Browsing by Author "Bandara, MMHW"

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item: Conference-Full-text
Development of expanded clay as an internally curing concrete aggregate
(Department of Civil Engineering, University of Moratuwa, 2016-12) Bandara, MMHW; Mampearachchi, WK; Hettiarachchi, MTP
Internal curing is an emerging technology in cement concrete industry to replace the conventional curing process by supplying excess water throughout the concrete mixture. Internally curing will outperform in road construction industry than conventional curing methods due to its convenience of use in harsh environmental conditions. The research mainly focuses on finding a suitable internal curing concrete aggregate (ICCA) in Sri Lanka to use in cement concrete applications. The study presents a summary of internally curing concrete aggregate types available globally. Expansive clay available in the selected locations were able to process and develop as internal curing aggregates.
item: Conference-Abstract
Development of expanded clay as internally curing concrete aggregate
(Department of Civil Engineering, University of Moratuwa., 2016-08) Bandara, MMHW; Mampearachchi, WK; Pasindu, HR
The increase of highway and other related structures development of any country due to economic boom may lead to introduce fast and sustainable construction techniques and materials. Internal curing is a revolutionary curing process which has lot of advantages more than the conventional curing process. Internal Curing is a practical and applicable method that can supply extra water throughout the concrete mixture in order to complete the cement hydration process. This can be done by using lightweight aggregate which replaces some of normal and conventional aggregate in the concrete mixture. Water that absorbed inside expanded lightweight aggregate can provide ad-additional water throughout the concrete mixture for curing process. According to the international context, lot of international researches on performance evaluation of internally cured concrete has been conducting. And also this method is used internationally for various concrete applications. Internal curing process is widely used for concrete road construction because of its advantages. As a one of rapid developing country, in Sri Lanka yet there is no better technical knowledge and materials to implement this method for road construction process. And also There is no good research in order to find locally available materials and to evaluate performance of internally cured concrete for Sri Lankan road construction according to the Sri Lankan climate and readily available local resources. This research focused on the method of selecting suitable locally available resources in any country as internally curing concrete aggregate and to evaluate internally cured concrete relevant to the local context of that country. As well the main objective of this research is to select or produce a suitable internally curing concrete aggregate using readily available local resources in Sri Lanka and to find a suitable method to develop the marginally suitable aggregates. That includes the characterization of locally available lightweight aggregates to evaluate the performance of internally curing concrete.
item: Article-Full-text
Enhance the properties of concrete using pre-developed burnt clay chips as internally curing concrete aggregate
(Elsevier, 2019) Bandara, MMHW; Mampearachchi, WK; Anojan, T
Materials of internal curing concrete have been developed in many countries. Some of those materials are superabsorbent polymers, light weight aggregate (LWA), normal weight aggregate, recycled aggregate, bentonite clay, furnace slag and bottom ash. The most popular internal curing material is LWA. LWA are not available in most countries. Thus, the production of internal curing concrete (ICC) was limited for few countries. Consequently, this research was focused on the utilization of burnt clay chips as a new material to enhance the properties of ICC. Furthermore, water–cement (w/c) ratio and workability of ICC were investigated to develop high strength internal curing concrete (SICC). The water absorption and desorption capacity of porous aggregates are basically depends on the capillary interaction between water and the pore structure. Thus, formation of an effective pore structure within the burnt clay chips becomes the most important thing. Thus, Red clay was selected and different pore structures were developed within the clay mass by heating trough furnace. The heating temperature ranged from 800 to 1300 °C. The burnt clay chips produced at 900 °C was identified as an effective ICC aggregate. Afterwards, the pre-developed burnt clay chips (DBCC) were produced in larger scale. During the production of burnt clay chips, clay blocks (150 × 250 × 14 mm) were produced and heated at 900 °C using industrial furnace. Subsequently, heated clay blocks were crushed and sifted through 4.75 mm sieve to obtain fine clay chips. The water absorption capacity and the dry apparent density of DBCC was recorded as 15.5% and 1.8 g/cm3 respectively. Finally, grade 25, 30 and 35 concretes were prepared to study the effect of workability and w/c ratio. Moreover, three different concrete samples were prepared from each concrete grade; external curing concrete (ECC), ICC and SICC. ICC samples increased the slump value in 12%. Furthermore, the compressive strength of ICC and ECC were almost same for all three concrete grades. SICC sample increased the compressive strength in 9% while maintaining the required workability and same cement content of ECC sample. Thus, it is concluded that, DBCC can be used as an effective internal curing agent to increase the compressive strength and workability of ICC.
item: Conference-Abstract
Evaluation of water absorption characteristics of internal curing concrete aggregate with respect to the processing temperature of expanded clay types
(Department of Civil Engineering, 2017-07) Bandara, MMHW; Mampearachchi, WK; Pasindu, HR
The increase of the new technological development of any country may lead to introduce fast and sustainable construction techniques and materials. Internal curing is one of a revolutionary curing process which has more advantages than the conventional curing process. Internal Curing can supply extra water throughout the concrete mixture in order to complete the cement hydration process. This can be done by using lightweight aggregate which replaces some of the normal and conventional aggregate in the concrete mixture. Water that absorbed inside expanded lightweight aggregate can provide additional water throughout the concrete mixture for curing process. This method can be effectively used for concrete road and related infrastructure construction since the traditional curing methods have some inherent limitations in using road infrastructure construction. Expanded clays can be used to produce suitable aggregates for internal curing. So, heating temperature is a critical parameter in the production of suitable ICC aggregate using expanded clay. Water absorption and desorption are the main requirements of internal curing. This research is mainly focused on selecting suitable heating temperature which gives and optimum water absorption. It includes the selection of suitable expanded clay type to produce ICA. Different clay samples were studied to build a relationship between heating temperature and water absorption. Clay samples were prepared using a mold and that clay samples were heated at various temperatures (in the range of 800 °C to 1300 °C). Heated clay samples were analyzed through the laboratory tests. The bloating coefficient of the clay samples were varied from 1.0 to 2.2. Higher temperature has the higher bloating coefficient but at 1300oC the clay samples were begun to melt due to the phase change of the structure of clay molecules. Higher water absorption values are experienced before the phase change of the clay molecules.
item: Article-Full-text
Mitigate the curing problems of concrete pavements by using heated non-expansive clay particles as internal curing agent
(Taylor & Francis, 2021) Bandara, MMHW; Mampearachchi, WK
Internal curing concrete can be used in the production of concrete road pavements, bases, etc. It reduces the formation of drying shrinkage cracks and saves lots of money and time that spend on ineffective external curing processes. Unfortunately, internal curing aggregates (ICAs) are not available in most countries. Thus the production of internal curing concrete (ICC) is limited to a few countries. This research focuses on developing an effective ICA using non-expansive clay type. Consequently, a non-expansive clay type was selected and heated at various temperatures ranging from 800◦C to 1300◦C at intervals of 100◦C. Afterwards, heated clay samples were crushed into fine aggregates. The optimum heating temperature which gives the required properties as ICA was identified as 900◦C through an extensive analysis followed by pore structure of heated clay aggregates. The produced aggregate achieved 1.8 g/cm3 density value, 15.5% of water absorption. Subsequently, ICC achieved higher compressive strength and workability more than the conventional concrete without any external curing process. Moreover, the aggregate reduced the drying shrinkage of concrete.