铁尾矿机制砂中硫含量对C30混凝土性能的影响  

Effect of Sulfur Content on Properties of C30 Iron Tailings Mechanism Sand Concrete

作　　者：王林 潘月凡 郭宏[2] 贺鑫鑫 杜艮坤 

机构地区：[1]北京建筑大学土木与交通工程学院,北京100044 [2]中铁十七局集团有限公司,山西太原030006

出　　处：《混凝土世界》2024年第8期21-26,共6页China Concrete

基　　金：中铁上海工程局集团2022年科研计划“铁尾矿混凝土的研制与工程应用”(H22148)。

摘　　要：铁尾矿机制砂被广泛应用于混凝土中,然而部分铁尾矿机制砂中硫含量过高,可能会造成混凝土膨胀开裂。本文配制了不同硫含量的铁尾矿机制砂混凝土,研究硫含量对混凝土工作性能、力学性能和耐久性能的影响规律,并采用X R D、压汞、SEM等微观测试分析了铁尾矿机制砂中硫含量对混凝土性能的影响机理。结果表明:铁尾矿机制砂中硫含量的增加显著影响混凝土的工作性能;硫含量为2%的C30铁尾矿机制砂混凝土早期强度最高,养护龄期在3 d和7 d时,混凝土抗压强度比空白组分别提升了14.4%、11.7%,其抗碳化性能和抗氯离子扩散能力均优于其他硫含量的混凝土。少量的硫化物可以提供充足的SO42-,激发水泥混合材水化反应的进行;含硫量过高则会导致混凝土中的A Ft和石膏等膨胀性晶体增加,混凝土内部产生较大应力,造成混凝土开裂,对后期强度发展不利,对于铁尾矿机制砂混凝土,硫含量不宜超过4%。Iron tailings mechanism sand is widely used in concrete,however,the sulfur content of some iron tailings mechanism sand is too high,which may cause concrete expansion and cracking.In this paper,we formulated concrete with different sulfur content of iron tailing mechanism sand,studied the inf luence of sulfur content on the working performance,mechanical properties and durability of concrete,and analyzed the inf luence mechanism of sulfur content in iron tailing mechanism sand on concrete by using microscopic tests,such as XRD,mercury compression,SEM,and so on.The test results show that the increase of sulfur content in iron tailings mechanism sand can significantly affect the working performance of concrete;the early strength of C30 iron tailings mechanism sand concrete with a sulfur content of 2%is the highest,and at the curing age of 3 d and 7 d,the compressive strength of the concrete is improved by 14.4%and 11.7%,compared with that of the blank group,and its carbonation resistance and chlorine diffusion resistance are better than that of other sulfur-containing concretes.A small amount of sulfide can provide sufficient SO42-to stimulate the hydration reaction of the cement mix;too high sulfur content will lead to an increase in expansive crystals such as AFt and gypsum in the concrete,which will produce large stresses inside the concrete and cause cracking of the concrete unfavorable to the development of strength at a later stage,for iron tailings mechanism sand concrete,the sulfur content does not exceed 4%is appropriate.

关 键 词：铁尾矿机制砂 硫含量 工作性能 力学性能 耐久性能 微观结构 

分 类 号：TU528[建筑科学—建筑技术科学]