Simulated Acid Rain Under The Conditions Of Cement-based Material Properties, Composition, Pore Structure Change Analysis

Acid rain problem is more and more serious, and acid rain corrodes to the cement—base materials also more and more receives attention. The compose, the structure as well as the performance change of cement—base materials bears to acid rain corrosion process is the key in study the cement—base materials destroy, this paper launches the research on this topic. From the research, it is found that: the intensity of test sample first grows than to fall, After the corrosion, the intensity of test sample has not been lower than the initial intensity.Single or double mixed the fly ash, the slag powder have certain improvement function to the cement-based materials bears the acid rain corrossion. after corrosion, the Mortar neutrality depth is small, the superficial color turns yellow,surfacial corrosion serious, The corrosion quayity decide d by the mortar hole structure and the cement-based materials ability bears the acid rain corrosion together.The comparative content of CaO and SO₃ reduced large scale, but of Fe₂O₃, Al₂O₃, SiO₂ massive increased in hydrated cement; ettringite, calcium sulfate and so on matter which have volume expansion have not be found massive productions, but the content of SiO₂ crystalling phase is quit big. After the corrosion, the aluminum hydrated product bythe colloid form, thus has not discovered its characteristic peak.The acid rain attacking process is the hydrated product such as Ca(OH)₂, C-S-H gelatin, hydrated calcium aluminate and hydrated calcium ferrite gelatin unceasing corrosion,and Transform to the silica gel, the aluminum rubber, the hard rubber orthe low calcium silicon ratio hydrated product process.The mortar under spray -illumination circulation corrosion system, internal water -moisture degree between 65% and 95%, simulative acid rain enter into to the test sample difficultly . Along with the corrosion, concrete hole structure more and more compact, concrete internal water -moisture degree more and more high when experiment transform form illumination to spray , acid rain enters the concrete interior to be more and more difficult; The sand and stone exposed causes the active surface in cement base—materials to be more and more small, under above factors together function, acid rain corrode to the cement base—materials only can occur in the surface layer.