Research Of The Corrosion Inhibitor For Concrete Based On Seawater And Sea Sands

In recent years, the current of seawater and sea sand be used as building materials is obvious, but chloride and sulphate included in them will accelerate corrosion rate of rebar in concrete, they have an adverse effect on durability of concrete, so, the application of seawater and sea sand in concrete be restricted.For prolonging the useful life for structure of concrete based on seawater and sea sands, reducing corrosion rate of rebar in concrete based on seawater and sea sands by using highly active corrosion inhibitor and synergistic reaction of different technical measures is one of important ways. At present, composite corrosion inhibitor has become a hot in field of corrosion inhibitor overseas, it has many advantages,such as highly active,reliable,environmental protection and so on, whereas, domestic scholar research on test analysis of corrosion inhibitor's performance mainly, seldom study about compositional formulation and action mechanism of corrosion inhibitor, so, strengthening research about compositional formulation and mechanism of corrosion inhibitor have significance for prolonging the useful life for structure of concrete based on seawater and sea sands.The effects of corrosion inhibitors (Composite corrosion inhibitor A1,A2,A3and Mucis ad 19L/D),curing conditions,mineral admixture,moulding process on rebar corrosion in mortar and/or concrete based on seawater and sea sands were studied in this paper. Phase composition of cement hydratation product,microstructure and composition of the interface between rebar and concrete,polar molecule adsorbed in rebar surface were analyzed by way of X-ray diffraction(XRD),Transmission scanning electron microscopy (TSEM),X-ray energy dispersive spectroscopy (XEDS),Fourier transform Raman spectrum(FT-Raman), discussed action mechanism of corrosion inhibitor. Research shows:①Acceding single composition corrosion inhibitor to mortar based on seawater and sea sands can delay the damaging effects of Cl- on rebar, and improve the stability of rebar passive film, rusty accumulation rate and weight loss of rebar for samples soaked in seawater decreased obviously after 30 times soak-warm circulation, according to slope shifted to negative direction of polarization potential of rebar and corrosion rate of rebar, estimating several trial single composition corrosion inhibitors'corrosion inhibition ranked from strong to weak for TEA≈AMP>MFP>LiNO3≈LiOH>DMEA>TES. ②Acceding composite corrosion inhibitor to mortar and/or concrete based on seawater and sea sands can observably reduce rusty accumulation rate and weight loss of rebar, improve ability to resist chloride ion penetration of mortar and/or concrete, corrosion rate of rebar for samples soaked in seawater,3.5%NaCl solution,6.0%NaCl solution respectively increased weakly after 100 times soak-warm circulation, and remain stable corrosion inhibition over an extended period. Corrosion inhibition is best when acceding 1.4%～1.7% A3 corrosion inhibitor to mortar and/or concrete, A1 and Mucis ad 19L/D'corrosion inhibition is nearly.③With regard to concrete based on seawater and sea sands, samples soaked in seawater lead rusty accumulation rate and weight loss of rebar increased dramatically, comparing with samples soaked in NaCl solution; Synergistic effect can be produced when acceding metakaolin and composite corrosion inhibitor at the same time, and corrosion inhibition enhanced obviously, corrosion inhibition was enhanced with the increase content when metakaolin content is less than 20%; Corrosion inhibition was enhanced when rebar being wrapped cement paste, and acceding A3 into cement paste, corrosion inhibition was enhanced with the increase thickness when cement paste thickness is less than 7.5mm.④Acceding corrosion inhibitor A2 to mortar based on seawater and sea sands reduced mobility and intensity of mortar, corrosion inhibitor A1 and A3 increased mobility, without negative influence on strength of mortar; Corrosion inhibitor A3 delayed hydration of cement, mainly restrained forming and developing of C-S-H gel early, but enhanced compactibility of concrete structure later period; Corrosion inhibitor A3 can adsorb on interface between rebar and concrete by function of adsorption,airproofed,decentralization,chemical reaction deposition of inorganic salt and so on, thus it also improved stability of rebar passive film.⑤It can produce good cooperativity corrosion inhibition when corrosion inhibitor being made up of alcohol amine compound,surfactant,phosphate,nitrate based on different mechanism of corrosion inhibition, further more, it have a better corrosion inhibition than Mucis ad 19L/D, the proper poraver of it is 1.4~1.7wt.% for cementing material.