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Design in unreinforced masonry to EN 1996
Published in Chanakya Arya, Design of Structural Elements, 2022
Concrete blocks are manufactured in three basic forms: Solid, cellular and hollow (Figure 5.7). Solid blocks have no formed holes or cavities other than those inherent in the material. Cellular blocks have one or more formed voids or cavities which do not pass through the block. Hollow blocks are similar to cellular blocks except that the voids or cavities pass through the block. The solid material between holes and the face of the unit is referred to as the shell whereas the solid material between voids is referred to as the web. Product characteristics such as the percentage of voids and the thickness of webs and shells are used to assign blocks to one of four groups, which is necessary in order to evaluate the characteristic compressive strength of masonry as discussed in Section 5.6.2.
Internal partitions and walls
Published in Derek Worthing, Nigel Dann, Roger Heath, of Houses, 2021
Derek Worthing, Nigel Dann, Roger Heath
Concrete blocks are laid in a cement/sand mortar (often with a plasticiser added to aid curing) or cement/sand/lime mortar. A strong mortar, i.e. one with a high proportion of cement, should be avoided as it limits the ability of the partition to accommodate thermal and moisture movement, which may result in cracking. In addition, the concrete blockwork should be allowed to dry thoroughly before dry-lining or plastering takes place, as water absorbed by the blocks (from standing in the rain) causes slight expansion and plaster applied before the blocks have dried out will crack as the blocks slowly shrink. Where the partitions return at right angles, cut blocks are used to maintain the bond, and where doors are to be incorporated, steel or concrete lintels are built in over the opening.
Statistical analysis of corrosion-induced area loss of steel bar in concrete
Published in Hiroshi Yokota, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations, 2021
F. Tang, L. Zhao, H. Cui, H.N. Li, H. Wang, X. Wang, Z. Lin, H. Pan
Concrete block specimens containing 8 pieces of steel bar was prepared and tested as shown in Figure 2. The concrete block has a dimension of 127×229×508 mm. To limit the middle portion of 51 mm to be exposed to the corrosive environment, the two ends of each steel bar were embedded in a PVC pipe with a length of 152 mm.
Study on coconut shell concrete hollow blocks and the shrinkage, durability and bond properties of mixes used
Published in European Journal of Environmental and Civil Engineering, 2021
K. Gunasekaran, G. Pennarasi, V. Deeptha Thattai, T. N. Brinda
In the construction industry, traditional building materials like cement, bricks, stones and steel are replaced with new materials having equivalent or relatively equivalent properties. Hollow concrete blocks are becoming more popular as they are extremely versatile and durable (Gao, Roux, Teodosiu, & Zhao, 2004). Also, better-quality construction activities, dearth of conventional building materials and copiously available wastes have promoted the development of new building materials (Sunil Kumar, 2002). Efforts are being made to recycle different wastes and use them in different applications to save the environment. Sugarcane bagasse, paddy and wheat straw and husk, vegetable wastes, oil, jute fibre, groundnut shell, wooden mill waste, cotton stalk, CS and husk are some of the sources from agricultural sector (Gupta, 2000; Maudgal, 1995; Pappu, Saxena, & Shyam, 2007; Sengupta, 2002). This study used CS as aggregate in the production of hollow blocks, so that a viable route can be formed to manage the CS waste and also to find an alternate aggregate in the production of hollow blocks.
Advances in state-of-art valorization technologies for captured CO2 toward sustainable carbon cycle
Published in Critical Reviews in Environmental Science and Technology, 2018
Shu-Yuan Pan, Pen-Chi Chiang, Weibin Pan, Hyunook Kim
A concrete block comprises of water, cement, coarse and fine aggregates, chemical admixture, and SCM. Studies have been carried out to evaluate the utilization performance of carbonated solid wastes as SCMs in blended cement (Pan et al., 2015d) and a fine aggregate in concrete (Monkman et al., 2009). Normally, the use of SCMs in blended cement may reduce the early-age strength and increase the later-age strength of the concrete, as compared with the use of pure OPC (Caldarone et al., 2005). However, a carbonation product such as CaCO3 is superior to the original CaO or Ca(OH)2 in alkaline solid wastes, in terms of physical properties. Since the CaCO3 is a highly elasticity-resistant material, it can improve early strength of cement mortar. CaCO3 also could create vacuum within the cement matrix; therefore, liquid cannot easily intrude into the structure to induce corrosion or damage (Chi et al., 2002). Aside from the physical enhancement, the CaCO3 product may induce the chemical enhancement effect which might be attributed to the hydration of C3A phase to form stable calcium carboaluminate (C3A·CaCO3·11H), as shown in Eq. (5). This reaction could develop a higher mechanical strength in the early stage (Hawkins et al., 2003). In the meantime, the formed by-product (C3A·0.5CaCO3·0.5Ca(OH)2·11.5H) is relatively unstable and will be continuously converted to calcium carboaluminate after 1 day, as described in Eq. (6).
Analysis of heat transfer through a high strength concrete with circular pipe in a safety vessel of reactor vault
Published in International Journal of Ambient Energy, 2018
M. Anish, B. Kanimozhi, S. Ramachandran, J. Jayaprabakar, N. Beemkumar
The RV model is a scaled prototype of actual RV in a nuclear reactor, as shown in Figure 1. It consists of a cylindrical block made of high strength concrete with a CS pipe passing through its centre. Concrete block is of 10′′ in diameter and 12′′ in length (Kharita et al. 2008). The CS pipe is of 1′′ in diameter and 18′′ in length. Both the ends of CS pipe are attached to flange through which it is connected to the external set-up. The RV model is then assembled to the external set-up through which the heat transfer fluid (water) at a higher temperature is circulated. The heat from the water is absorbed by the tubes and transmitted through the concrete material.