{"title":"Estimation Model for Concrete Slump Recovery by Using Superplasticizer","authors":"Chaiyakrit Raoupatham, Ram Hari Dhakal, Chalermchai Wanichlamlert","country":null,"institution":"","volume":108,"journal":"International Journal of Civil and Environmental Engineering","pagesStart":1588,"pagesEnd":1594,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/10003133","abstract":"This paper aimed to introduce the solution of concrete\r\nslump recovery using chemical admixture type-F (superplasticizer,\r\nnaphthalene base) to the practice in order to solve unusable concrete\r\nproblem due to concrete loss its slump, especially for those tropical\r\ncountries that have faster slump loss rate. In the other hand, randomly\r\nadding superplasticizer into concrete can cause concrete to segregate.\r\nTherefore, this paper also develops the estimation model used to\r\ncalculate amount of second dose of superplasticizer need for concrete\r\nslump recovery. Fresh properties of ordinary Portland cement\r\nconcrete with volumetric ratio of paste to void between aggregate\r\n(paste content) of 1.1-1.3 with water-cement ratio zone of 0.30 to\r\n0.67 and initial superplasticizer (naphthalene base) of 0.25%-1.6%\r\nwere tested for initial slump and slump loss for every 30 minutes for\r\none and half hour by slump cone test. Those concretes with slump\r\nloss range from 10% to 90% were re-dosed and successfully\r\nrecovered back to its initial slump. Slump after re-dosed was tested\r\nby slump cone test. From the result, it has been concluded that, slump\r\nloss was slower for those mix with high initial dose of\r\nsuperplasticizer due to addition of superplasticizer will disturb\r\ncement hydration. The required second dose of superplasticizer was\r\naffected by two major parameters, which were water-cement ratio\r\nand paste content, where lower water-cement ratio and paste content\r\ncause an increase in require second dose of superplasticizer. The\r\namount of second dose of superplasticizer is higher as the solid\r\ncontent within the system is increase, solid can be either from cement\r\nparticles or aggregate. The data was analyzed to form an equation use\r\nto estimate the amount of second dosage requirement of\r\nsuperplasticizer to recovery slump to its original.","references":null,"publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 108, 2015"}