Joint seals for hydraulic structures in severe climates

This paper presents laboratory test data on 21 joint seals: 10 field-moulded sealants (FMS; 1- and 2-components polyurethanes, polysulphides, silicones, etc.) and 11 preformed seals (neoprene, silicone, high-density open-cell and low-density closed-cell foams, etc.). The aim was to evaluate their performance in submerged, partially submerged and essentially dry conditions in extremely severe climates. These seals were tested on cement mortar substrates as well as on steel substrates. The tests carried out on FMS were: adhesion-in-peel strength, compression-extension cycling at severe temperatures, Shore A hardness, weatherability and modulus of elasticity, etc. On preformed seals, the tests conducted were weatherability, % recovery and load deformation behaviour, etc. Conclusions, recommendations and the specific suitability of joint seals with cement mortar and steel substrates are reported. The general conclusion is that even though the joint seals evaluated had similar base chemical constituents, they showed variable results. Their properties and characteristics differ from one manufacturer to others, indicating that prior knowledge about their performance is essential to the user. Furthermore, the published data on the performance of seals used in hydraulic structures situated in severe climatic conditions is sparse. It is recommended that utilities publish as much information as possible to help others

Mortars and Concrete Incorporating Palm Oil Fuel Ash and Fly Ash

Number of researchers reported that Palm Oil Fuel Ash (POFA) and Fly Ash (FA) can be used as supplementary cementing material (SCM) in concrete. Both materials have their own significant effects on the properties of concrete and have been accepted by using them for the improvement of workability and strength of concrete. However, studies showed that FA has better pozzolanic properties than POFA. Hence, properties of mortars blended with POFA (untreated and treated) as binary blend (CUP and CTP) and ternary blend that combined with FA (CUPF and CTPF) as cement replacement were investigated. Unground POFA has been used in this study. CUPF and CTPF resulted in significant improvement in the pozzolanic activity compared to CUP and CTP of mortar mix. Pozzolanic activity of ternary blend mortar achieved the specified pozzolanic activity index of 75% based on ASTM C618. Compressive strength of the C80P15F5 concrete with 15% of treated POFA + 5% of FA by weight of binder showed a slightly higher result compared to the control mix. It is suggested that the combination of POFA and FA as pozzolanic material will improves the mechanical properties of mortars and concrete

Review of Sartre's Thoughts in the Works of Jalal Al-Ahmad Focusing on the Story of “the life who escaped”

. IntroductionExistentialism is one of the philosophical schools that, due to its emphasis and special view on "human", find its way into literature, especially into novels and plays. This school was first founded in Germany by Kierkegaard in the 19th century (Rasekhi langaroudi, 2018:18), and then Jean-Paul Sartre spread it in France.In this school, the human is a lonely and abandoned being who has to do something for himself because there is no helper or necessary existence. Existentialism became popular in Iran in the forties and fifties and many were influenced by it and created many works inspired by it. Jalal Al-Ahmed was one of the intellectuals and writers of that period, who was influenced by Sartre's thoughts at some point in his activities. As a committed writer, he described the suffering of a simple porter worker in the short story "The life who escaped" in order to find a way out of the chaos and social injustice. This article tries to examine the concept of suffering in this story and in this way evaluate the influence of Sartre's thoughts on Al Ahmed. In this research, the mentioned subject has been analyzed in a descriptive-analytic way and with a comparative approach, using some elements and components of the school of existentialism. The results of this research indicate that the suffering that Al-Ahmed portrays in his story is not due to frustration and passivity, but rather by portraying this suffering, he seeks to find a way to improve and enhance the troubled situation of the workers and such viewpoint stems from the theory of "committed literature" that Sartre talks about.  MethodologyIn this research, the mentioned subject has been analyzed in a descriptive-analytical way and with a comparative approach, using some elements and components of the school of existentialism.  DiscussionUndoubtedly, the environmental factors and the socioeconomic conditions of the post-World War II played a decisive role in the spread of Sartre's existentialism philosophy (Dastgheib, 1975: 75).  This philosophy was trying to free human thought from the prison of restrictive rules, deception and trickery. After the two world wars, people realized the futility of existence and the baselessness and bewilderment of existence and such mental turmoil made them understand anxiety, apprehension, loneliness and destitution more than before. Due to the prevailing political and social atmosphere of Iran in the 40s and 50s, Sartre's ideas soon found their way into intellectual circles as an effective discourse. Many intellectuals, writers and translators who objected to oppression and injustice became fascinated by concepts such as " human absolute freedom", "responsible intellectual" and "writer's commitment". The philosophy of existentialism seeks awareness and responsibility to fill the void of meaning in life. Such a view of human beings in a world that is engulfed by disorder and injustice affected Al Ahmad like many others.Sartre held responsibility for the writer and believed that the writer should be committed to his society and people. According to Sartre, the writer was obliged to help build a better world by writing about the injustices and deficiencies of society. Under the influence of such social function of literature and the author's commitment, Al-Ahmad, as a concerned intellectual, paid attention to the underprivileged and deprived society class in his stories (Rahimi, 2015:80). As two committed writers, Jean-Paul Sartre and Jalal Al-Ahmed, both deeply believed in the commitment and responsibility towards society. They saw writing as a means to raise public awareness and depict the pains and adversities in society and life.The short story "the life who escaped" is from the short stories collection of "Setar". Setar is the third short story collection of Al Ahmad after "Visiting" and "Of our sufferings". "The life who escaped" is an existentialist story and the roots of Sartre's philosophical ideas and Al-Ahmed's devotion to ideas such as Loneliness, doubt and inner conflict is obvious in the main essence of this story.In the story "The life who escaped", the worker is in a situation from which he has no escape. Either he must deliver the cargo to the destination where he will get money so that he does not die of hunger, or he must abandon the cargo, while it is not known whether he can find another job or not. In this story, we see how the deterministic situation casts a shadow on the worker and leads him to the abyss of desperation, helplessness and destitution. The worker finds himself in an absurd world and the more he struggles, the more he sinks into this swamp of absurdity and failure.Sartre believes that a person is constantly involved in different situations throughout his life and only he should decide what to do. He is free to choose and stand by his choice; in "The life who escaped", Al-Ahmed portrays this Sartre notion in a fictional form. After two days of unemployment, a worker decides to work as a porter. He is forcibly pushed into such situation, but soon realizes that he does not have the necessary strength to carry the cargo. According to Sartre, every human in any situation, can act based on his decision. So, the worker must choose between his two options; he has to take the cargo to its destination without any difficulty and accept whatever happens along the way or return it to its original place.According to Sartre, the human being is always in the circle of possibilities. But to a certain extent, he can hope for possibilities that are exactly within his scope of action. It is "action" that makes it possible for humans to live. But "action" itself requires motivation, and this motivation comes from a level of understanding and awareness (Warnock, 2007:47). The poor worker in the story of Al Ahmed is also fully aware of the concept of hunger and knows the meaning of empty pockets and poverty. Such awareness motivates him, despite his physical weakness, to get his cargo to destination in order to earn some money.According to Sartre’s philosophy, man is constantly choosing. In fact, planning and choosing different paths imply her freedom and freedom of action. Man is constantly forced to choose. So, man is always free and at the same time, he has to choose. Man has no way to escape from these decision makings. So, as Existentialists say: "human is condemned to freedom".  Al-Ahmad also shows in a fictional and symbolic way how important the consequences of human choices are and well depicts that humans can be selective in any position and situation; even in the position of a daily worker who must carry a cargo to earn some money and get rid of his hunger. The worker can choose to get the cargo to its destination or take it back to its first place and free himself from the responsibility which is beyond his power and abilities. We are only watching the struggle of the worker who wants to push back his submission to despair as far as he can.  ConclusionAs a committed thinker and writer, Jalal Al-Ahmad always sought to create an escape route from the political and cultural dead ends and find a way to get out of the chaotic social situation. Influenced by Sartre and others such as Camus and Celine, he started writing realistic stories. Stories that narrate the pains and sufferings of downtrodden and oppressed people. Hoping to draw public attention to social problems and take a step, even a small one, toward their correction.He narrates the helplessness of an abandoned human well in the story "The life who escaped". The man in Al-Ahmed's story, in a symbolic way, must take responsibility for the heavy burden that is on his shoulders. There is no one to help him. The worker in Al Ahmed's story, with all his desperation, is free, as free as Sartre has repeatedly pointed out. from the existentialist viewpoint, all humans are free, even a prisoner, a cripple or a man under the gallows.In his suffering image, Al-Ahmad is looking for existential possibilities that implicitly open a way to hope, life and justice.

Standardization of composite connections for trapezoid web profiled steel sections

Connections are usually designed either as pinned usually associated with simple construction or rigid normally is associated with continuous construction. However, the actual behaviour falls in between these two extreme cases. The use of partial strength or semi-rigid connections has been encouraged by Euro-code 3 and studies on semi-continuous construction have shown substantial savings in steel weight of the overall construction. Composite connections are proposed in this paper as partial or full strength connections. Standardized connection tables are developed based on checking on all possible failure modes as suggested by "component method" for beam-to-column composite connection on major axis. Four experimental tests were carried out to validate the proposed standardised connection table. The test results showed good agreement between experimental and theoretical values with the ratio in the range between 1.06 to 1.50. All tested specimens of the composite connections showed ductile type of failure with the formation of cracks occurred on concrete slab at maximum load. No failure occurred on the Trapezoidal Web Profiled Steel Section as beam and on the British Section as column

Synthesis and characterization of shelf-healing mortar with modified strength

Cementitious materials being the most prospective building blocks achieving their absolute strength to avoid the deterioration in the early stage of service life is ever-demanding. Minimizing the labor and capital-intensive maintenance and repair cost is a critical challenge. Thus, self-healing mortars with modified strength are proposed. Lately, self-healing of micro-cracks by introducing bacteria during the formation of mortar or concrete became attractive. Self-healing with polymeric admixtures is considered to be relatively more durable and faster process. Certainly, the self-healing of synthetic polymeric materials is inspired by biological systems, where the damage triggers an autonomic healing response. This emerging and fascinating research initiative may significantly improve the durability and the safety limit of the polymeric components potential for assorted applications. In this work, using epoxy resin (diglycidyl ether of bisphenol A) without any hardener as admixture polymeric-cementitious materials is prepared. These epoxy-modified mortars are synthesized with various polymer-cement ratios subjected to initial wet/dry curing (WDC) together with long term dry curing (DC). Their self-healing function and hardening effects are evaluated via preloading and drying of the specimens, chemical analysis, and ultrasonic pulse velocity testing. It is demonstrated that 10% of polymer is the best proportion for polymer-cement ratio. Furthermore, the wet/dry curing is established to be superior process for healing hairline cracks present in the mortar. The excellent features of the results suggest that our novel method may constitute a basis for improving the compressive strength and self-healing features of mortars

Mechanical properties of self-compacting geopolymer concrete containing spent garnet as replacement for fine aggregate

Millions of tons of spent garnet, a by-product of surface treatment operations, are disposed of in landfills, oceans, rivers, and quarries, among others every year, thus it causes environmental problems. The main objective of this study is to evaluate spent garnet as a sand replacement in concrete prepared with ground granulated blast furnace slag (GGBS)-based self-compacting geopolymer concrete (SCGC). Concrete mixtures containing 0%, 25%, 50%, 75% and 100% spent garnet as a replacement for river sand were prepared with a constant Liquid/Binder (L/B) mass ratio equal to 0.4. Compressive, flexural and splitting tensile strengths as well as workability tests (slump, L-box, U-box and T50) were conducted on concrete containing spent garnet. As per specification and guidelines for self-compacting concrete (EFNARC) standard, the test results showed that the concrete’s workability increased with the increase of spent garnet, while all the other strength values were consistently lower than conventional concrete (SCGC) at all stages of replacement. The results recommended that spent garnet should be used in concrete as a sand replacement up to 25% to reduce environmental problems, costs and the depletion of natural resources

Mechanical, thermal and durable performance of wastes sawdust as coarse aggregate replacement in conventional concrete

Wood yields a number of by-products and Sawdust is as useful as others. Sawdust is regarded as a waste material and is effectively utilised as sawdust concrete in the construction of buildings. It is capable to be utilised as light-weight concrete and holds the quality of long duration heat transfer. In this study, three different ratios (1:1, 1:2 and 1:3) volume mix proportions of cement to sawdust were adopted to make sawdust concrete. At varied intervals of 7, 28 and 56 days of air curing, thermal and mechanical properties like workability, density, elastic modulus, strength and heat transfer were probed of mentioned sawdust concrete proportions. The resistance to elevated temperatures was also evaluated after 28 days of age; weight loss, residual compressive strength, surface texture and ultrasonic pulse velocity were considered in evaluation process. The findings showed that increase in sawdust volume affected to decrease the workability, strength and elevated temperatures resistance. However, the concrete having higher proportion of sawdust performed competently and well in terms of thermal conductivity. Moreover, a decrease in the heat transfer of sawdust was also observed. Examining the all-embracing mechanical and physical properties, sawdust can be effectively utilised in the construction of buildings

Activation of slag through a combination of NaOH/NaS alkali for transforming it into geopolymer slag binder mortar – assessment the effects of two different Blaine fines and three different curing conditions

This study investigates the effects of two different Blaine fineness and three distinct curing conditions on the physico-mechanical properties of a geopolymer-ground granulated blast furnace slag (GGBFS) binder mortar activated through a combination of NaOH/NaS alkalis. By ensuring constant curing and mixing conditions, geopolymer mortar (GPM) specimens were prepared and evaluated to determine their capillary water sorption, capillarity coefficient, and change in unit weight, alongside their compressive strength and flexural strength 3, 7, 28, and 56 d after production. It was found that the capillary water sorption decreased by approximately 50% as the curing temperature of the water increased from ambient temperature to 22 °C. The coefficient of capillarity remained constant across the geopolymer materials, irrespective of the Blaine fineness of the GGBFS. Furthermore, the increase in the unit weight, owing to the variation in the Blaine fineness of GGBFS, results in a reduction in the water sorption properties of GPMs. The GGBFS and alkali-based binders imparted a continuous increase in the compressive and flexural strengths. The results revealed that a Blaine fineness of 6000 cm2/g in the GGBFS under water-curing conditions imparted the most significant advantageous effect on the physico-mechanical properties of a GGBFS binder mortar activated through a combination of NaOH/NaS alkalis