich panels typically consist of two thin, high strength and density outside face sheets known as skin separated by a thick layer made of low strength and density material called as core [4]. Ferrocement laminated composite is also proved to be an effective material to produce skins of sandwich panels [5–9]. Ferrocement is a type of thin walled reinforced concrete that consists of cement mortar reinforced with closely spaced layers of continuous and relatively small wire mesh [10]. Its advantageous properties such as its versatility of application, strength, toughness, lightness, water tightness, durability, fire resistance and environmental stability can not be matched by another thin construction material [11,12]. The face sheets of a sandwich are usually connected by applying steel connectors/concrete webs, which pass from one face sheet to another face sheet through the core which interrupts the continuity of the insulation layer leading to the production of thermal bridges, thus causing the reduced effectiveness of the insulation layer. In some cases, the thermal performance
4036
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
Table 1 Details of specimens and test results Batch designation Batch description
Average compressive strength Average flexural strength Average water absorption (MPa) (MPa) (%)
AC 0L SCW1 SCW2 SCW3 SCW4 SSW1 SSW2 SSW3
7.4 15.3 15.9 16.9 17.8 18.1 20.3 21.7 22.4
Control specimens made of aerated concrete Sandwich specimens without mesh Sandwich specimens with one layer of chicken mesh Sandwich specimens with two layers of chicken mesh Sandwich specimens with three layers of chicken mesh Sandwich specimens with four layers of chicken mesh Sandwich specimens with one layer of square mesh Sandwich specimens with two layers of square mesh Sandwich specimens with three layers of square mesh
decreases by as much as 40% by the large quantities of heat conducted through the shear connectors and the concrete regions that penetrate the insulation [13]. On the other hand, the small area of the connectors may result in the buckling of the diagonals and also there might be separation of two face sheets near the upper part of the sandwich panel under compression [14,15]. In fact, the structural behavior of the sandwich panel depends greatly on the strength of and stiffness of the two face sheets, the way they are connected and partially on the strength of the core. Whereas, the thermal resistance of the core governs the insulation value of the panel. Limited research is reported in the literature to apply the alternative of the traditional method to produce the sandwich panels in order to improve the structural behavior such as composite behavior at failure and thermal efficiency [16]. The authors are aware of no systematic investigation reported yet to produce a sandwich panel with the novel technique; by encasing lightweight aerated concrete (which exhibits better compressive strength than that of the traditional materials used as core) with strong and stiff ferrocement box, where the wire mesh plays the role of the reinforcement in the face sheets and the uniformly distributed connectivity without passing through the core thereby avoiding the discontinuity of the insulating core. 2. Experimental 2.1. Materials Ordinary Portland Cement (OPC) in accordance with Type I in ASTMC 150-92 and Ground Granulated Blast Furnace Slag (GGBFS) confirming the specifications of ASTMC 989-89 were
1.46 2.45 2.92 3.54 3.98 4.7 3.29 5.64 7.2
16.72 4.15 3.94 3.74 3.86 3.91 3.79 3.31 3.6
used as binders. Local sand in compliance with ASTMC 33-92 was used for ferrocement box and for aerated concrete core it was passed from 600 μm sieve. Type F, high range water reducing admixture from group SNF in powder as per ASTMC 494-92 was used. To produce core, aluminum powder type Y250 was used as the gas-forming agent. Locally available square welded wire mesh, about 0.85 mm in diameter and 13 mm square grid and chicken (hexagonal) wire mesh with diameter of 0.5 mm and 18 × 14 mm wire spacing were applied in ferrocement box. Both the meshes used confirmed to the Ferrocement model code, IFS-2001. 2.2. Specimen preparation and testing In all nine batches of specimens are cast and tested including one batch of the control specimens cast solely from the aerated concrete. Each batch consists of cube and prism beam specimens of standard size. Table 1 presents the details of the specimen cast and tested. Non-autoclaved lightweight aerated concrete already produced [17] and modified subsequently was adopted to produce the control specimens and the core. Ferrocement box thickness was kept constant at 12 mm around the four sides of the entire specimens except control. Fig. 1 shows the dimensional view of the specimen's cross-section. Mortar mix of proportion 1:2 as recommended by Memon et al. [18,19] was applied to produce ferrocement box. A 50% partial replacement of cement with GGBFS is applied in both; aerated concrete and ferrocement mortar, since GGBFS is considered as a potential partial cement replacement from technical, economical and environmental considerations [20,21]. The sandwich specimens were cast in a two stage operation; casting of core on one day followed by the wire mesh wrapping and casting of ferrocement box on the next day. The specimens
Fig. 1. Dimensional view of the cross-section of the specimens. (a) Aerated concrete core, (b) sandwich without wire mesh and (c) sandwich with wire mesh.
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
4037
Fig. 2. Comparison of various properties of sandwich composite with control specimens. (a) Compressive strength, (b) flexural strength and (c) water absorption.
were cured in water for 28 days (age of testing). Compressive strength, flexural strength and water absorption tests were carried out according to ASTMC 109-92, ASTMC 78-84 and BS 1881: Part 122-1983 respectively. Entire specimens were weighed to determine the saturated unit weight at the time of testing. 3. Results and discussions A pronounced improvement in the performance of lightweight aerated concrete is obtained by encasing it in a ferrocement box to
produce a sandwich composite. Table 1 presents the average values of compressive strength, flexural strength and water absorption from the tests conducted and calculated accordingly. The enhancement in compressive strength as high as 203% of the control was achieved (SSW3), whereas, flexural strength also increased manifold (SSW3). The average value of water absorption drastically lowered to fractions (0.2) to that of the control. In fact water absorption is the measure of the porosity and permeability of the cement based composite which is considered as one of the major parameter in tropical areas like Malaysia. The performance of the comprising SSW specimens was better in all aspects than SCW specimens, which confirms to the results reported in the literature regarding the performance of
Fig. 3. Failure mode of various specimens after tests. (a) 0L after compression test, (b) SSW1 after compression test, (c) AC after flexural test and (d) SSW2 after flexural test.
4038
N.A. Memon et al. / Materials Letters 61 (2007) 4035–4038
ferrocement elements. Fig. 2 depicts the comparison of various properties. During the compressive strength and flexural strength tests, the failure mode of the specimens was closely observed. Any sign of failure at the interface of aerated concrete and ferrocement box was not observed in any case, that confirms the composite behavior of sandwich. The control and sandwich without wire mesh showed apparent first crack at about 90–96% of their failure load followed by their sudden and complete collapse at failure load. The behavior of the sandwich specimens with wire mesh was ductile and the first crack appeared at 60% to 80% of their failure load depending upon the type and wire mesh layers. Although their shape was distorted at the failure load under compression, they were still intact as a unit. But, in flexure, after failure, the two portions of the sandwich prism beams were connected by means of a wire mesh. This is some sort of a sign of warning period prior to complete collapse of the structure, which imparts the application of sandwich elements especially in the earthquake borne areas. Fig. 3 presents the failure mode of some of the specimens tested. The average unit weight of the sandwich specimens at the time of testing was found to be about 1600 kg/m3 which is still 40% less than that of the normal concrete and places the sandwich composite within the range of lightweight materials.
4. Conclusions Based on the experimental study conducted and the discussion made, it can be concluded that, the encasement of lightweight non-autoclaved aerated concrete in ferrocement box is a novel and potential approach to produce lightweight sandwich composite. The sandwich elements produced are high performance in compressive strength, flexural strength and ductility whereas the water absorption is very low. These composites have the potential to be applied in earthquake borne areas and also may lead to the industrialization of the building system. References [1] H.M. Mahfuz, S. Islam, V.R. Mrinal, C. Aha, S. Jeelani, Response of sandwich composites with nanophased cores under flexural loading, Composites. Part B, Engineering 35 (2004) 543. [2] E. Yasar, C. Atis, A. Kilic, H. Gulshen, Strength properties of lightweight concrete made with blastic pumice and fly ash, Materials Letters 57 (2003) 2267. [3] N.A. Memon, S.R. Sumadi, M. Ramli, Ferrocement encased lightweight aerated concrete sandwich with variable core size and wire mesh layers,
[4]
[5] [6]
[7] [8] [9]
[10] [11]
[12] [13] [14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
8th International Symposium and Workshop on Ferrocement and Thin Reinforced Cement Composites, Bangkok, Thailand, 2006, p. 165. J. Hohe, L. Librescu, Y.O. Sang, Dynamic buckling of flat and curved sandwich panels with transversely compressible core, Composite Structures 74 (2006) 10. A. Nanni, W.F. Chang, Ferrocement sandwich panels under bending and edge-wise compression, Journal of Ferrocement 16 (1986) 129. M. Arafa, P.N. Balaguru, Flexural behaviour of high strength–high temperature laminate sandwich beams, 8th International Symposium and Workshop on Ferrocement and Thin Reinforced Cement Composites, Bangkok, Thailand, 2006, p. 189. M.K. El-Debs, E.F. Machado Jr., J.B. De Hanai, T. Tekeya, Ferrocement sandwich walls, Journal of Ferrocement 30 (2002) 45. M.A. Alkubaisy, M.Z. Jumaat, Punching shear strength of bolted ferrocement sandwich panels, Journal of Ferrocement 32 (2002) 1. P. Bhattacharyya, K.H. Tan, M.A. Mansur, Flexural moment capacity of ferrocement hollow sandwich panel system, Journal of Ferrocement 33 (2003) 183. ACI Committee 549, State-of-the-Art Report on Ferrocement, ACI, Farmington Hills, Michigan, 1997. N.A. Memon, S.R. Sumadi, Ferrocement: a versatile composite structural material, Mehran University Research Journal of Engineering and Technology 25 (2006) 9. A.E. Naaman, Ferrocement and Laminated Cementitious Composites, Techno press 3000, Ann Arbor, Michigan, 2000. W.C. McCal, Thermal properties of sandwich panels, Concrete International: Design & Construction 7 (1985) 34. A. Benayoune, A.A. Samad, A.A.A. Abang, D.N. Trikha, Response of precast reinforced composite sandwich panels to axial loading, Construction and Building Materials 21 (2007) 77. A. Benayoune, A.A. Samad, A.A.A. Abang, D.N. Trikha, Structural behavior of eccentrically loaded precast sandwich panels, Construction and Building Materials 20 (2006) 713. L. Byoung-jun, S. Pessiki, Thermal performance evaluation of precast concrete three-wythe sandwich panel, Energy and Buildings 38 (2006) 1006. N.A. Memon, S.R. Sumadi, M. Ramli, Lightweight aerated concrete incorporating various percentages of slag and PFA, Journal of Applied Sciences 6 (2006) 560. N.A. Memon, S.R. Sumadi, M. Ramli, Performance of High Workability SlagCement Mortar for Ferrocement, Building and environment, 2006 (online on sciencedirect.com since 14 September 2006). N.A. Memon, S.R. Sumadi, M. Ramli, Flow characteristics of mortar mix for ferrocement, Seminar Kebangsaan Penyelidikan Kejuruteraan Awam, Malaysia, 2005, p. 489. N.A. Memon, S.R. Sumadi, Study of ground granulated blast furnace slag as cementitious material in mortar mix, Mehran University Research Journal of Engineering and Technology 25 (2006) 89. ACI committee 226-87, Ground granulated blast-furnace slag as cementitious constituent in concrete, ACI Materials Journal (1987) 327.