Strength development of pozzolana-cement mortars subjected to accelerated curing | |
| Author | Wutthipong Moungnoi |
| Call Number | AIT Thesis no.ST-94-34 |
| Subject(s) | Pozzuolanas Mortar--Testing |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The purpose of this study is to investigate experimentally the strength development of mortars containing different types of pozzolana subjected to an accelerated curing condition. The accelerated curing adopted in this experiment involves the immersion of mortar specimen in 70°C hot water for a duration of 12, 24, 36,48 and 60 hours. The main parameter are the types of pozzolana and their percentage replacements. Four types of pozzolana are investigated namely rice straw ash (RSA), peanut shell ash (PSA), rice husk ash (RHA) and Mae-Moh fly ash obtained from two different sources. The percentage replacements of pozzolana are 0%, 20%, 35% and 50% by weight of cement. Ordinary Portland cement (OPC) Type I is used throughout this experiment. The mortar specimens cured under normal and accelerated curing are tested for their compressive strengths at different ages and the results are compared. Test results revealed that the water-cementitious material ratios of the agricultural ash increase with increasing percentage replacement for mortars having a constant flow value. This is contrary to the water-cementitious ratios of the fly ash mortars which decrease with increasing percentage replacement of ash. The strength developments of Mae-Moh fly ash mortar and OPC mortar were more or less the same for 20% and 35% replacement. The early strength of 50% by weight of cement indicated that too high percentage replacement of all types of pozzolana resulted in very low.strength. These may due to the fact that for 50% replacement the cement content in the mix was rather low and the chemical reaction between the :;ilica in pozzolana and the liberated calcium hydroxide was slow. The 60 - hour strength of all types of mortars were only slightly higher than the 24 - hours strength. The poor strength development of both agricultural ash and fly ash mortars at 60 hours can be explained by the fact that heating the mortar too rapidly or at high temperatures when the mortar was still fresh reduces its long-term strength. |
| Year | 1994 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul |
| Examination Committee(s) | Karasudhi, Pisidhi ;Aoyagi, Yukio ;Nuttawuth Udayasen |
| Scholarship Donor(s) | The Royal Thai Government |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |