Concrete Technology

This is a doppler device, based on heterodyning with a laser source. Its features include a very large DoF and dynamic range. • Spherical projectiles, 14 mm. • Projectiles could be observed through cavity • From V(t) integrate to get V(x) or differentiate to get dV/dt.

La mayor parte de los deterioros en las estructuras de hormigón armado se deben a la corrosión. En este artículo se presenta una metodología clara, que permite predecir cuantitativamente la vida útil de las estructuras de concreto armado frente al ataque de iones cloruro a través de la utilización de modelos de difusión de cloruros. Es mostrada la aplicación de la metodología a un caso de estudio en el cual se han seguido las prescripciones de las normas de durabilidad. Los resultados de estimación de la vida útil son contrastados con las recomendaciones utilizadas comúnmente demostrando la necesidad de los análisis de vida útil.

La mayor parte de los deterioros en las estructuras de hormigón armado se deben a la corrosión. En este artículo se presenta una metodología clara, que permite predecir cuantitativamente la vida útil de las estructuras de concreto armado frente al ataque de iones cloruro a través de la utilización de modelos de difusión de cloruros. Es mostrada la aplicación de la metodología a un caso de estudio en el cual se han seguido las prescripciones de las normas de durabilidad. Los resultados de estimación de la vida útil son contrastados con las recomendaciones utilizadas comúnmente demostrando la necesidad de los análisis de vida útil.

The modern increase in building construction sector is resulting in get larger production of fine sand. The marble industry of India is account one of the chief decorative building material industry. With the increase in production of marbles it increases the waste that get from it. Marble dust creates environmental problems. Due to environmental problems, it affects Human health as well as nature. As marble dust is the waste product, get during the sawing and polishing of marble by parent marble block and about 20-25% of the processed marble is turn into dust form. The production of cheaper concrete using waste marble dust can solve to some extent the ecological and environmental problems. Therefore this paper aims to study the effect of using marble dust as partially replace of fine sand on concrete.

This Research paper is a live study on the above mentioned title "Recycling of Concrete" This paper consist the introduction of recycled concrete aggregate with its uses and properties. Various test results on Recycled concrete aggregate also described. It also consist the difference between RCA and natural aggregate. The future recommendations are also discussed in addition. Keywords-Recycled Coarse Aggregate (RCA), Concrete Mix Design(CMD), Natural Aggregate(NA) I.

This Research paper is a live study on the above mentioned title “Recycling of Concrete” This paper consist the introduction of recycled concrete aggregate with its uses and properties. Various test results on Recycled concrete aggregate also described. It also consist the difference between RCA and natural aggregate. The future recommendations are also discussed in addition. Keywords—Recycled Coarse Aggregate (RCA), Concrete Mix Design(CMD), Natural Aggregate(NA)

Corrosion in concrete prevents in-situ observation, necessitating models to provide insight into the local reaction currents. We present a computational method for predicting corrosion rates of reinforcements within concrete under natural conditions, i.e. requiring the corrosion current to be supported by equal cathodic currents. In contrast to typical corrosion models, where these two counteracting currents are required to be co-located, we allow these currents to be separated such that pitting corrosion can be supported by cathodic reactions over a much larger area. Pitting corrosion is investigated, elucidating the effects of the concrete porosity and water saturation, the presence of dissolved oxygen, and chlorine concentration within the pore solution. The presented model is capable of capturing the dynamic growth of acidic regions around corrosion pits, showing the limited region over which the hydrogen evolution reaction occurs and how this region evolves over time. The ability of oxygen to diffuse towards the metal surface due to increased porosity is seen to have a major effect on the corrosion rate, whereas changes in the chlorine concentration (and thus changes in the conductivity of the pore solution) play a secondary role. Furthermore, external oxygen is seen to enhance corrosion but is not required to initialise and sustain acidic corrosion pits.

Pervious concrete is a very special type of concrete with high porosity made using large aggregates with little to no fine aggregates. It allows water from precipitation and other sources to pass directly through thereby reducing the runoff from the site and allowing ground water recharge. The study proposes the replacement of natural coarse aggregates in the mixture, with recycled coarse aggregates. The utilization of recycled coarse aggregates from construction and demolition wastes serves as a sustainable solution, which reduces the overall cost and environmental pollution. In this paper, a review on mechanical properties and permeability indices of pervious concrete made with recycled coarse aggregates is studied.

Beton ve betonarme yapılarda göçme analizi yapılırken birçok lineer ve lineer olmayan yaklaşımlar kullanılmaktadır. Betonarme bir yapıyı kırılma mekaniğine göre analiz edebilmek için ilk önce, kullanılan malzemenin kırılma parametrelerinin belirlenmesi gerekir. Betondaki neme ve zamana bağlı olarak mekanik sabitlerin değişmesi ve boyut etkisinden dolayı, Lineer Elastik Kırılma Mekaniği (LEKM), kırılma parametrelerinin tespitinde yetersiz kalmıştır. Bunun nedeni çatlağın ucunda yer alan diğer malzemelere göre daha büyük bir yer işgal eden kırılma süreci bölgesinin (KSB) var olmasıdır. Betonun kırılma parametrelerini belirlemek için şartnameler ve araştırmacılar tarafından birçok lineer olmayan kırılma mekaniği modelleri önerilmektedir. Bu lineer olmayan yaklaşımlardan boyutun dayanım üzerindeki etkisini inceleyerek betonda daha büyük bir KSB olduğunu öne sürmüş ve 'Boyut Etkisi Kanunu' geliştirmiştir. Betonun kırılma mekaniğinde kiriş numuneler yaygın olarak kullanılmakla birlikte, taşınabilirlik ve hafiflik açısından bazı avantajlara sahip olduğundan küp ve silindir numuneler son zamanlarda kullanılmaya başlanmıştır. Bununla birlikte karşılıklı basınç kuvveti uygulanan küp yarma testi ile ilgili deneysel ve teorik çalışmalar oldukça sınırlıdır. Sunulan bu çalışmada, su/çimento oranı 0.6 olan, maksimum agrega çapı 8 mm'lik kesikli ve sürekli granülometrili beton karışımları hazırlanmıştır. Aynı geometriye sahip farklı boyutlu (4:2:1) küp numuneler üzerinde boyut etkisi incelenmiştir. 50x50x50 mm 3 , 100x100x100 mm 3 , 200x200x200 mm 3 'lük küp numunelerin 28 günlük yarmada-çekme dayanımları belirlenmiş, elde edilen deney sonuçları Bazant'ın "Boyut Etkisi Kuralı"na göre analiz edilmiştir. Sonuç olarak kesikli granülometriye sahip betonların daha sünek davrandığı tespit edilmiştir.

Severe environmental conditions, coupled with the routine use of deicing chemicals and increasing traffic volume, tend to place extreme demands on portland cement concrete (PCC) pavements. In most instances, engineers have been able to specify and build PCC pavements that met these challenges. However, there have also been reports of premature deterioration that could not be specifically attributed to a single cause. Modern concrete mixtures have evolved to become very complex chemical systems. The complexity can be attributed to both the number of ingredients used in any given mixture and the various types and sources of the ingredients supplied to any given project. Local environmental conditions can also influence the outcome of paving projects. This research project investigated important variables that impact the homogeneity and rheology of concrete mixtures. The project consisted of a field study and a laboratory study. The field study collected information from six different projects in Iowa. The information that was collected during the field study documented cementitious material properties, plastic concrete properties, and hardened concrete properties. The laboratory study was used to develop baseline mixture variability information for the field study. It also investigated plastic concrete properties using various new devices to evaluate rheology and mixing efficiency. In addition, the lab study evaluated a strategy for the optimization of mortar and concrete mixtures containing supplementary cementitious materials. The results of the field studies indicated that the quality management concrete (QMC) mixtures being placed in the state generally exhibited good uniformity and good to excellent workability. Hardened concrete properties (compressive strength and hardened air content) were also satisfactory. The uniformity of the raw cementitious materials that were used on the projects could not be monitored as closely as was desired by the investigators; however, the information that was gathered indicated that the bulk chemical composition of most materials streams was reasonably uniform. Specific minerals phases in the cementitious materials were less uniform than the bulk chemical composition. The results of the laboratory study indicated that ternary mixtures show significant promise for improving the performance of concrete mixtures. The lab study also verified the results from prior projects that have indicated that bassanite is typically the major sulfate phase that is present in Iowa cements. This causes the cements to exhibit premature stiffening problems (false set) in laboratory testing. Fly ash helps to reduce the impact of premature stiffening because it behaves like a low-range water reducer in most instances. The premature stiffening problem can also be alleviated by increasing the water-cement ratio of the mixture and providing a remix cycle for the mixture.

Different types of curing compounds were applied to lab and field concrete at different times after casting. Two application methods, single and double layer applications, were employed. Concrete properties, such as electrical conductivity, moisture content, sorptivity, degree of hydration, strength, and permeability were evaluated, and the results were employed for assessment of the curing effectiveness. The investigation indicated that properties of the concrete in the near-surface-area of a pavement without any curing compound were considerably different from those of the internal concrete. Proper curing can significantly increase the moisture content and reduce the sorptivity of the concrete in the near-surfacearea, thus providing the pavement with uniform concrete properties throughout depth. For given concrete materials and mix proportion, water retention ability of a curing material can be estimated by monitoring conductivity of the surface concrete. Sorptivity test for lab specimens appeared a good assessment method for curing effectiveness, and the measurement captured the subtle changes caused by different curing materials and application techniques. These research results established a baseline for rational assessment of curing compound effectiveness in both lab and field concrete.

A two-stage mixing process for concrete involves mixing a slurry of cementitious materials and water, then adding the slurry to coarse and fine aggregate to form concrete. Some research has indicated that this process might facilitate dispersion of cementitious materials and improve cement hydration, the characteristics of the interfacial transition zone (ITZ) between aggregate and paste, and concrete homogeneity. The goal of the study was to find optimal mixing procedures for production of a homogeneous and workable mixture and quality concrete using a two-stage mixing operation. The specific objectives of the study are as follows: (1) To achieve optimal mixing energy and time for a homogeneous cementitious material, (2) To characterize the homogeneity and flow property of the pastes, (3) To investigate effective methods for coating aggregate particles with cement slurry, (4) To study the effect of the two-stage mixing procedure on concrete properties, (5) To obtain the improved production rates. Parameters measured for Phase I included: heat of hydration, maturity, and rheology tests were performed on the fresh paste samples, and compressive strength, degree of hydration, and scanning electron microscope (SEM) imaging tests were conducted on the cured specimens. For Phases II and III tests included slump and air content on fresh concrete and compressive and tensile strengths, rapid air void analysis, and rapid chloride permeability on hardened concrete. 18. Distribution Statement homogeneity-interfacial transition zone-mixing energy-mixing methodsrheological properties-two-stage mixing No restrictions.

The present study has made an emphasis for comparing the strength characteristics of ferrocement panels with panels made with HDPE geogrids. Also, an attempt has been made to replace cement partially by silica fume; which is a by-product obtained from the production of silicon and ferrosilicon alloys in the electric arc furnaces. The rise in the cost of river sand used as fine aggregate in concrete has increased the cost of construction significantly in the past few decades. Foundry Sand, which is obtained from the Foundry Industries are treated as waste materials that have the recycling capability in concrete and it is been proposed for partially replacing sand in this study. Different mix proportions using the above materials have been made and panels were prepared for optimum proportion based on the compressive and tensile strength of cube and cylinder specimens. Panels with two layers of steel mesh and geogrid mesh were cast. A comparative study on strength characteristics has been made and failure patterns of the panels have been studied. It was shown that strength of geogrid panels was on par with ferrocement panels and are advantageous to ferrocement panels in corrosion resistance and elasticity.

In 7 days,14 days and 28 days strength test, compressive strength of concrete increased when the percentage of marble powder waste is increased by 15% and by further increasing of waste marble powder, compressive strength gets reduced. Specimens were casted in (150x150x150) mm moulds.

Cracks are inherent and detrimental elements of building detailed investigation should be carried out regularly to ensure the assessabillity and serviceability of the building. For rehabilitation of cracks it is important to understand the causes and the types of cracks appeared in the structure. This paper shortly describes the causes and types of cracks and their remedial measures. Non destructive testing methods are used to access the strength of the structure at a first instance to know the actual state of the structure whether it will be serviceable/workable or to be demolished. Few case studies were conducted at different public buildings at Gwalior M.P. Political science, economic and archaeological blocks of Jiwaji University. Moti Mahal building.NITM (Nagaji institute of Technology and Management building. Which were reported cracks and they were in suspension to whether it will work or should be demolished. The purpose of this study is to determine the position of structur...

My humble gratitude goes toLafarge Cement Zimbabwe and their Laboratory Staff for selflessly providing the requisite guidance and invaluable support that spurred me to greater heights in terms of personal and professional development and making my researcha successful one. Special indebtedness is also due to my family; I thank them for all the support they have given me be it financial, social and valuable contributions. They prepared me to face challenges with faith and humanity.

Housing is an issue everywhere in the world. Governments
across the world are looking for solutions in the building industry to
provide housing at a reduced cost in the shortest amount of time. The
constraints of conventional construction techniques prevent them from
ever being able to mitigate. Another major issue that humanity currently
faces is global warming. To stop or address this issue, society must adapt
and change its practices to be less damaging to the environment. "Green
buildings" would have a significant impact on this issue. Green buildings
can better use resources while producing healthier buildings that enhance
the environment and human health. On the other hand, new technologies are frequently introduced, and 3D printing is quickly evolving. This
technological innovation is rapidly expanding. There are many
applications for 3D printing right now, and it continues to grow each year.
Even though there are not many 3D-printed liveable structures, this
technology can offer dignified homes to the world's least fortunate
populations. The construction sector may change due to the application of
3D printing technology with green building design principles. This
research emphasises locally obtained materials due to the introduction of
3D printing to the building sector, which reduces the need to transport
concrete over large distances and the energy needed to mix concrete.

The steel portion of the 199A viaduct is a continuous, four-span bridge with 65m-82m-66m-55m long spans which carry two lanes of highway traffic. The horizontal alignment includes spiral portions with a minimum radius of 130m in the main span. The 82m-long main span crosses existing railway lines and the newly constructed south approach viaduct, precluding freedom of crane access in the main span or the possibility of placing temporary piers. This had a big impact on the lifting capabilities of the cranes since they could only be placed outside the railway clearance envelope or on the newly constructed south approach viaduct.

The Deh Cho Bridge is the first bridge structure crossing the Mackenzie, Canada’s longest river. The bridge has permanently replaced ferry and ice road services along Highway 3 connecting Yellowknife in the Northwest Territories with Highway 1 in the South. The bridge’s remote location in the North with severe winter conditions of up to -40 °C required meticulous planning and was an extraordinary challenge for men and equipment (see Figure 1). Innovative design methods led to the design of a unique 1045 m long continuous cable supported superstructure with expansion joints only at the abutments. The design employs ecological lightweight design principles as well as fast-tracked fabrication and erection methods. Structural performance of the superstructure has been optimized for construction and service scenarios allowing a high degree of repetition as well as aesthetic proportions and rhythm. Serious design challenges often require new philosophies and strategies. On the other hand,...

Strength, shrinkage and creep of concrete in tension and compression have been determined and the relationship between those properties was studied. Direct tensile tests were applied to measure those properties in tension. The relationship of creep in tension and compression was determined based on the measurement of creep at similar stress and similar stress/strength ratio. It is found that concrete deforms more in tension than in compression. Except for concrete with a higher water/cement ratio, the use of pulverised fuel ash, ground granulated blast furnace slag, superplasticizer and shrinkage reducing admixture has no effect on strength. However, they affect creep and shrinkage of concrete.

Housing projects in Colombia mostly consist in multiple-family (apartment) or single-family (house) housing. The former restricts the possibility of spatial expansion and its built-up area is usually smaller than that of their former type of house (informal). In the case of single-family housing (houses), expansions made by the owner — which are proportional to the economic resources that are available to him (progressive housing) — are assumed not to adhere to the plans and instructions of the basic unit constructor under the provisions of seismic regulations. This paper proposes an implosive, single-family social interest housing model that delivers a fully closed, double height structure with the minimum room facilities. Progressive development consists in the staircase structure and mezzanine in a lightweight and low cost material in order to facilitate and speed up the construction process, significantly decreasing the house’s risk of collapse in the event of a natural event. I...

Pembuatan Komposit Plafon memiliki acuan mutu berupa kuat tekan, kuat tarik, dan kuat lentur, hal ini mengacu pada SNI 03-2105. Kekuatan tekan merupakan kapasitas dari suatu bahan atau struktur dalam menahan beban yang akan mengurangi ukurannya. Sebaliknya kekuatan Tarik adalah tegangan maksimum yang bias ditahan olehsebuah bahan ketika diregangkan atau ditarik, sebelum bahan tersebut patah. Penelitian ini diharapkan dapatm enentukan komposisi terbaik dengan metode eksperimen dari variasi komposisi bahan. Benda uji yang dibuat terbuat dari semen dan agregat, dengan agregat campuran dari serat tebudan styrofoam. Variasi yang digunakan adalah 60%, 70%, 80%, 90% Semen dari total massa benda uji. Serta variasi dari agregat yaitu antara SeratTebu dan Styrofoam 60:40, 70:30, 80:20, dan 90:10. Analisa kuat tekan, kuat tarik, dan kuat lentur dilakukan setelah umur 14 hari. Rasio perbandingan agregat (styrofoam dan serat tebu) yang optimal sebagai plafon komposit, mempunyai kelebihan masing ...

A new approach that adopts the use of fuzzy adaptive resonance theory (ART) neural network in estimating high‐performance concrete (HPC) mix proportion from experimental data is devised. The proposed model receives a set of desired concrete performances, searches for a set of mix proportions that is near to the desired concrete performances, classifies the mix proportions into clusters, measures the similarity between performances of deduced clusters with desired performances, and deduces a mix proportion. The proposed model was used to estimate the mix proportions of five batches of concrete based on the performance criteria of 7th and 28th day compressive strengths. The generated mix proportions were used in an experimental work and the errors were within 13% for 7th compressive strength; and 7% for the 28th day compressive strength, signifying the reliability of the fuzzy ART‐based model in estimating the mix proportion of HPC. This article contributes to an alternative method of...

Self-compacting concrete offers significant advantages in infrastructure projects, but its application in specific regions such as Juní n has not yet been widely studied. The research evaluates the design of self-compacting concrete with microsilica and plasticizer, focusing on its workability, cost and strength. Using a mix with type I cement, 5-10% silica fume and SikaCem, workability and strength tests are performed. The purpose is to determine the economic feasibility and technical advantages of self-compacting concrete compared to conventional concrete. The results show excellent flowability and passability, with a flow time in the V-funnel of 10.8 seconds and a blocking coefficient of 0.9, complying with regulations. Strength tests reveal values of 407.3, 426.5 and 437.9 kg/cm² at 7, 15 and 28 days. Although the initial cost is higher ($120/m³), the cost-benefit analysis highlights a 17% reduction in construction time, with savings in labor and maintenance, and greater durability. The cost/benefit ratio of 1.2061 indicates that self-compacting concrete is economically favorable and efficient for complex construction. The conclusions highlight that, although the initial cost of self-compacting concrete is higher, the long-term savings and advantages in terms of quality and durability justify its adoption. It presents a better understanding of the economic and technical impacts of self-compacting concrete, providing a solid basis for its implementation in infrastructure projects in the region by considering local variables in the analysis, which offers a contextualized perspective relevant to the specific conditions of the area. This study underscores the importance of innovating in construction materials to improve efficiency and sustainability in the industry.

The objective of this paper is to reduce the use of expensive chemical admixtures in construction materials and to increase the use of natural and sustainable materials for the users' health and well-being. The gum produced from Acacia trees is chosen in this study, crushed into a fine powder, and added with cement as a dry mix to examine its effects on the properties of concrete. Acacia trees are the most commonly grown in Middle East Northern Africa (MENA) and are known as Arabic Gum (AG). The effect of Arabic gum is studied on mortar cubes of size 5cm x 5cm with 1% and 2% of Arabic gum with respect to the weight of the cement and on concrete cubes of size 15cm x 15cm with 1% and 2% of Arabic gum with respect to the weight of the cement. It is found that mortar cubes with 1% AG perform better than cubes with 2% AG. However, in concrete cubes, 2% AG perform better than conventional cubes and 1% AG. The compressive strength of 2% AG is higher by 3% than conventional concrete. It is found that concrete cube with 2% AG shows high workability and less voids compared to conventional concrete cubes. Concrete cube with 2% AG enhances the compressive strength of concrete and hence it is recommended to be used for load bearing applications and due to low density and self-weight, it is also recommended to be used in non-load bearing applications.

This paper presents results of the optimal dosage levels of polycarboxylate-based (PSP) (0.4 and 0.8%) and naphthalene-based (NSP) (0.8 and 1.6%) super plasticizers and different water to binder (w/b) ratios (0.4 and 0.45 ) that produce an adequate balance between strength and workability for concrete containing nano-SiO2 (NS) of 1%, 2%, and 3% as cement replacement. These results indicate that For two types super plasticizers mixes. Increasing the w/c ratio from 0.40 to 0.45 increased the slump of all mixes. Either those containing polycarboxylate or naphthalene sulphonate super plasticizer or the control mixes. For polycarboxylate super plasticizer mixes. Decreasing the w/c ratio from 0.45 to 0.40 increased the compressive strength of all mixes. Either those containing polycarboxylate super plasticizer. For naphthalene sulphonate super plasticizer mixes. Increasing the w/c ratio from 0.40 to 0.45 increased the compressive strength of all mixes. Either those containing 0.8 % naphthalene super plasticizer or the control mixes. While decreasing the w/c ratio from 0.45 to 0.40 increased the compressive strength of all mixes. Either those containing 1.6 % naphthalene sulphonate super plasticizer. the use of (1.6 %) sulphonated naphthalene super plasticizer (NSP) with 0.4 w/c ratio reached a gain in strength equivalent to the use of (0.8 %) polycarboxylic super plasticizer (PSP) for mix containing 3 % nano silica . the use of (1.6 %) naphthalene super plasticizer (NSP) with 0.45 w/c ratio reached a gain in strength equivalent to the use of (0.8 %) polycarboxylic super plasticizer (PSP) for mix containing 2 % nano silica.

Corrosion of steel reinforcement is one of the most prevalent causes of reinforced concrete (RC) structures deterioration in chloride-contaminated environments. As a result, evaluating the impact of any possible corrosion-induced damages to reinforced concrete bridges strongly affects management decisions: such as inspection, maintenance and repair actions. The corrosion propagation phase is a significant factor in the service life of reinforced concrete structures and thus, it is requires appropriate attention. Various models have been developed to simulate and/or predict the propagation phase. This paper proposes that a method in which a reliability framework is developed to assess the durability of reinforced concrete structures under corrosion inmarine environments functions better. The main concern of this study is chloride-induced corrosions.In due regard, serviceability and ultimate limit states of the structure are also taken into account. Subsequently, the proposed method is employed to review the existing models for prediction of corrosion propagation.

In the case of reinforced concrete structures, the complex nature of the effects of the aggressive environment on concrete structures, as well as ensuring a long service life, also requires additional measures to maintain and prevent degradation/deterioration risks. These degradations/deteriorations are based on durability reasons. In this paper, an experimental program for assessing physical and mechanical characteristics (visual inspection of the structure, nondestructive and destructive testing methods) have been presented in the case of a reinforced concrete structure. On the basis of the investigations carried out and the numerical results obtained, the level of degradation/deterioration was estimated and some technical interventions were proposed at the level of the structural elements.

Fabric-cast concrete involves casting concrete in forms made with flexible formwork. This provides the potential to produce forms that are both structurally efficient and architecturally exciting in a relatively inexpensive and practical manner. By careful shaping of the fabric it is possible to produce complex shapes that would otherwise be difficult and expensive to produce using conventional formwork systems. This book contains six essays that describe the collaboration between the Universities of Edinburgh and East London, together with the Centre for Architectural and Structural Technology (CAST) at the University of Manitoba, in their detailed and practical research into concrete casting and formwork. Richly illustrated with photographs and diagrams and containing new and innovative research this book offers the architect, engineer and student inspiration and technical guidance in this re-emerging material. Published (publisher's copy) Peer Reviewed

Ultra High Strength Concrete (UHSC) merupakan terobosan yang sedang dikembangkan dalam beberapa dekade terakhir ini. UHSC memiliki beberapa kelebihan dibandingkan Normal Strength Concrete (NSC), yaitu beton UHSC memiliki ketahanan yang lebih baik terhadap asam, kebakaran, maupun ketahanan jangka panjang. Pada tahun 2010, di Indonesia telah dapat dibuat beton UHSC dengan kekuatan mencapai 140 MPa dengan memanfaatkan material lokal dengan ukuran yang sangat halus walaupun masih di laboratorium. Dalam penelitian ini akan dicari mix design yang dapat mencapai kuat tekan UHSC, pengaruh steam curing, penambahan steel fibres, dan proses vacuum dalam pembuatan UHSC. Pencarian mix design dilakukan terebih dahulu sebelum melakukan penelitian yang lain. Kuat tekan maksimum yang dicapai adalah sebesar 115 MPa pada umur 28 hari. Perlakuan steam curing memberikan pengaruh pada kuat tekan awal dan dengan melakukan proses vacuum dalam proses pemadatan benda uji tidak memberikan pengaruh dalam kekuatan. Penambahan steel fibres memberikan pengaruh yang baik dari segi ketahan dalam mengatasi keruntuhan yang getas. KATA KUNCI: ultra high strength concrete, UHSC, steam curing, steel fibres, vacuum. Ultra High Strength Concrete (UHSC) merupakan terobosan yang sedang dikembangkan dalam beberapa dekade terakhir ini. UHSC memiliki beberapa kelebihan dibandingkan Normal Strength Concrete (NSC), yaitu beton UHSC memiliki durability yang lebih baik terhadap asam, kebakaran, maupun ketahanan jangka panjang. Penentuan komposisi yang optimum dari setiap material penyusun beton UHSC sangat diperlukan, baik dari aggregat halus, semen, supplementary cement material, air, dan metode-metode yang akan digunakan selama proses pembuatan.

Maintaining the health and reliability of civil facilities is of strategic importance. In highway engineering, pavement cracking impairs the road service and travel comfort level,while structure cracking can cause catastrophic damage. Microcapsule-based self-healing materials offer solutions to auto-recovery micro-cracks and maintain structural health. Such a solution has become available by laboratory synthesis and proved effective in addressing the cracking problem during long-term mechanical, thermal, and hydraulic conditions.However, full-scale applications of this technique are not prevalent, showing its potential limitations in highway engineering. Crack healing in highways is a big topic, therefore, this
review has two insertion points. We focus on the cracking issues on two specific materials:asphalt and concrete, which account for the vast majority of all the materials used in pavement and structures in highways. Instead of the laboratory studies, we pay more attention to the practical applications, the meaning of healing performance, and the adverse effects of microcapsules to the main structural components (i.e., tunnel lining, bridge piers and beams) and pavement in highways. The practical significance of self-healing materials in highway projects was discussed from the three aspects: strength, durability, and stress redistribution. The difficulty in applying this new technique is also discussed from an economic perspective. For future-proofing, a material evaluation system that fits the load condition is required.

The sudden increase in industrialization has reduced the availability of natural building materials and triggered the growing awareness of sustainable practices within the construction industry. The study presented here deals with marble powder, which is one of the by-products obtained from the marble industry, as a cement replacement in concrete mixtures. The main aims will be to investigate the impact of marble powder waste materials on the mechanical properties of concrete and to promote the recycling of various industrial wastes for environmental sustainability. Material testing was conducted with the levels of substitution of marble powder for cement ranging from 0% to 50%, and the resulting concrete was evaluated for compressive and tensile strength over different curing periods. The results show that concrete compressive strength and tensile strength are most efficiently improved when marble powder replacement is up to 10-15%, attaining its full potential after 28 days. Beyond this replacement level of 15%, the mechanical properties decrease, suggesting that higher substitution levels may not be effective. This paper consolidates findings, provides a novel comparative analysis, and addresses key challenges regarding the use of marble powder, providing room for the future industrial development of supplementary cementitious materials (SCMs), eventually leading to sustainability in the construction sector.

The traditional method of construction is to support slab by beam and beam by columns it is known as beam slab load transfer construction technique, but the modern technique developed is gaining more popularity as it can provide better aesthetical appearance compared to traditional method for shopping mall, offices, warehouses, public community hall, theatres etc. By adopting modern techniques construction work can be carried out faster with economic consideration. The aim of project is to determine the most economical slab between flat slab and grid slab. To study related design & analysis of flat slab and grid slab with conditions where it is preferable with advantages & disadvantages of providing flat slab and grid slab. At last we are going to give cost estimation graph with comparison of flat slab and grid slab for the plan dimension of 30m x 30m. Rates will be taken according to government schedule.

In this research, the use of clay bearing diatomites from Kütahya-Alayunt region in cement production as puzzolanic materials was investigated. Cements were produced by adding clay bearing dioatomites to the cement body by 5%, 10%, and 20% and grinding them together with clinker materials. After the tests, it was found that 10% and 20% clayed diatomite addition could be used in 42.5-class cement production. İf the strength of portland cement clinker was about 50 N/mm 2 . By utilizing this material, less clinker4 produced at 1450 o C will be needed which means lower emission rates causing environmental pollutions and a special type of cement can be obtained by using diatomite for lower specific gravity, heat and noise insulation

A four-cylinder pneumatic motor is proposed and analyzed as an expansion machine to be used in a compressed-air energy storage system. The motor uses a combination of displacement work at constant pressure followed by a sequence of expansion of the air. The four double-acting linear cylinders form two groups of chambers, each with one chamber for the constant pressure displacement work and three chambers in which the air is expanded. The operation of the system and especially the allocation of the functions were analyzed, and the system was simulated with the produced forces given by the cylinders to the torque generated from the crankshaft. A demonstration set-up was also realized with a specific motivation which was to show how demonstration objects could be realized with very limited infrastructure. Finally, the motor energetic efficiency was calculated.

Dalam pembuatan benda uji metode yang digunakan yaitu Metode SNI , dengan kuat tekan rencana K-175 . Semen yang digunakan adalah semen PCC . Benda uji yang dibuat berbentuk kubus 5x5x5 cm. Pengujianbenda uji meliputi uji kuat tekan , uji modulus elastisitas , dan uji permeabilitas. Dari hasil penelitian cangkang kerang dapat digunakan sebagai alternatif agragat halus pada mortar. Kekuatan tekan karakteristik mortar normal sebesar 366,48 kg/cm 2 . Peningkatan kuat tekan karakteristik umur 28 hari terjadi pada persentase cangkang 15% (CK-15)  sebesar 426,48 kg/cm 2 , persentase cangkang 30% (CK-30) sebesar 405,98 kg/cm 2 , persentase cangkang 45% (CK-45) sebesar 388,32 kg/cm 2 , dan persentase cangkang 75% (CK-75) sebesar 380,19 kg/cm 2 . Sedangkan pada persentase cangkang 100% (CK-100) terjadi penurunan kuat tekan karakteristik sebesar 312,66 kg/cm 2 . Subtitusi cangkang kerang yang paling baik adalah subtitusi pasir dengan cangkang kerang sebesar 15% (CK-15). Modulus elastisitas(Ec)...

Penelitian tentang beton terus berkembang seiring dengan perkembangan zaman dan teknologi. Salah satunya adalah penelitian tentang beton ringan. Beton ringan sangat banyak dikembangkan karena manfaatnya yang dapat mengurangi berat sendiri suatu bangunan, sehingga efek gempa terhadap bangunan dapat diminimalisir. Salah satu cara membuat beton ringan adalah dengan mengganti agregat kasar dengan batu apung. Pada penelitian ini digunakan dua variabel bebas yaitu variasi penambahan serat bambu dan pelapisan batu apung. Variasi penambahan serat bambu yang digunakan yaitu 0%, 1%, 1.2%, dan 1.4% terhadap berat semen sedangkan batu apung yang digunakan adalah batu apung tanpa pelapisan dan batu apung dengan pelapisan. Benda uji yang digunakan memiliki dimensi 15 x 15 x 60 cm untuk selanjutnya dilakukan pengujian lentur dengan beban dua titik di 1/3 bentang tengah. Berdasarkan hasil analisis varian satu arah, didapatkan F hitung 0.490 dan F tabel 3.24 untuk pengaruh variasi penambahan serat p...

Pembangunan infrastruktur merupakan kebutuhan dasar dalam pertumbuhan ekonomi suatu negara.Berkembangnya infrastruktur pembangunan di Indonesia pasti akan memiliki dampak yang kurang baik bagi lingkungan. Salah satu dampaknyayaitu produksi material baja. Upaya untuk mengurangi dampak yang kurang baik tersebut dengan memanfaat limbah baja yang dijadikan bahan substitusi semen. Pada penelitian ini, benda uji yang digunakan yaitu silinder dengan diameter 15 cm dan tinggi 30 cm. Variasi yang digunakan yaitu, komposisi semen slag 0%, 10%, 40%, dan 70%, umur 7 hari, 28 hari, dan 56 hari, mutu Beton K-350 dan K-275, dan FAS 0,3 dan 0,4 . Pada pengujian kuat tarik belah alat yang yang digunakan yaitu Compression Test Machine. Dari hasil penelitian ini yang didapatkan adalah semua variasi yang digunakan berpengaruh terhadap nilai kuat tarik belah beton. pengaruh dari semua variasi tersebut terdapat peningkatan nilai kuat tarik belah beton. Nilai kuat tarik belah beton yang meningkat dari var...

The inability of tires to biodegrade harms the environment and the entire ecosystem. Sometimes, discarding or keeping these old tyres in one location can turn them into a breeding ground for germs, insects, and mosquitoes, leading to infectious illnesses. Wood waste is compressed into crumb rubber as a powder using hot pressing. The scrap wood and crumb rubber used to create the woodrubber composite have good mechanical qualities. After completing the tensile, tear, and thermal testing, it was discovered that the tensile strength is of the commercial material is 7.848 MPa, which is closer to that of virgin rubber (10 MPa). Over 120 N is Known to be the yield/break force. The yield elongation and %age elongation are determined to be close to 180%, similar to those of virgin rubber. In addition to its mechanical characteristics, it exhibits water absorption rates closer to 1 part in a thousand cycles and extremely little chemical erosion, similar to virgin rubber. The manufactured recycled crumb rubber is also suitable for commercial applications, including flooring, sound insulation, heavy-duty performance, and vibration absorption due to the aforementioned qualities.

After several disastrous building collapses, concepts such as progressive collapse and robustness of structures have been reflected in many research papers and resulted in new codes and guidelines available in Europe and in the United States. The collapse of an entire structure or an essential part of it that is disproportionately large compared to the initiating local damage is considered a progressive collapse. In addition to the design guidelines, the mentioned standards provide provisions for the progressive collapse analysis of newly designed and existing structures. Therefor this study concerned with collapse behaviour of RCC building and various recent studies associated with it.

La apertura de la unidad de diálisis peritoneal se efectuó en abril de 2008. Con la fi nalidad de agilizar y estandarizar el procedimiento a seguir, se diseñó un plan estratégico de enfermería para la creación de nuestra unidad de diálisis peritoneal. Este trabajo pretende revelar la metodología utilizada para crear nuestra unidad de diálisis peritoneal y tras 3 años y medio de prestación de servicios, plasmar los resultados asistenciales obtenidos.

It is the objective of this project is to investigate the mechanical and chemical behaviour of new concrete type obtained by adding aluminium dross which is an impure aluminium mixture that results from metals melting and mixing with flux. The main advantage of this type of concrete over the conventional ones is the reduction in the quantity of raw materials. The results of this study indicate that aluminium dross can be used as an ingredient in the range of certain limits to improve expanded concrete/mortar and to improve the corrosion resistivity of concrete/mortar. The most interesting finding was that aluminium dross accelerates the setting time of concrete/mortar. Because of these findings it is suggested that aluminium slag added concrete/mortar may be used in the manufacturing of buildings subfloors, panels, blocks etc.

This study investigates the utilization of slag and fly ash (FA) as alternative cementitious binder. Combination of 60% slag and 40% FA was used as new binder. In addition, for activation of slag and FA, sodium hydroxide and calcium hydroxide was used as a chemical activator by 5% weight of the binder, separately. Water to binder and sand to binder ratios was kept 0.55 and 3 in mortar preparation, respectively. Superplasticizer was used by 2.5% of the weight of binder to get reasonable flow for casting. Physical and chemical properties of slag and FA, and fresh and hardened properties of mortar of the new binder were determined and compared with that of OPC. New binder which was activated by sodium hydroxide sets early than OPC. Mortar as produced from new binder with sodium hydroxide shows 12. 02, 18.15 and 26.20MPa compressive strength at 7, 14 and 28 days, respectively; while OPC mortar achieved 25.67, 30.08 and 35.78MPa compressive strength at the same ages and conditions. Sodium hydroxide exhibits greater activation performance than that of calcium hydroxide. Thus, depending on the preliminary test results it can be concluded that, with the presence of chemical activator, slag and FA can be used together as an alternative of OPC.

This paper presents results of an experimental study about partial substitution of granulated blast-furnace slag (GBFS) as fine aggregate in production of concrete paving blocks and kerbs. GBFS is replaced sand for different GBFS/sand ratios in concrete during production of kerb and paving block specimens. Some tests orienting towards strength and durability were applied on these specimens including control specimens that are produced with normal concrete. Then, the results of tested properties of GBFS-replaced specimens and control specimens were compared. GBFS decreases the compressive strength of paving blocks and kerbs according to the results. However, some durability properties which are more important than strength for these elements are improved with GBFS replacement. The most improved property was abrasion resistance. It is concluded that it is feasible to use GBFS in paving block and kerb production with an optimum replacement ratio for these specimens.