Experimental Study Of Limestone Powder On Properties Of Concrete

Limestone powder concrete as a new type of mineral admixtures, not only low price, convenient processing, low energy consumption, better economic benefit, and can significantly improve the performance of cement base material, has many advantages in technology and economy.This test according to the performance of the related materials,to formulate testing scheme, adopt the method of orthogonal design combined with contrast test of limestone powder content and fineness on the performance of concrete were studied.Orthogonal design of experiment schemes to water-binder ratio(0.30、0.33、0.35), sand ratio(28%, 30%, 32%), lime stone powder content(10%, 10%, 0%), lime stone powder fineness, and study the factors working properties, mechanical properties and shrinkage properties of concrete and natural carbonation resistance ability.Test results show that the sand ratio as the main factors influencing the workability of concrete, the reasonable sand rate was 28%, the dosage of limestone powder on the workability of concrete influence law the same as the sand ratio, the reasonable content of 10%.The influence of limestone powder fineness of concrete is bigger also, the strength of concrete increase with the increase of the limestone powder finenessBased on the results of this test is still in the orthogonal experiment was carried out comparative study, selection of limestone powder of different dosage preparation of concrete, the slump, strength and economy were studied.Test results show that the results show that after adding limestone powder concrete slump, smaller than benchmark group but good adhesiveness and water retention.Concrete compressive strength with the increase of the limestone powder content, showed a trend of decrease after the first increase and limestone powder content was 10%, its various ages(7 d,28 d) the highest compressive strength value, and 28 days strength 59.1 MPa, meet the design strength.This experiment is based on the different fineness(6.9%, 10.5%, 10.5%,6.9%) of limestone powder on cement standard consistency water cave, setting time,strength and concrete, the influence of the degree of strong to do the research.The results show that the grinding thin limestone powder reduces the cement standard consistency water consumption, but little effect, shortened the initial and final setting time of cement.And make the concrete mixture slump increases, increased liquidity and plasticity of mixture;Based on the different age determination of theThrough analyzing the above test results, the best dosage of 10% limestone powder,lime powder fineness was 6.9%.Concrete workability, compressive strength, shrinkage performance meet the needs of ordinary concrete performance accordingly.