Concrete Building Blocks Research Articles

Failure Analysis of Cast Iron Housing Unit of Ucf-216 Ball Bearing Used in a Fully Automatic Concrete Building Block Machine

One of the most common problems faced by briquette machine users in the industry is the failure of the cast iron housing unit of the UCF-216 bearings, to which the main shaft of the briquette machine is attached. In this study, the failure mechanism of a cast iron housing unit of a UCF-216 bearing broken during operation in a briquette machine was analysed in order to develop a solution to the problem. Failure was occurring in the bolt hole areas of the housing unit. First of all, spectral analysis was performed and it was determined that the housing unit was grey cast iron. Then, the macrostructures of both unused and damaged housing units were examined. Some casting defects were detected in the bolt hole areas of the unused housing unit. It was also learned that during the assembly of the UCF-216 to the briquette machine, no torque meter was used while the bolts were tightened. In order to understand the effect of possible overtightening of the bolts, the system was modelled as a 3D solid. This model was exported to the finite element software and different bolt pretensions were applied considering the stresses created by the bolt tightening forces on the housing unit. As a result, it was understood that if the ratio of the stress caused by the axial bolt tightening force in the UCF-216 bearing unit to the yield stress of the UCF-216 housing unit is above 50%, fatigue failure will occur.

Experimental investigation of eco-friendly building blocks utilizing coconut shells

In the construction of structures, cement is commonly utilized as a construction material. The high cost of conventional building materials has a significant impact on the structure's economy. Synthetic lightweight aggregate manufactured from environmental trash is a potential new source of structural aggregate material, as concerns about the over use of natural aggregates develop. As more natural resources from the earth's surface are used, they are becoming deficient. Alccofine is a new generation micro fine concrete material for high Strength which is important in respect of workability as well as strength. As a result, the coconut shell is being investigated as a partial substitute for coarse aggregate in building blocks then cast it. The compressive strength, slump, and density of concrete are all evaluated. In the concrete building blocks, the replacement of cement with an Alccofine by 5% and the replacement of coarse aggregate with coconut shell by 0%, 50%, 100%. As the percentage of replacement increased, it was seen that the slump was getting worse. The density also drops as the proportion of replacement rises. The compressive strength is demonstrated to decline as the percentage replacement increases.

Manufacture of Load Bearing Concrete Masonry Units Using Waste Demolishing Material

The presence of construction wastes such as clay bricks, glass, wood, plastic, and others in large quantities causes serious environmental problems in the world. Where these wastes can be used to preserve the natural resources used in construction and reduce the impact of this problem on the environment, it also works to reduce the problem of high loads of concrete blocks. Clay bricks aggregate (AB) can be recycled as coarse aggregate and replaced with volumetric proportions of coarse aggregate by ( 5% and 10%), as well as the use of clay brick powder (PB) by replacing its weight of cement (5% and 10%) and reduced in the manufacture of concrete blocks (blocks). Four mixtures will be prepared and tested to learn how to reuse the brick coarse aggregate ACB and PB powder brick as substitute materials for producing concrete blocks, use the water spray method to treat concrete building blocks (blocks) and check the Dimensions and compressive strength, and absorption.

Life cycle energy analysis of houses incorporating conventional and alternative masonry units

ABSTRACT The use of alternative masonry units and technologies in traditional masonry work could reduce the life cycle energy of buildings. This study investigates the life cycle energy assessment of houses constructed using concrete blocks, eco-bricks and polymer bricks to evaluate the impacts of masonry units on the life cycle energy of buildings. Three bungalows of approximately 110 m2 each, having the same geometry but different types of wall materials, namely eco-bricks, polymer bricks, and concrete blocks, were used for the analysis. The study found embodied manufacturing energy of 0.346 MJ/kg for eco-bricks and 0.518 MJ/kg for polymer bricks. Approximately 85-86% of the total life cycle energy constitutes the operational phase energy. The polymer brick and eco-brick buildings had the least embodied construction energy of 14% of the total life cycle energy. The life cycle energy of concrete block buildings was 17.547 GJ/m2 at 50 years of service life. Buildings made of polymer bricks and eco-bricks had lower life cycle energy than the concrete block building. The study suggests a prudent selection of building materials by developers and construction professionals based on life cycle energy assessment to reduce the energy consumption of the building sector. Although the study focus is limited to eco-bricks, polymer bricks, and concrete blocks as masonry units in the Nigerian construction context, the method employed in the study is applicable to the energy analysis of other construction materials and geographical locations.

Managing post-conflict demolition wastes in Gaza Strip: a case study on May 2021 conflict

Gaza Strip is considered as one of the armed conflicts prone areas in Middle East. Several intensive conflicts occurred in Gaza Strip in 2008, 2012, 2014 and 2021. These conflicts caused massive destroying the infrastructures, facilities, and buildings, which affected all services and activities in Gaza Strip. One of the major post-conflict issues in Gaza strip is the management of resulted demolition waste including its removal, sorting, recycling, and material recovery. In May 2021, over than 370,000 tons of demolition waste composed of rubbles and debris was generated during 11 days of armed conflict. The accumulated previous experience of rubbles and debris removal and recycling in Gaza Strip supported to perform a quick management approach for safe removal of the post-conflict demolition waste and reuse/recycle the resulted waste materials in various applications. The sorting and transporting process of concreate and non-concreate rubble elements of the waste were carried out in cooperation between local and international agencies as emergency recovery-funded projects. The most proportion of rubbles are concrete aggregates, thus, the material recovery was conducted through crushing process for concrete rubbles and then reusing it for road rehabilitation or producing concrete building blocks. The large concrete blocks reused to be placed for shoreline protection for specific area along Gaza beach. The recycling of post-conflict demolition waste management projects in Gaza Strip brought economic and social benefits through the reuse and recycle of resources and creation of job opportunities. In conclusion, although the post-conflict demolition waste management is quite different from municipal/industrial waste management in Gaza Strip, it is conducted through applying similar techniques of disaster waste management in waste removal, and those of construction and demolition (C&D) waste management in sorting, crushing, and sieving for recycling.

PENGARUH SUBSTITUSI CANGKANG KEMIRI PADA SEBAGIAN AGREGAT HALUS UNTUK BETON K-250 TERHADAP KUAT TEKAN

Concrete is one of the most widely used materials in the construction industry. Concrete building blocks are materials that are widely found in nature, including sand and gravel and cement constituents. Candlenut shell is one of the additives or substitutes for aggregate which has recently been used. began to investigate the impact of its use on the mixture in concrete. The use of candlenut shells can be treated as a substitute for coarse or fine aggregate depending on the size of the pecan shell grains used. and to determine the optimum compressive strength of concrete by mixing candlenut shells as a partial substitute for fine aggregate with a percentage of 0%, 10%, 20%o and 30% of the weight of the fine aggregate. The research method is testing the compressive strength of concrete samples by carrying out laboratory test result. From the results of the concrete experiments that have been carried out and the data that has been obtained with the normal quality of fc 20.75 Mpa concrete and concrete with candlenut shell substitution for coarse aggregate in a mixture of 10%, 20%, and 30%, there are several conclusions, namely the age of concrete is 7, 14.28 days of mixed concrete of 10%, 20%, and 30% of the compressive strength experienced a decrease in the normal concrete compressive strength in every variation of the percentage. The results of the research of normal concrete and candlenut shell mixture on normal concrete 7,14,28 days are 10,74 MPa,13,86 MPa. 14.42 MPa, in 10% candlenut shell mixture 7.14.28 days which is 7.35 MPa. 10.75 MPa. 11.03 MPa, in the mixture of 20%% candlenut shells 7.14.28 days, namely 6.19 MPa, S.48 MPa 9.33 MPa, and in the mixture of 30%% candlenut shells, which is 6.79 MPa. 7,36 MPa, 8,77 Mpa/ Use candlenut shell for partial substitution of fine aggregate in concrete cannot be used as a material as a constituent of concrete.

Waterpower and Allegan, Michigan

Waterpower and Allegan, Michigan Patrick R. Hudson On an out-of-the-way back street in the city of Allegan stands a remnant of Allegan's, and indeed Michigan's, industrial heritage. Enter Allegan from the southeast on M-89, turn on Second Street using the "Old Iron Bridge" to cross the Kalamazoo River, and follow Second Street to its end at Water Street. There, instead of turning left toward the business district, turn right and follow the signs to the mill district. Crossing the bridge, look to the right to find the Allegan dam. The bridge runs over what is left of the old millrace. Look to the left across the mill pond to find a small concrete block building on the spot where Allegan's industrial and civic origins began. The Origins of the City In 1837, Michigan became a state. The development of these forested peninsulas from territory to statehood was delayed for over a decade by Ohio's claims on the port of Toledo, originally within the territorial boundary of Michigan. For the new state legislature, its greatest challenge was overcoming the early characterizations—by General Duncan McArthur and Edward Tiffin, Surveyor General of the United States, among others—of Michigan as a mosquito-infested swamp.1 The publication of John Farmer's gazetteer Farmer's Guide to Michigan in 1830 was the first of a number of documents refuting previous detrimental characterizations of the state. It became one of the catalysts for the migration of New Englanders and upstate New Yorkers to the Michigan territory.2 This migration, characterized as "Michigan Fever," was a movement of communities rather than the "rugged individuals" of common myth. These groups generally included skilled tradesmen, such as millwrights, masons, carpenters, bakers, butchers, and seamstresses, as well as farmers and lumbermen. In many cases, a surveyor would be sent [End Page 105] out to find the type of land the community desired, then a company would be formed to purchase the land and organize development. This type of company founded the village of Allegan. A group of businessmen, known as the Boston Company, hired a surveyor to lay out an industrial town and seat of government for the new county of Allegan. The economic life of this community would be centered around a millrace providing waterpower for industries. The company was initially successful. Within two years, Allegan was incorporated as a village. The village's near central location allowed Allegan to claim the county seat. Waterpower was the cheapest, most abundant source of energy available until after the Civil War, when coal-powered steam engines began to replace waterpower.3 The siting of settlements at locations suitable for a dam and watermill was typical of settlement patterns during the 1830s. The nineteenth century was a time when the general impression in both Europe and Anglo-America was that the individual could use science and industry to overcome nature. The religious fervor of the Second Great Awakening fed the common belief that mankind held a God-given right to remake the natural world for its use and prosperity.4 As important as waterpower, technology, and the physical setting were for any location, transportation connections for Allegan became a limitation for future development. The ancient aboriginal trail to the north and south in western Michigan ran ten miles east of the settlement, and the Kalamazoo River, running through the village site, did not have enough depth year-round to support river transport for heavy cargo to or from Lake Michigan.5 Michigan's territorial government (from 1827-1835) and state legislature (from 1835-1844) experimented with various means of funding roads. None of the territorial roads reached Allegan County. The 1835 state constitution provided for transportation improvements, but the Panic of 1837 put an end to state funding. This was followed in 1844 by the Plank Road experiment, which amounted to licensing private toll roads but proved to be a failure due to the very short lifespan of such roads. Michigan's 1850 constitution turned the question of road funding over to local townships and allowed for conscript labor to construct and maintain such roads. This method failed to provide for any...

Performance analysis of concrete block integrated with PCM for thermal management

Abstract Deployment of phase change materials in buildings for thermal management had enthralled researchers for the past two decades owing to high energy storage per unit volume and isothermal action during phase change. This paper presents an experimental investigation of phase change materials being integrated in layers within concrete block for thermal management. Two identical concrete building blocks are constructed and their thermal performance was evaluated with and without integration of PCM under natural environment. Thermal analysis results reveal that PCM integrated concrete block exhibited less temperature fluctuations than block without PCM. Results reveal that maximum air temperature was reduced up to 3 °C was observed in the concrete block with PCM, compared to block without PCM. Also, addition of PCM results in flattened temperature profile within concrete block. Further, the effect of varying PCM thickness was also evaluated and results reveal that thickness of 12 mm was optimum for the employed concrete block space and above which no significant change was found.

Manufacture of structural blocks of concrete with waste tire rubbers

The construction industry is a major consumer of natural resources and is directly related to the technological and industrial growth of the country. Various segments of society have turned to the concepts of sustainability, seeking alternatives to reduce the impacts caused by the use, in most cases, indefinite of raw material and by the large volume of waste generated, include the waste tire rubber. The use of waste as raw materials in construction, as well as minimize the extraction of natural resources, such as sand and gravel, can also reduce the accumulation of these tailings in urban areas, making it also a technical solution bringing benefits the buildings as: reduced density, better drainage and property improvement in thermal and acoustic insulation. The present work aims to demonstrate the use of waste tire rubber as aggregate in concrete building blocks, showing the relationship between the term sustainability and your application, viaare the production of bodies of evidence produced in the laboratory by assessing their physical and mechanical properties.

The Dutch Cybersecurity Landscape: From Cyber ‘Air Castles’ to Concrete Building Blocks

Since 2010, the Netherlands has led a wide range of initiatives promoting cyber-security and stability. The government currently engages with variety of stakeholders – including the private sector, civil society, state actors, and intergovernmental organizations – across multiple fora and organizations. Rather than being a passive participant, the Netherlands has been a catalyst, driving change in the field of cyber security both domestically and internationally. Yet, the challenge which lies ahead for the Dutch government is to make sure their cyber efforts as a whole will become greater than the sum of its parts. It will require increased coordination and collaboration across initiatives to turn the current patchwork into a synergistic endeavor.

Mechanical properties, durability, and life-cycle assessment of concrete building blocks incorporating recycled concrete aggregates

This paper aims to explore the possible use of recycled concrete aggregates (RCAs) to produce concrete building blocks. Laboratory test and plant trial were carried out to manufacture concrete building blocks incorporating 75% RCAs. A series of tests were conducted to investigate the mechanical and durability properties of the recycled aggregate concrete (RAC) blocks. The compression and shear performances of masonry prisms built with RAC blocks and conventional mortars were experimentally studied too. Furthermore, the environmental impact of RAC blocks was studied using life-cycle assessment (LCA) method. Five different environmental impact categories (i.e., GWP, AP, EP, HTP, POCP) are calculated and comparatively analyzed. The effect of RCAs on the mechanical and durability properties, as well as the environmental impact of RAC blocks was investigated. The test results indicate that the incorporation of RCAs slightly declined the compressive strength and impaired the durability of the concrete blocks. Nevertheless, concrete building blocks incorporating 75% RCAs satisfied the strength, drying shrinkage and freeze-thaw resistance requirements for concrete building blocks specified by Chinese standard. The compressive and shear performances of masonry prisms constructed with RAC blocks are similar to those of conventional concrete masonry. RAC blocks have less environmental impact compared to normal concrete blocks. It is feasible to use RCAs to manufacture concrete building blocks along with environmental benefits. The use of RAC blocks plays a key role in ending the building life cycle and will improve the sustainable development of masonry structures.

Strength properties of concrete blocks with Sand Manufacture Sludge as partial replacement to fine aggregate

The proper disposal of Sand Manufacture Sludge(SMS) from the site is a major problem faced by most of the stone crushing units. SMS when dried is in the form of a fine powder. Due to its sticky nature and time taken to dry, transporting this material is very tedious. Hence it necessitates for finding a solution for the usage at the site itself, in the form of a construction material. This study focuses on replacing M Sand with SMS for the development of concrete building blocks. The study evaluates the effectiveness of use of this waste SMS in manufacturing concrete building blocks and estimating its strength properties, keeping a constant workability throughout. The strength, impact and abrasion properties of the concrete blocks are studied and compared with the conventional blocks and shows good agreement

Alien plant species establishment is associated with reduced soil acidity in the vicinity of concrete block structures1,2

Abstract We hypothesized that in the oligotrophic, acid soils of the New Jersey Pine Barrens, where native diversity and invasability appear to be low, the weathering of concrete block construction material over time has reduced resistance to plant species' invasion by reducing soil acidity. We also sought to determine whether alien species' success in disturbed Pine Barrens soil differs from that of the non–Pine Barrens North American plant species whose presence in the region is associated with anthropogenic soil disturbance. In the field, species richness of native Pine Barrens species, non–Pine Barrens species, and alien species was determined along with current-year aboveground biomass production and soil pH along transects extending from concrete block buildings and from paired control transects without concrete block buildings. Soil inorganic nitrogen was measured near and far from buildings. Additionally, a pot study using native soil amended with ground concrete was conducted to determine its eff...

Study of preparation for autoclaved aerated concrete with low-silicaironore tailings

To investigate how properties will impact on by the fineness and content of low-silica iron ore tailings that used as the main raw material of autoclaved aerated concrete (AAC), testing methods such as mechanical properties testing, XRD, and FE-SEM were used in this research. Results shows that the decreased fineness of iron ore tailingsmake hydration reactions occur more quickly, with more hydration products being generated and the product’s compressive strength increases. However, it may generate extra fine residues of unreacted raw materials that would be difficult to form good foam structures, so that the compressive strength decreases. A higher proportion of iron ore tailings helps increase the amount of tobermorite that turns from a needle or schistose shape to a short fibrous shape. The tobermorite then forms a network structure by interweaving with each other. In this respect, the product’s compressive strength is raised. On the other hand, if there are too much content of iron ore tailings, they will loosen the integration of hydrate products and lower the bulk density. The resulted AAC shows a bulk density of 588­kgm -3 and a compressive strength of 4.20MPa, which is in line with the requirement of A3.5, B06-class AAC products regulated by antoclaved aerated concrete building blocks (GB 11968-2006). The main mineral phases of the products are 0.9nm tobermorite, 1.1nm tobermorite, 1.4nm tobermorite, C-S-H hydration products, ferrotschermakite, anhydrite, calcite, dolomite and residual quartz. The resulted AAC intensity mechanism analysis shows that the strength of the product is obtained by cementing the C-S-H gel, tobermorite and unreacted compositions.

Rotary Microspine Rough Surface Mobility

The Jet Propulsion Laboratory is developing a class of lightweight, highly mobile, crash-proof robots for reconnaissance and security applications. Arrays of independently compliant rotary microspines are used to build wheels that enable the robots to climb stairs, mount curbs, and climb rough vertical walls. This study presents many improvements to the rotary microspine wheels and several new configurations of the robotic platforms, including miniaturized robots weighing less than 10 g. New microspine flexure materials are presented including viscoelastic flexures that dampen the impact of individual hook elements, and mass-manufacturable microspines made using a single cast process over steel wire in place of elastic flexures. Rapid iteration of microspine designs was done using shape deposition manufacturing and a single-wheeled test robot. This process allowed new wheel concepts to go from design to testing in just three days. In addition, new configurations of robots with a powered wheel in the tail have improved reliability and demonstrated new capabilities like climbing heavily painted curbs, climbing stairs with overhanging face angles, and vertical climbing of concrete block buildings as tall as six stories. These results are presented in this paper and in the accompanying video.

Production of price-competitive bricks using a high volume of stone powder sludge waste and blast furnace slag through cementless CaO activation

Stone powder sludge is a waste by-product that is annually produced more than 7.5million tons from the manufacturing process of crushed aggregates in Korea. This study investigated the use of stone powder sludge as a substitute for fine aggregate in brick manufacturing through the CaO activation of the ground-granulated blast-furnace slag (GGBFS) system, which was found to be more suitable than portland cement for the proposed bricks that contained a large quantity of stone powder sludge. This study also discussed the characteristics of leaching, hydration products, and microstructures of hardened samples of proposed mixtures. The trial bricks had high strength, low water absorption, and low material cost. Two of the proposed trial bricks satisfied the requirements of concrete building blocks, ASTM C55, for strength and water absorption at seven days of curing, while the cement brick, with the same quantity of stone powder sludge, failed to fulfill the requirement for water absorption.

Experimental Evaluation of the System-Level Seismic Performance and Robustness of an Asymmetrical Reinforced Concrete Block Building

AbstractIn recent years, research interests in studying the response of different seismic force-resisting systems have been shifting from component-level to system-level studies. Building on the existing knowledge of component-level performance of reinforced masonry shear walls (RMSW), the current study evaluates some similarities and discrepancies between RMSW system-level and component-level responses under seismic loading. The study also focuses on evaluating the system-level seismic robustness of a RMSW building by quantifying key relevant robustness indicators proposed in the literature. To meet the study objectives, an experimental asymmetrical two-story reduced-scale RMSW building was tested to failure under simulated seismic loading. Subsequently, the study first presents a brief summary of the experimental program followed by a discussion of the damage sequence and the load-displacement hysteretic behavior of the RMSW building. In general, the experimental results demonstrated the impact of both ...

Influence of Floor Diaphragm–Wall Coupling on the System-Level Seismic Performance of an Asymmetrical Reinforced Concrete Block Building

Understanding the inelastic seismic response of reinforced masonry shear walls (RMSW) is the first step to develop predictive models of the system-level (i.e., complete building) response under different levels of seismic demand. Such predictive models will not only have to be capable of accurately accounting for the different system-level-specific aspects but will also have to be easy enough to be adopted by design engineers. In this respect, the influence of the floor diaphragms on a building’s seismic response is typically recognized only through the role of the former in distributing the shear forces on the building’s seismic force resisting system (SFRS) as a result of the diaphragms’ in-plane stiffness. Subsequently, the current paper focuses on analyzing experimental data of a series of RMSW tested as individual components and within two asymmetrical building systems. The analyses showed that the out-of-plane stiffness of the floor diaphragms played an important role in flexurally coupling the RMSW aligned along the loading direction with those walls aligned orthogonally. This system-level aspect affected not only the different wall strength and displacement demands but also the failure mechanism sequence and the building’s twist response. For the building system under consideration, the diaphragm-wall coupling resulted in doubling the building’s initial stiffness, and also significantly increasing the building’s strength. The results of the study show that neglecting diaphragm out-of-plane coupling influence on the RMSW at the system-level may result in unconservative designs and possibly undesirable component-level failure modes as a result of violating capacity design principles. To develop an analytical model that can account for the aforementioned influences, simplified load-displacement relationships were developed to predict RMSW component- and system-level responses under lateral seismic loads. In the current study, three approaches were proposed to account for the diaphragm coupling influences on the RMSW response. The developed analytical model presents a useful system-level response prediction tool for displacement- and performance-based seismic design of RMSW buildings.

Waste utilization of building block production

The problem of waste generation in the process of production of lightweight cellular concrete building blocks is investigated. The importance of reduction of the negative impact of waste products on the environment components, as well as search for efficient ways of their beneficial use is stressed. The possibility of usage of production wastes in the form of crushed concrete as adsorbing material for different liquids contaminating the territory is considered. Results of laboratory investigations concerning waste material absorptivity in relation to gasoline, motor oil and shampoo are given. Analysis of research results allowed to reveal the dependencies of waste material absorptivity on the density of the liquids under study. Parameters of absorption effect and the time required to reach adsorption equilibrium were determined. It was demonstrated that usage of production wastes as adsorbent will allow to efficiently neutralize negative impact on the environment in event of incidents involving spill of the liquids contaminating the territory.

Revisiting Attribute-Based Encryption With Verifiable Outsourced Decryption

Attribute-based encryption (ABE) is a promising technique for fine-grained access control of encrypted data in a cloud storage, however, decryption involved in the ABEs is usually too expensive for resource-constrained front-end users, which greatly hinders its practical popularity. In order to reduce the decryption overhead for a user to recover the plaintext, Green et al. suggested to outsource the majority of the decryption work without revealing actually data or private keys. To ensure the third-party service honestly computes the outsourced work, Lai et al. provided a requirement of verifiability to the decryption of ABE, but their scheme doubled the size of the underlying ABE ciphertext and the computation costs. Roughly speaking, their main idea is to use a parallel encryption technique, while one of the encryption components is used for the verification purpose. Hence, the bandwidth and the computation cost are doubled. In this paper, we investigate the same problem. In particular, we propose a more efficient and generic construction of ABE with verifiable outsourced decryption based on an attribute-based key encapsulation mechanism, a symmetric-key encryption scheme and a commitment scheme. Then, we prove the security and the verification soundness of our constructed ABE scheme in the standard model. Finally, we instantiate our scheme with concrete building blocks. Compared with Lai et al. ’s scheme, our scheme reduces the bandwidth and the computation costs almost by half.