| Abstract [eng] |
My research plot is a white topping mix investigation utilizing crumb rubber (CR) as a fine aggregate, waste glass powder (GP) and fly ash as a cementitious material. White topping is one of the laying technique for the damaged asphalt layers. The damaged asphalt layer will mill off up to destructed depth, and concrete mix will be laid above the milled asphalt layer is called white topping. A standard white topping mix will contain powerful superplasticizers, admixtures, and fibers. In this research, I am planning to prepare three sets of mixes. The control mix was prepared using water-reducing admixture, shrinkage reducing admixture, prefabricated air bubbles, and macro synthetic polypropylene fibers. These materials were selected according to white topping industry's recommendation In the First Set, crumb rubber is substituted as a fine aggregate by the proportion of 5 kg/m3, 10 kg/m3, 20 kg/m3. Aim of adding crumb rubber in concrete to get an excellent freezing-thawing effect compared to a special air-entraining agent. Naturally, rubber will dispense good toughness and excellent energy absorption. In the Second Set, crumb rubber was treated with carboxylate styrene-butadiene latex (SBR) to change rubber hydrophobic nature to hydrophilic. After treatment, rubber surface will attain a hydrophilic nature; a hydrophilic nature will create a proper bond with hydrated cement paste and avoid agglomeration (due to low-density crumb rubber). Same amount 5 kg/m3, 10 kg/m3, 20 kg/m3 of treated crumb rubber substituted as a fine aggregate. Generally, concrete strength is getting reduced by adding crumb rubber. So, I decided to add waste glass powder and fly ash as a part of Portland cement to make an extra pozzolanic reaction for concrete strength. There are three batches in the third set; the first two batches consist of waste glass powder and treated crumb rubber (TCR). In the third batch, 10%(weight of cement) of fly ash added along with waste glass powder as an additive in rubber concrete. We prepared three batches in each set to investigate concretes' workability, durability, and mechanical properties. At the end of research, we prepared two batches with new rubber material (fibrous crumb rubber); it is finer than normal crumb rubber and contains more microfibers. The following tests: slump test, fresh concrete density, fresh concrete air content, compressive strength, pozzolanic strength activity index, dry density, flexural strength, fracture energy, freezing-thawing, porosity parameter, and scanning electron microscope are conducted for untreated rubber, treated rubber, and treated rubber glass powder concretes. For fibrous crumb rubber concretes, conducted fresh concrete tests and freezing-thawing investigation. After all samples investigation, ultra-thin white topping design procedure was described according to New Jersey state and finally discussing white topping laying procedure. |
