Tigger paper : integration

The process of architecture will always be holistic. As long as it is taught in segments, its educational structure will always run the risk of failing to meet this primary educational aim, and be continually shooting itself in the foot. The pedagogical and professional advantage to breaking the perceived lack of integration between studio and subject classes is I believe a fundamental imperative, to recognise that every part of the architectural process is not in contradiction but has equal value, and to realise the added value that integration would bring to all parts of the educational process, to staff and student alike

Effect of temperature on RC elements strengthened with CFRP

The strengthening of RC elements with CFRP is a technique that has been acquiring more and more potential. The bond between the CFRP reinforcement and the concrete support is usually made with epoxy adhesives. However, it is here that the integrity of the system can be affected, namely by exposure to high temperatures. In order to study the effect of an increase of air temperature on the behaviour of the epoxy adhesive, CFRP strengthened RC and reference RC specimens were tested. After cyclical thermal exposures, with temperatures rising between 20ºC and 80ºC, specimens were subjected either to compressive shear tests or bending tests. The results demonstrated that epoxy adhesive exhibits poor behaviour when subjected to increased temperatures, causing important bond deterioration. The improvement achieved with the CFRP reinforcement tends to disappear with an increase of the environment temperature. So, the thermal resistance of this strengthened system can not be considered very high. However, the inclusion of insulating materials can be a good solution to protect the strengthened RC elements. Among tested materials, the foamed polyurethane showed the best behaviour

Aggregate effect on the concrete cone capacity of an undercut anchor under quasi-static tensile load

In the last decades, fastening systems have become an essential part of the construction industry. Post-installed mechanical anchors are frequently used in concrete members to connect them with other load bearing structural members, or to attach appliances. Their performance is limited by the concrete related failure modes which are highly influenced by the concrete mix design. This paper aims at investigating the effect that different aggregates used in the concrete mix have on the capacity of an undercut anchor under tensile quasi-static loading. Three concrete batches were cast utilising three different aggregate types. For two concrete ages (28 and 70 days), anchor tensile capacity and concrete properties were obtained. Concrete compressive strength, fracture energy and elastic modulus are used to normalize and compare the undercut anchor concrete tensile capacity employing some of the most widely used prediction models. For a more insightful comparison, a statistical method that yields also scatter information is introduced. Finally, the height and shape of the concrete cones are compared by highly precise and objective photogrammetric means

Effect of river indus sand on concrete tensile strength

In the development of Pakistan construction industry, the utilization of River Indus sand in concrete as fine aggregate has expanded tremendously. The aim of this research is to study the effect of Indus River sand on the tensile strength of various grades of concrete when it is utilized as fine aggregate. Concrete Samples of M15, M20 and M25 grade concrete were cured for 7, 14, 21 and 28 days. Based on the results, it is found that concrete became less workable when Indus river sand was utilized. It is recorded that tensile strength of concrete is decreased from 5% up to 20% in comparison with hill sand. The results were derived from various concrete grades

The effect of polypropylene fibres within concrete with regard to fire performance in structures

Purpose – The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires. Design/methodology/approach – Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark following high temperature heat tests to evaluate the surface condition and final compressive strength. A pilot study was used to determine an appropriate heat source for the test. This was three Bunsen burners, however sufficient heat could not be generated within 150mm concrete cubes and the concrete was shown to be a significant insulator and fire protection for structural members. The concrete test cubes were tested in a saturated condition which may reflect conditions where concrete is used in an external environment and thus is subject to soaking. Findings – One hundred and fifty millimetre concrete cubes with and without fibres were placed into a furnace at 1,000°C. Explosive spalling was shown to be reduced with the use of polypropylene fibres but the final compressive strength of concrete was significantly reduced and had little residual structural value after a two hour period of heating. Research limitations/implications – As the concrete tested was saturated, this condition provided a worst case scenario with regards to the build up of hydrostatic and vapour pressure within the cube. A range of percentage moisture contents would produce a more evenly balanced view of the effects of fibres in concrete. A single grade of concrete was used for the test. As the permeability of concrete influences the rate at which steam can escape from the interior of a saturated concrete cube, testing a range of concrete strengths would show this aspect of material performance with regard to spalling and final residual strength. Further research is recommended with regard to moisture contents, strengths of concrete and a range of temperatures

Effect of material properties on ductility factor of singly rc beam sections

Ductility may be defined as the ability to undergo deformations without a substantial reduction in the flexural capacity of the member. The ductility of reinforced concrete beams depends mainly on the shape of the moment-curvature relationship of the sections. The constituents of reinforced concrete are very complex due to its mechanical properties. The stress-strain behavior of concrete is considered parabolic and that of the steel is elastic plastic. Concrete and reinforcing steel are represented by separate material models that are combined together to describe the behavior of the reinforced concrete sections. The end displacements of the steel element are assumed to be compatible with the boundary displacements of the concrete element which implied perfect bond between them. The curvature ductility factor of singly reinforced concrete rectangular beams is derived taking into account the possible nonlinear behavior of the unconfined compressed concrete and reinforcing steel. Effects of material properties such as concrete compressive strength, reinforcement ratio and yield strength of reinforcement on the curvature ductility factors are derived analytically. From the analyses it is observed that an increasing steel content decreases the curvature ductility of a singly reinforced concrete section and this pattern is valid for any concrete strength. On the other hand, for the same reinforcement content curvature ductility increases as the concrete strength is increased

KAPASITAS LENTUR, TOUGHNESS, DAN STIFFNESS BALOK BETON BERSERAT POLYETHYLENE

Abstract The common problems of concrete are brittle failure and low of tension. Fiber reinforced plastic concrete is one of the alternatives to solve the problems. This research aim is to demonstrate a contribution of Polyethylene to revise the weakness of its properties. An experiment has been conducted to observe compressive strength, toughness, modulus of rupture and stiffness of fiber-polyethylene-reinforced concrete. The results show that by adding Polyethylene as a fiber in concrete material, compressive strength increases to 120.36%, moment capacity of beam increases to 115.79% and toughness increases to 318.6% compared with normal concrete. Hence, it can be stated that the addition of Polyethylene fiber has a significant contribution to increase the concrete performances. Keywords: concrete, fiber, polyethylene, stiffness, toughness

From Cambridge to Brighton: Concrete poetry in Britain, an interview with Stephen Bann

Extensive interview with art historian, curator and concrete poet Stephen Bann by Gustavo Grandal Montero, focusing particularly on his curatorial, critical and artistic work of the 1960s, closely involved with the development of Concrete poetry in the UK. Associated at an early stage with Ian Hamilton Finlay, he co-organized the First International Exhibition of Concrete and Kinetic Poetry (Cambridge, 1964) and was Director of the Concrete Poetry Exhibition for the inaugural Brighton Festival in 1967, edited Concrete poetry: an international anthology 1967 and published several influential critical texts, while developing his own Concrete poetry practice

Behavior of axially loaded circular stainless steel tube confined concrete stub columns

A stainless steel tube confined concrete (SSTCC) stub column is a new form of steel-concrete composite column in which the stainless steel tube without bearing the axial load directly is used to confine the core concrete. It could take the advantages of both the stainless steel tube and the confined concrete columns. This paper presents the experimental investigation of circular SSTCC stub columns subjected to axial load. Meanwhile, comparative tests of the circular concrete-filled stainless steel tubes and circular hollow stainless steel tubes were also conducted. The experimental phenomena of specimens are introduced in detail and the experimental results are analyzed. Through the investigation of axial stress and circumference stress on the stainless steel tube, the interaction behavior between stainless steel tube and core concrete is studied. The experimental results showed that the stainless steel tube provides better confinement to the concrete core, thus results the compressive capacity increased obviously comparing with unconfined concrete. The load-carrying capacity of SSTCC stub columns is higher than that of concrete-filled stainless steel tubes. An equation to calculate the load-carrying capacity of SSTCC stub columns was proposed, the results based on calculation are close to the experimental results

Strength and water absorption rate of concrete made from palm oil fuel ash

Concrete is one of the most important materials for construction industry. The material in the mixture of concrete includes cement, sand and coarse aggregate. Production of cement causes the air pollution from the emission of carbon dioxide to the air. This research studies the replacement of cement with palm oil fuel ash (POFA) in the concrete mixture. The objective of this research is to investigate the compressive strength of concrete and water absorption rate of concrete made from POFA and to compare the strength and absorption rate between conventional concrete and concrete made from POFA. This is to indicate whether the compressive strength and absorption rate are equivalent to the strength of conventional concrete. The methodology used in this research is experimental method and the palm oil fuel ash was taken from palm oil mill in Cha’ah, Johor, Malaysia. The results of this research are the specimens which contain 20% POFA has a compressive strength and water absorption rate comparable to conventional concrete