Large Volume Of Mineral Admixtures Anti-acid Rain Erosion Research

Air pollution is becoming increasingly serious with the development of industrialization, acid rain is becoming a serious problem in many areas of our country. As a result of acid rain, the bearing capacity of reinforced concrete structure decrease, thereby the structure will exit form its service time prematurely. It will cause the problem getting worse. Therefore, the research of concrete structure which can carry out anti-erosion properties form acid rain is becoming very important.Mineral additions as the sixth component of concrete in application of concrete and concrete structure are getting more and more importance. Adding mineral additions as supplementary cementatious materials can make cost savings and improve the workability of flesh concrete, also they can raise the durability of concrete at a certain extent. In view of this, cement mortar and C25 concrete with a large amount of mineral additions which can carry out anti-erosion performance form acid rain were studied in this paper. the main conclusions of the study are as follows:1,The compressive strength of concrete which were cured under the environment of the standard conservation conditions, the water soaking conditions and the simulated acid rain spray-light and water conditions reduce by their incremental dosage of mineral additions.And the decrement of compressive strength is higher than its anti-folding strength.The cement mortar with single-doped sample of fly ash have the same regularity.2,The compressive strength of cement mortar which were cured under the environment of the standard conservation conditions and the water soaking conditions and cement mortar which was in place of slag by 55% of weight of cement is higher than pure cement mortar specimens. Under the conditions of erosion in a simulated acid rain, cement mortar flexural strength with different content of slag powder is not obvious. But compressive strength rose at first and then decreased by the trend. If the content of slag powder is not more than 55% of weight of cement, the compressive strength of cement mortars which were eroded by simulated acid rain is higher than the pure cement mortars.3,Cement mortars with fly ash and slag in a ratio of 1:4 complex mixed had good compressive strength, even if the complex mixture of 75% content, the intensity and the difference between pure cement mortar is not obvious. 4,Under the conditions of simulated acid rain spray-light and water and the erosion of acid rain is less than the age of 60d,, the single-fly ash cement mortar specimens' acid-rain corrosion values was greater than or close to 1.0; When the age was greater than 60d, acid-rain corrosion coefficient was less than 1.0, and with fly ash increased, the corrosion coefficient was decreasing.5,Under the conditions of simulated acid rain spray-light and water, the rate of decline in the strength of the pure cement mortar samples was higher than cement mortar which mixed with slag.It would maintain the improvement of compressive strength of cement mortar in a appropriate amount of slag powder mixed.6,The addition of mineral admixture can delay the time of corrosion of the concrete surface. From the effect of the delayed deterioration of concrete surface, the fly ash and slag-doped double(FA+SG)≥doped single-slag (SG)≥fly single-doped (FA); With the increase of mineral admixture content, the time of the erosion of the concrete surface deterioration would delay.7,when the amounts of mineral admixture are equal and are eroded by acid rain, the compressive strength of concrete changes in the following order:concrete doubled-doped with fly ash and slag reduces the lest, and then followed by single-doped slag concrete, fly ash alone mixed concrete, the base concrete. In the pre-period of acid rain erosion, the concrete's compressive strength has a growth process. High-strength concrete doubled-doped with fly ash and slag as well as single-doped with slag is stronger than the concrete single-doped with fly ash in anti-acid rain erosion.8,when it is eroded by acid rain, high-strength concrete's compressive strength reduces earlier with the increase of the mineral admixture. But it happens later than the base concrete of 5 to 10 cycles which indicates that the incorporation of mineral admixture delays the time of acid rain eroding the compressive strength of concrete and reduces the degree of deterioration of concrete compressive strength, implying that the incorporation of fly ash and slag improves the concrete's ability of anti-acid ram erosion.9,when it is eroded by acid rain, the quality of concrete reduces in advance with the increase of the mineral admixture. But it reduces earlier than the base concrete; the growth rate of acid rain eroding the quality of concrete in the same period (the quality of growth phase) reduces with the increase of the amount of mineral admixture. In the phase of quality reduction of concrete, the rate of quality reduction of concrete grows with the increase of mineral admixture.10,The carbonation depth of concrete deepened with the increased cycle with the frequency of acid rain. With the mineral admixture in the same volume, the order of the carbonation depth is fly ash and slag concrete double-doped≤single-doped slag concrete≤single-doped fly ash concrete. In other word, the mineral admixture mixed concrete ability of carbonation resistance followed the order:single-doped fly ash concrete≤single-doped slag concrete≤fly ash and slag concrete double-doped concrete. The carbonation depth of acid rain eroded concrete is related to varieties and content of mineral admixture, and fly ash concrete, single-doped reduced the ability of carbonation resistance, and along with increase in fly ash, the ability of carbonation resistance reduced progressively; single doped slag, fly ash and slag double-doped, and the content appropriate to a certain extent, improve the ability of carbonation resistance.