【摘要】：隨著建筑業(yè)的高速發(fā)展，混凝土用量越來越大，天然砂資源也將越來越緊張，許多地方因亂采、亂挖已造成嚴重的環(huán)境污染問題，應用機制砂部分或者全部替代天然砂作為混凝土細集料的趨勢明顯。但是，生產工藝對機制砂特性產生重要的影響，機制砂特性與機制砂混凝土性能密切相關，通過測試混凝土性能來揭示機制砂特性對混凝土的影響規(guī)律。研究了機制砂中石粉含量、MB值對混凝土的工作性、力學性、早期抗裂、干燥收縮、抗氯離子滲透性能、抗硫酸鹽侵蝕性能的影響規(guī)律；利用數(shù)字圖像處理技術研究了機制表面粒形的評價方法以及其對混凝土性能的影響規(guī)律；結合機制砂特性，利用軟件優(yōu)化機制砂混凝土配合比，為推廣機制砂在混凝土中的應用提供理論基礎和參考價值。揭示的主要影響規(guī)律和研究結果如下： 1)研究了機制砂中石粉含量對混凝土性能的影響,結果顯示，適量的石粉能夠提高混凝土的工作性能和抗壓強度，在本試驗條件下，當石粉含量在3%~20%時，對于C30、C40和C60混凝土，當石粉含量在15%、10%和5%時拌合物具有最好的工作性；當石粉含量在20%、10%和8%時機制砂混凝土28天抗壓強度達到最大值。 2)機制砂中適量的石粉能夠機制砂的混凝土的抗硫酸鹽侵蝕性能，對抗氯離子滲透性能不利，當機制砂中石粉含量在8%~10%范圍內時，混凝土的干縮增長最快。 3)研究了機制砂MB值的影響因素，泥粉含量、種類以及細度對機制砂MB影響較大，相比較于巖土，黏土類的泥粉對MB值的影響更大。泥粉含量和MB值的相關系數(shù)R2=0.991；在等含量的條件下，機制砂MB值都是隨著泥粉或者石粉的細度增加而增加。 4)機制砂混凝土的工作性能隨MB值的增加而減小，抗壓強度都是隨著機制砂MB增大呈先增大后減小的趨勢，當泥粉含量從0%增加到5%時，MB值從0.3增加到4.65；混凝土塑性開裂隨著MB值的增大而增大，抗氯離子滲透性能隨著MB值的增大而降低，在本試驗條件下，MB值從0.3增加到4.65時，C60混凝土抗氯離子滲透等級從Q-Ⅳ下降到Q-Ⅲ。 5)利用MATLAB和IPP軟件的數(shù)字圖像處理技術可對機制砂表面粒形進行評價，，并以二維圓度和三維球度作為評價指標，圓度和球度與水泥膠砂流動度的相關系數(shù)分別為R2=0.717和R2=0.689，球度和間隙率的相關性R2=0.908；圓度和流動時間的相關性R2=0.71。機制砂表面粒形對混凝土的工作性能影響較大，對混凝土力學性能影響較小。 6)結合機制砂石粉含量、MB值，利用MATLAB軟件優(yōu)化函數(shù)，編制優(yōu)化程序優(yōu)化C30機制砂混凝土配合比，優(yōu)化前后的C30混凝土基本工作性和力學性能相當，在保證混凝土的基本工作性能和力學性能條件下，提高經濟效應。
[Abstract]:With the rapid development of the construction industry, the quantity of concrete is increasing, and the natural sand resources will be more and more tight. Because of random mining and digging in many places, serious environmental pollution problems have been caused. The tendency of using machine-made sand to replace natural sand as concrete fine aggregate is obvious. However, the production process has an important effect on the characteristics of the machine-made sand, and the characteristics of the machine-made sand are closely related to the properties of the machine-made sand concrete. The effects of the characteristics of the machine-made sand on the concrete are revealed by testing the properties of the concrete. The effects of rock powder content MB value on the workability, mechanical properties, early crack resistance, drying shrinkage, chloride ion penetration resistance and sulfate erosion resistance of concrete were studied. The evaluation method of mechanism surface grain shape and its influence on concrete performance are studied by using digital image processing technology, and the software is used to optimize the mix ratio of mechanism sand concrete, combining with the characteristics of mechanism sand. It provides theoretical basis and reference value for popularizing the application of machine-made sand in concrete. The main results are as follows: 1) the effect of stone powder content in machine-made sand on concrete performance is studied. The results show that proper amount of stone powder can improve the working performance and compressive strength of concrete. Under this condition, when the content of stone powder is 3 ~ 20, the mixture has the best workability for C30% C40 and C60 concrete, and when the content of stone powder is 15% or 10% and 5%, the mixture has the best workability. When the content of stone powder is 20% and 8%, the compressive strength of concrete made of machine-made sand reaches the maximum value in 28 days. 2) the concrete with proper amount of stone powder in machine-made sand can resist sulfate erosion, which is unfavorable to the permeability of chloride ion. When the content of stone powder in machined sand is in the range of 8% or 10%, the dry shrinkage of concrete increases fastest. 3) the influencing factors of MB value of machined sand are studied. The content, type and fineness of clay have great influence on MB of machined sand, compared with rock and soil. Clay silt has a greater effect on MB value. Under the condition of equal content, the MB value of machined sand increases with the increase of fineness of mud or stone powder. 4) the working performance of machine-made sand concrete decreases with the increase of MB value. The compressive strength increased first and then decreased with the increase of the MB of machine-made sand. When the content of mud powder increased from 0% to 5%, the compressive strength increased from 0.3 to 4.65, and the plastic cracking of concrete increased with the increase of MB value. The resistance to chloride ion penetration decreased with the increase of MB value. Under this test condition, when the value of MB is increased from 0.3 to 4.65, the resistance to chloride ion permeation of concrete can be reduced from Q- 鈪

本文編號：2133889