Portland Pozzolana Cement (PPC)
The Portland Pozzolana Cement (PPC) is a kind of Blended Cement which is made by either intergrinding of OPC clinker close by gypsum and pozzolanic materials in explicit degrees or squashing the OPC clinker, gypsum and Pozzolanic materials independently and completely mixing them in specific extents.
Pozzolana is a characteristic or fake material containing silica in a responsive structure. It might be additionally examined as siliceous or siliceous and aluminous material which in itself has pretty much nothing, or no cementitious properties yet will in finely isolated structure and within the sight of dampness, synthetically respond with calcium hydroxide at conventional temperature to shape mixes having cementitious properties. It is fundamental that pozzolana be in a finely separated state as it is at exactly that point that silica can join with calcium hydroxide (freed by the hydrating Portland concrete) within the sight of water to frame stable calcium silicates which have cementitious properties. The pozzolanic materials normally utilized are:
- Volcanic Cinder
- Calcined Earth
- Fly Cinder
- Silica Exhaust
The Indian principles for Portland Pozzolana Cement (PPC); have been issued in two sections dependent on the sort of pozzolanic materials to be utilized in assembling of Portland Pozzolana Cement as given underneath:
IS 1489 (Part 1) 1991, Portland Pozzolana Cement – particular (fly fiery remains based)
IS 1489 (Part 2) 1991, Portland Pozzolana Cement (PPC) – particular (Calcined dirt based) the nature of flyash or calcined earth to be utilized in assembling of PPC is additionally indicated by BIS in the accompanying principles:
IS 3812 1981 – detail for flyash as pozzolana and admixture IS 1344 1981 – determination for calcined mud pozzolana In perspective on the accessibility of good quality fly fiery remains in plenteous amount, the utilization of calcined mud based pozzolana bond is logically diminishing. The flyash is a waste result of Thermal power Plant which makes transfer issues at Thermal power plant site. The yearly creation of flyash in India is around 70 million tons for each annum. This would increment in future relying on the new coal based warm power plants to be introduced in the nation. The present usage of fly fiery remains underway of mixed concrete in India is small.
Fly slag is the fiery debris accelerated electrostatically from the fumes vapor of coal terminated power station. The fly fiery remains particles are circular and are by and large of higher fineness than concrete with the goal that the silica is promptly accessible for response. According to IS 3812: 1981 the level of silica and alumina ought to be least 70% and greatest misfortune on start 12%. Much prevalent quality fly fiery debris is accessible from Indian warm power plants than determined in IS code.
The Portland Pozzolana Cement makes solid progressively impermeable and denser when contrasted with Ordinary Portland Cement. The long haul quality (90 days or more) of Pozzolana bond is better contrasted with OPC. The pozzolanic material responds with calcium hydroxide freed by the hydrating Portland Cement and structures cementitious mixes commonly known as C-S-H gel. The response can be given as under:
C3S + 6H – > C3S2H3 + 3 Ca(OH)2
2C2S + 4 H – > C3S2H3 + Ca (OH)2
Ca(OH)2 + (SiO2 + Al2O3) – > C3S2H3 + Other parts
The flyash changes over Ca(OH)2 in to helpful cementitious compound (C3S2H3) along these lines expanding the properties of solidified cement.
The Portland Pozzolana Cement creates less warmth of hydration and offers more prominent protection from the assault of forceful waters than typical Portland Cement. Besides it lessens the draining of calcium hydroxide freed amid the setting and hydration of concrete.