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A mixture of thermal, porosity and compressive strength properties of lime based materials were determined after adding different percentages of nanomaterials to enhance performance (nSiO2, nClay and nZnO). Specimens were formulated for use in the design of a five layer energy efficient wall. Materials consisted of lime nanocomposites (used as ‘Renders’, properties determined were thermal conductivity () and porosity) and lime/hemp shiv nanocomposites for thermal isolation ('Insulators', ). A lime/hemp fibre nanocomposite, with PVAc glue for strength, was developed as a load bearing material ('Core', , strength). A solvent exchange method for drying the specimens was applied as soon as practically possible to investigate if rapid drying could be considered without adverse effects. Results showed that the maximum 28 day decrease in for the Render was by using 4% nZnO, being -18% compared to the control sample. The same render also exhibited the lowest density. For the Insulator, λ was -31% when also using 4% nZnO in comparison to the nanofree specimen. Strength of the Core exceeded 10 MPa, much greater than the minimum load bearing requirement. The paper concludes by comparing the U value of a wall utilising these findings to those from an existing lime/hemp design.

This study presents a detailed analysis of the lateral forces generated as a result of vertically applied loads to recycled plastic drainage kerbs. These kerbs are a relatively new addition to road infrastructure projects. When concrete is used to form road drainage kerbs, its deformation is minimum when stressed under heavy axle loads. Although recycled plastic kerbs are more environmentally friendly as a construction product, they are less stiff than concrete and tend to deform more under loading leading to a bursting type, lateral force being applied to the haunch materials, the magnitude of which is unknown. A method is proposed for establishing the distribution of these lateral forces resulting from deformation under laboratory test conditions. A load of 400 kN is applied onto a total of six typical kerbs in the laboratory in accordance with the test standard. The drainage kerbs are surrounded with 150 mm of concrete to the front and rear haunch and underneath as is normal during installation. The lateral forces exerted on the concrete surround as a result of deformation of the plastic kerbs are determined via a strain measuring device. Analysis of the test data allows the magnitude of the lateral forces to the surrounding media to be determined and, thereby, ensuring the haunch materials are not over-stressed as a result. The proposed test methodology and subsequent analysis allows for an important laboratory-based assessment of any typical recycled plastic drainage kerbs to be conducted to ensure they are fit-for-purpose in the field.

This paper investigates the performance of pre‐tensioned tendons deliberately exposed to higher than normal impressed current cathodic protection (ICCP) to replicate accidental over‐polarisation. Plain ungalvanised tendons, 5.4 mm O, were pre‐stressed in moulds and cast in mortar. Two levels of pre‐tensioning were investigated, low (~30% ultimate tensile strength [UTS]) and high level (~80% UTS). Three different degrees of corrosion with target losses of cross‐sectional area of 0%–1%, 2%–4% and 4%–7%, respectively, were employed to replicate in situ conditions. ICCP was applied to the tendons at two levels of polarisation, normal protection (ICCP‐N) in the range of −650 to −750 mV and overprotection (ICCP‐O) ranging between −850 and −1300 mV, both versus Ag/AgCI/0.5‐M KCI for an extended period. After ICCP, the tendons were removed from the mortar and slow strain tensile tests were conducted. The results show that ICCP at both normal and overprotection had no significant influence on the elastic modulus, yield, 0.2% proof stress and ultimate strength of the tested tendons. Although ductility was reduced, fracture occurred after reaching the ultimate strength.

Circular concrete tanks and containment\ud bunds constructed by the pre-load method involves\ud pre-stressing the concrete by repeatedly wrapping\ud layers of highly tensioned tendons. Each layer is\ud covered with gunite. Corrosion may lead to rupture\ud and an explosive type failure is avoided if the gunite is\ud able to absorb the transfer stress. Zinc galvanizing is\ud used to increase the tendons resistance to corrosion but\ud its smoothness can influence bond characteristics, as\ud can corrosion if extensive. This paper investigates the\ud pre-stress transfer of ruptured pre-load tendons in\ud gunite, both in the uncorroded and corroded state.\ud Laboratory testing was conducted where tendons were\ud pre-loaded in custom-built stressing moulds (to\ud 1000 MPa) and simulated gunite applied. Different\ud degrees of accelerated corrosion were applied to the\ud tendons (0–10%). The bond stress at transfer was\ud determined by measuring the contraction of the tendon\ud during release of the pre-stress (replicating a broken\ud tendon). The results show that a low bond stress was\ud found either as a result of the smooth zinc coating\ud (uncorroded tendons) or due to higher levels of\ud corrosion. These results were compared to design\ud equations from Eurocode 2 and recommendations are\ud made for reducing the bond coefficient gp1, the\ud coefficient that takes into account the type of tendon\ud and the bond situation. Analysis is subsequently\ud conducted to determine the transfer stress in the gunite\ud by modelling single and double tendon ruptures and\ud establishing the magnitude of compressive stress\ud which, if excessive, may lead to an explosive type\ud failure of the gunite.

Composite insulation panels (CIPs) currently used in building facades require significant design changes e.g. increased thickness to realise higher thermal and sound insulation performance. This study deals with the manufacturing and characterisation of smart facade panels for achieving higher thermal and sound insulation dual characteristics in one panel without a significant increase in thickness. Prototype panels were manufactured using vacuum insulation core (VIC) combined with mass loaded vinyl (MLV) layers. Thermal transmission and weighted sound reduction index (R_w) was experimentally measured in the laboratory. The results were compared with a control panel made with extruded polystyrene (XPS) core. The VIC panel showed a 51% improvement in the centre of panel U-value compared to control XPS core panel of the same thickness. Integrating the two MLV layers inside of aluminium skins either side of the vacuum insulation panel led to 3dB improvement in R_w from 32 dB to 35 dB which could be further improved by optimising the MLV layer positioning in the CIP and better bonding between the MLV and the vacuum insulation panel. This shows that vacuum insulation core panels combined with MLV offers a solution to achieve smart building facade with excellent thermal and sound insulation performance.

The influence of the long term effects of impressed current cathodic protection (ICCP) on the bond strength is investigated. A total of 16 pull-out specimens were divided into four series and the steel bars pre-corroded to target degrees of 0 % (control), 1 %, 2 % and 5 % weight loss. Four levels of ICCP current density ranging from approximately 0 (control) to over 1000 µA/cm2 were applied to each series. These are considerably higher than the levels typically used in practice, which rarely exceed 2 µA/cm2, but were used to replicate long term application within a reasonable timescale. Following pull-out tests, the values of bond load were determined. The analysis accounts for the accelerated ICCP by relating the total charge to the steel reinforcement in coulombs (current x time) to the bond values and migration of chloride ions. The results show that although some loss in bond is evident from the ICCP, an optimised current density can be applied to a real structure without affecting the as-designed bond strength in the long term e.g. ≤ 0.65 µA/cm2 for an ICCP duration of 70 years. Application of the same current density reduces the chloride concentration from around the steel irrespective of the degree of corrosion.

The dual function of a carbon fibre reinforced polymer (CFRP) rod working as the near-surface mounted (NSM) strengthening and impressed current cathodic protection (ICCP) anode for corroded reinforced concrete structures has been proposed and researched. In this paper, a CFRP rod was used for both flexural strengthening of pre-corroded reinforced concrete beams and in a dual functional capacity as an ICCP anode. After a period of ICCP operation at high current density, the beams were subjected to flexural testing to determine the load–deflection relationships. The potential decays of the steel met recognised ICCP standards, and the CFRP remained effective in strengthening the corroded reinforced concrete beams. The bonding at the CFRP rod anode and concrete interface was improved by using a combination of geopolymer and epoxy resin; therefore, the ultimate strength of a dual function CFRP rod with combination of bonding medium (geopolymer and epoxy) increased significantly.

Circular concrete tanks and containment bunds constructed by the pre-load method involves pre-stressing the concrete by repeatedly wrapping layers of highly tensioned tendons. Each layer is covered with gunite. Corrosion may lead to rupture and an explosive type failure is avoided if the gunite is able to absorb the transfer stress. Zinc galvanizing is used to increase the tendons resistance to corrosion but its smoothness can influence bond characteristics, as can corrosion if extensive. This paper investigates the pre-stress transfer of ruptured pre-load tendons in gunite, both in the uncorroded and corroded state. Laboratory testing was conducted where tendons were pre-loaded in custom-built stressing moulds (to 1000 MPa) and simulated gunite applied. Different degrees of accelerated corrosion were applied to the tendons (0–10%). The bond stress at transfer was determined by measuring the contraction of the tendon during release of the pre-stress (replicating a broken tendon). The results show that a low bond stress was found either as a result of the smooth zinc coating (uncorroded tendons) or due to higher levels of corrosion. These results were compared to design equations from Eurocode 2 and recommendations are made for reducing the bond coefficient $$ \upeta_{p1} $$ , the coefficient that takes into account the type of tendon and the bond situation. Analysis is subsequently conducted to determine the transfer stress in the gunite by modelling single and double tendon ruptures and establishing the magnitude of compressive stress which, if excessive, may lead to an explosive type failure of the gunite.

This paper, based on UK practice, sets out a series of examples of previous studies of low energy housing and housing modernisation which illustrate the main approaches to studying housing and energy issues. The four approaches exemplified are technical assessments, building oriented research, people oriented research and in-depth qualitative studies, each of which sit at different points along a spectrum running from positivism to phenomenology, with the former two examples sitting further towards the positivist end and the latter two further towards phenomenology. Through an assessment of examples of each approach, we explore the argument that qualitative and discursive research methodologies have a useful role to play, complementing more quantitative approaches in the field of domestic energy. The paper supports this view, underlines the importance of triangulation and recognises the continuing relevance of studies of building performance. It goes further, however, by questioning which of these approaches should take priority. It is concluded that open-ended qualitative research, exemplified by phenomenological and hermeneutic traditions, are better equipped to investigate the home, as experienced and, in doing so, to identify the range of factors that influence domestic energy consumption.

Cathodic protection (CP) has been successfully employed to protect steel-framed masonry buildings from corrosion related damage. When a CP system is installed to protect the structural members, other metallic items which are within the fabric of the structure but are not in direct electrical continuity may suffer from stray current interactions, resulting in accelerated corrosion of the discontinuous items. Therefore, these must be considered when CP systems are designed prior to installation. This paper presents both experimental and numerical studies into the risk and extent of stray current corrosion in steel-framed masonry structures when subject to impressed current cathodic protection. The objective is to allow CP systems to be optimised so that interference is minimised without compromising the technical or cost benefits of this method of corrosion control.

Demolition waste materials mainly consist of concrete\ud and bricks and arise from the demolition of existing\ud structures and buildings. Environmental and economical\ud reasons make their recycling necessary, but to date, their\ud use is curtailed due to the lack of research in determining\ud their properties. This paper reports on the efforts to\ud understand the behavioural characteristics of three types\ud of recycled material to determine their potential for\ud engineering fill applications. For this purpose, their\ud physical and mechanical characteristics were extensively\ud investigated. Two types of crushed concrete, one\ud obtained straight after demolition and the other processed\ud to industry specifications, and one type of crushed\ud brick were tested. An extensive large-scale shear box test\ud regime was employed to determine the shear strength\ud behaviour of the materials. The influence of the normal\ud stress on the peak friction angle, the shear stress–\ud horizontal displacement relationship and horizontal displacement–\ud vertical displacement behaviour of the materials\ud are discussed in this paper. The results showed that\ud the behaviour of the three recycled materials during\ud shear testing was similar to the behaviour exhibited by\ud natural granular materials from literature. In conclusion,\ud the shear box test results have shown that the specific\ud demolition waste products exhibit considerable shear\ud strength and can be utilised in construction as low-level\ud engineering fill.

Demolition waste materials, such as crushed concrete and bricks, have been utilised by the UK construction industry for applications such as the production of concrete, low-level backfill and road sub-base. There has been increased research into the properties of the recycled aggregates in the past decade but it mainly concentrates on the strength of these types of materials through shear box and triaxial tests. Little research has been undertaken on the physical properties of recycled materials, such as particle shape, water absorption and freeze–thaw resistance. This paper addresses the investigation of the physical properties of demolition waste materials for the purpose of re-use as engineering fill. It presents the physical characteristics of three types of commercially crushed concrete and brick materials, two of them being similarly based crushed concrete materials with different degrees of processing and one being crushed brick. Characteristics such as particle size distribution, particle shape, large-scale compaction, resistance to freeze–thaw and aggregate impact, and crushing values were established. The results show that there are similarities and differences between the two concrete-based materials. The characteristics of the brick-based materials are significantly different from the crushed concrete materials.

The present paper presents the influence of resistivity on the current and potential distribution of cathodic protection (CP) systems for steel framed masonry structures. The work involves both experimental measurements and boundary element analysis and follows on from earlier experiments employing sand as a simple model for masonry encasement that has been reported elsewhere. Factors such as the size and type of masonry, moisture content and width of mortar joints will affect the resistance of the path through which the CP currents pass and thereby influence the distribution onto the steel surface. To represent such variations in resistance, it has been necessary to construct a small scale specimen replicating, as far as possible, actual applications on steel framed structures. The results from the laboratory specimen and numerical modelling are in sufficient agreement to confirm the validity of the modelling approach and allow the results to be employed for the purposes of design and development.

Reinforced concrete beams are normally designed as under-reinforced to provide ductile behaviour i.e. the tensile moment of resistance, M t(0) is less than the moment of resistance of the compressive zone, M c . The degree of under-reinforcement (M t(0)/M c ratio) can depend upon the preferences of the designer in complying with design and construction constraints, codes and availability of steel reinforcement diameters and length. M t(0)/M c is further influenced during service life by corrosion which decreases M t(0). The paper investigates the influence of M t(0)/M c on the residual flexural strength of corroded beams and determines detailing parameters (e.g. size and percentage of steel reinforcement, cover) on M t(0)/M c . Corroded reinforced concrete beams (100 mm × 150 mm deep) with varying M t(0)/M c ratios were tested in flexure. The results of the investigation were combined with the results of similar work by other researchers and show that beams with lower M t(0)/M c ratios suffer lower flexural strength loss when subjected to tensile reinforcement corrosion. Cover to the main steel does not directly influence M t(0)/M c and, thus, the residual flexural strength of corroded beams is not normally affected by increased cover. A simplified expression for estimating the residual strength of corroded beams is also given.

Guidance for highway bridge and structure maintenance management in the UK is provided by the code of practice (CoP) 'Management of Highway Structures'. With regards to inspection of reinforced concrete beams in accordance with the code, the professional judgement of the bridge engineer is required to assess the extent and severity of deterioration with help from a library of different defects. The Extent of the defects is rated A – E whilst the Severity is scored 1 – 5, giving an Extent and Severity score for each element, known as the element condition score. However, the Code does not provide information on the corresponding levels of corrosion in the steel reinforcement in the damaged beam. The purpose of this paper is to relate the element severity scores for a range of damaged reinforced concrete beams to approximate levels of corrosion of the main steel, thereby giving the bridge inspector an understanding of the seriousness of corrosion for each of the five Severity scores.

Cathodic protection has been proven to be one of the most widely applicable and cost-effective solutions for tackling steel corrosion in reinforced concrete. In this study, the possible use of carbon fibre composites, which are primarily used to strengthen concrete members, has been investigated as impressed current cathodic protection anodes. Carbon fibre anodes have been assessed in both concrete and calcium hydroxide solution. Two bonding mediums incorporating epoxy and geopolymer have also been investigated. The results demonstrate that epoxy resin can be used for bonding carbon fibre fabric anodes to reinforced concrete structures while geopolymer is more effective for bonding carbon fibre reinforced polymer (CFRP) rod into preformed grooves in the concrete surface. The dissolution of carbon fibre anode appears to stablise after a period of time, dependent upon the size and shape of the anode and applied voltage and current. Based on the present results, a maximum current density of 128 mA/m2 of reinforcing steel area is recommended for the operation of CFRP fabric anode and 64 mA/m2 of reinforcing steel area for that of CFRP rod anode.

Many high-profile steel-framed masonry buildings are susceptible to extensive damage as a result of corrosion of the steel frame. This has resulted in serious consequences with respect to serviceability, safety, aesthetics and heritage. Cathodic protection (CP) is a proven method for preventing and protecting buried and submerged steel and reinforced concrete structures from corrosion. More recently, the method has been introduced to prevent and control corrosion in steel-framed masonry structures. However, despite several sizeable CP installations around the world, there are no formal guidelines for the design, installation and operation of such systems and much of the\ud knowledge is based on empirical observations. This paper presents both experimental and numerical studies on the cathodic protection of representative steel framed masonry structures. These studies are considered essential in the understanding of the mechanisms of cathodic protection and the design of optimised cathodic protection systems for such structures.

This paper outlines two procedures for determining the interfacial shrinkage stresses in a repair patch. The first is an analytical approach based on the analogy of a bimetallic strip undergoing contraction (shrinkage). The second is a semi-empirical procedure based on strain monitoring of in situ repairs to in-service bridges. The procedures determine conversion factors to relate the specified properties of the repair materials to their in situ properties in a field repair patch. For example, the shrinkage of a repair patch is influenced by the volume–surface effect, site temperature and relative humidity which are not considered in repair material specification. Creep is initiated in situ by differential shrinkage stresses in the repair material and is determined by adopting an effective elastic modulus approach. Both procedures require the basic material properties (elastic modulus, shrinkage, creep) and geometrical details (width, depth) of the repair patch. The analytical approach incorporates the repair material creep coefficient to predict the interfacial tensile stresses. Alternatively, it uses a less rigorous, elastic approach that omits creep. The creep approach provides higher accuracy whereas the elastic approach overestimates stresses since relaxation by creep is neglected. The elastic approach is recommended for design due to its simplicity and the in-built factor of safety provided by the overestimation of tensile stress. The semi-empirical approach uses an expression derived from long-term field data to determine the strain (and consequently stresses) at the interface of the repair patch and the substrate concrete. The procedures predict the maximum interfacial tensile stress during the service life of a repair patch. They can be used to design crack-free repair patches and optimise repair material selection through a better understanding of the interaction between the repair patch and substrate concrete.

Long-period gratings, which display sensitivity to ambient temperature variations, are proposed as sensors. Therefore, full temperature characterisation is essential. In this paper, the effects of temperature upon the spectral profiles of two sets of long period gratings (LPGs) of different periods are investigated. The results obtained show that the shorter-period LPGs were found to be less sensitive than the longer-period LPGS over identical temperature ranges. The coupling wavelength shifts due to temperature are also seen to be linear and in opposite directions in each set of LPGs.

This paper presents the results of laboratory and field investigations of bridge beams repaired both under propped and unpropped conditions. In the laboratory, beams were repaired using hand-applied repairs. Repairs to beams in two highway bridges were carried out using both hand-applied and flowing repairs. The repair materials used were commercial products of wide-ranging properties (shrinkage, creep and elastic modulus). Both low stiffness repair materials of elastic modulus, Erm, less than the substrate Esub, and high stiffness repair materials (Erm > Esub) were used. The repairs were applied in the tensile zone of the beams. Strain distributions in the different phases of repair patches were monitored under service loading for a period of up to 240 weeks. The results show that high structural efficiency is achieved with repairs having Erm > Esub, other properties (shrinkage and creep) being within reasonable limits. Such repairs are less prone to restrained shrinkage cracking and show a capacity for load redistribution into the repair patch. Low stiffness repairs (Erm < Esub), on the other hand, are prone to restrained shrinkage cracking and are ineffective in load-sharing with the substrate. Repairs to propped flexural members developed erratic and non-uniform load distribution in the different phases upon reapplication of load. Composite action between the repair patch and the substrate results in cracking in the repair patch, rendering the repairs structurally inefficient.