Comparison between CLC mix designs and mortar compositions towards drying shrinkage cracks | |
| Author | Dabarera, Gangodawilage Patrick Arosha |
| Call Number | AIT Caps. Proj. no.CIE-14-28 |
| Subject(s) | Concrete--Shrinkage Lightweight concrete |
| Note | A capstone project report submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Engineering in Civil and Infrastructure Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Caps. Proj. ; no. CIE-14-28 |
| Abstract | This study investigates the relationships and comparisons between Cellular Lightweight Concrete (CLC) mix designs and mortar compositions in order to minimize drying shrinkage cracks. CLC is primarily a substitution of coarse aggregate in concrete by air or gas in the form of voids which are entrapped by appropriate foaming agent. Due to vast amount of benefits of this type of concrete, the technology was adopted to cast concrete blocks in many countries. However, drawback to this technology has occurred due to shrinkage cracking of the constructed walls with CLC blocks. This drawback provided the motivation to investigate drying shrinkage behavior of CLC blocks and mortar compositions by varying parameters of the mixes. Six CLC mix designs were casted including existing one by varying fly ash amounts and water contents. Three mortar compositions were casted by varying cement to sand ratios. All the experiments were conducted according to ASTM standards. Drying shrinkage measurements were obtained until 60 days after casting CLC specimens. Apart from drying shrinkage, compressive strength and dry density measurements were obtained for all CLC mix designs. Mortar specimen measurements were obtained until 28 days after casting due to time restrictions. It was proven that first two weeks is vital towards generation of cracks due to shrinkage characteristic. In the mix designs with constant water to cement ratio, higher the fly ash incorporated in CLC, lower the shrinkage occurred. The results indicated that FA30/WC0.375 was the CLC mix design with highest suitability among all the others in terms of drying shrinkage, compressive strength and dry density. From the comparison of CLC and mortar it was concluded that the high difference between drying shrinkage rates of mortar and CLC mix designs have a possible significant impact towards cracking of CLC block walls. The above stated difference could be minimized if use FA30/WC0.375 CLC mix design and a mortar containing 1:3.5 of cement to sand ratio. |
| Year | 2014 |
| Corresponding Series Added Entry | Asian Institute of Technology. Caps. Proj. ; no. CIE-14-28 |
| Type | Capstone Project |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Civil and Infrastructure Engineering (CIE) |
| Chairperson(s) | Teraphan Ornthammarath; |
| Examination Committee(s) | Punchet Thammarak ;Kawin Worakanchana; |
| Degree | Capstone Project (B.Sc.)-Asian Institute of Technology, 2014 |