中国水泥行业节能减排措施的协同控制效应评估研究

水泥行业是温室气体与局地污染物协同控制的重点行业。以往该行业的协同控制评估或针对个别企业,或采用自上而下和自下而上模拟模型结合情景分析评估行业协同减排效益,尚缺乏系统评估水泥行业全系列节能减排措施（或技术）协同控制效果的研究。文中首先测算水泥行业24项节能减排措施综合大气污染物协同减排量,再通过协同控制效应坐标系、交叉弹性、单位污染物减排成本等评估指标和方法,对这些措施开展协同控制效果评估。结果表明大多数节能减排措施可协同减排局地大气污染物;协同减排潜力最大的是结构调整措施;能效提升与节能措施的协同减排成本较低,但减排潜力有限。本文强化了水泥行业节能减排措施的协同控制效能特性分析,可为水泥行业开展协同控制路径规划提供参考。     

Primary yielding locus of cement-stabilized marine clay and its applications

ABSTRACT

Strength and stiffness properties of materials are widely studied and used in civil engineering practice. However, most studies are based on unconfined conditions, which are different from real status of soil. This study investigated the primary yielding and yield locus for cement-stabilized marine clay. In this study, two types of cement-stabilized soils were studied through isotropic compression, triaxial drained shearing, unconfined compression, and bender element testing. Specimens with 20–50% of cement content and 7–90 days of curing period were used for the tests. Stress–strain behavior and primary yielding were evaluated, followed by construction of the primary yield locus. The characteristics of the primary yield locus and its development with curing time then were studied. The results showed that the properties of the primary yield locus were dependent on the type of stabilized soil, but were independent of the cement content and curing period. Thus, the approach provides a way to estimate the primary yield stress and drained stress path before primary yielding for cement-stabilized soil under confined condition. An empirical function was used to fit the primary yield locus. The primary isotropic yield stress was correlated to unconfined compressive strength or maximum shear modulus. Three indirect methods were proposed to predict the primary yield stress for cement-stabilized marine clay. The results showed that the primary yield stress can be estimated with reasonable accuracy.     

Long-term immobilisation of Cd2+ at the Tulul Al Hammam natural analogue site,central Jordan

The Tulul Al Hammam area in central Jordan is a natural analogue site where to study long-term Cd²⁺ retention during the weathering of Cd-enriched combustion-metamorphic marbles with clinker-like mineralogy. Natural Cd-rich portlandite (Ca_0.67−0.45Cd_0.33−0.55)[OH]₂ was discovered and characterised by single-crystal XRD, SEM/EDS, and microprobe analyses, and Raman spectroscopy. The Ca[OH]₂ – Cd[OH]₂ solid solution ((Ca_1−xCd_x)[OH]₂) is isostructural with Ca[OH]₂ and β-Cd[OH]₂ crystals in the CdI₂-type of structure. Cd-rich portlandite is a common secondary phase in slightly altered massive marbles, where it replaces and rims single-crystals of the high-temperature precursor (Ca_1−xCd_x)O. The Cd:Ca molar ratios of (Ca_1−xCd_x)[OH]₂ are inherited from the precursor phase (Ca_1−xCd_x)O. Reliable long-term immobilisation of Cd in (Ca_1−xCd_x)[OH]₂ is assumed for pore water pH values from 10.5 up to 12 buffered by C-S-Hs formed mainly during spurrite hydration. The Tulul Al Hammam site may have some bearing on long-term Cd²⁺ retention in the concrete matrix.     

连续胶结声速理论胶结半径表达式的一般性推广及应用

针对Dvorkin 和Nur （1996） 提出的连续胶结声速理论（CCT）中的胶结半径表达式仅适用于孔隙式胶结疏松砂岩的局限性,通过胶结物与颗粒之间的空间几何关系,在胶结物中心厚度不为零的前提下,推导了胶结物胶结半径的一般表达式,并考察了胶结物中心厚度对疏松砂岩声波速度的影响,探讨了该表达式在基底式胶结疏松砂岩纵横波速度预测中的应用.结果表明：随胶结物中心厚度变大,纵、横波速度均减小,且孔隙度越大,胶结物含量越少,速度下降越快;孔隙度或胶结物含量不变时,纵横波速比随胶结物中心厚度的增大而增大;纵横波速比随孔隙度的变化规律与胶结物中心厚度有关,当胶结物中心厚度较小时,孔隙度增大,纵横波速比略微减小,而当胶结物中心厚度较大时,孔隙度的增大会引起纵横波速比略微增大;对于基底式胶结疏松砂岩,使用推广后表达式修正的CCT模型相对原CCT模型能够更好地预测其声波速度,同时发现,利用其纵横波速比无法预测由孔隙度或胶结物含量变化引起的疏松砂岩软硬的变化,但是在胶结物含量或孔隙度不变的情况下,纵横波速比可指示由胶结物中心厚度变化引起的疏松砂岩软硬的变化.     

充分利用地质档案优选水泥原料矿山

优选云南水泥原料矿山,对水泥工业持续发展有重要意义。根据多年从事地质档案管理经历,充分利用、发掘地质档案资源信息,整理、研究、统计了云南水泥原料矿产资源的分布状况,优选部分水泥原料矿山,为本省水泥原料矿产资源规划、水泥工业持续发展和投资决策服务。     

Evaluating the stiffness of chemically stabilized marine clay

Cement-stabilized clay is widely used in soft clay improvement for deep excavation, underground construction, and land reclamation. This paper presents a study on the evaluation of elastic modulus for cement-stabilized marine clay. First, two types of cement-stabilized soils were studied through isotropic compression tests and cylinder split tensile tests. Specimens with different mix ratios and curing periods were used. Stress–strain behavior under isotropic compression was discussed, followed by an introduction and estimation of the stress-free bulk modulus. Empirical correlations between elastic moduli and functions for estimating elastic moduli were then proposed. Further estimation of elastic modulus was conducted with another data set. The results showed that the proposed function for estimating elastic modulus is effective for cement-improved marine clay. Finally, the proposed method and empirical functions were validated with other types of cement-stabilized clay.     

泥质砂岩中接触胶结泥质定量估算及对砂岩弹性的影响

在泥质砂岩的岩石物理建模中,明确泥质砂岩中泥质胶结物的接触类型及其含量对正确认识泥质的胶结作用对泥质砂岩声速的影响以及合理地建立岩石物理模型至关重要.现阶段,尚未有实验室定量估算胶结泥质的方法,导致应用胶结砂岩理论模型预测胶结砂岩地层的声速时往往由于胶结物含量被高估从而导致预测声速结果偏高.本文通过观察铸体薄片中泥质与颗粒之间的接触关系和相对分布提出了一种区分胶结泥质和分散泥质的方法：与两个或两个以上颗粒接触的连续分布的泥质为胶结泥质;与一个颗粒接触或者不与颗粒接触的泥质为分散泥质.基于这一准则,本文基于像素拾取法估算了人造泥质砂岩的胶结泥质含量,并将胶结泥质含量作为胶结砂岩模型的输入参数优化CCT模型.对比原始模型,本文方法声速误差下降了20%,预测准确度显著提高.本文方法适用于弱胶结地层的岩石物理建模,能够准确的预测声速以结合地震和测井资料识别有利储层,定量评价储层参数.

     

Speciation of heavy metals in cement-stabilized waste forms: A micro-spectroscopic study

Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of industrial and radioactive waste in underground repositories. In this study, synchrotron based-techniques (micro X-ray spectroscopy (XAS) and micro X-ray fluorescence (XRF)) were used to investigate Co and Ni uptake by Hardened Cement Paste (HCP) with the aim of improving our understanding of the immobilization process of heavy metals in cement at the molecular level. For Ni and Co, XRF mapping revealed a highly heterogeneous element distribution as far as the concentration is concerned. The XAS studies further showed that Ni(II) forms predominantly layered double hydroxide (LDH) phases. In contrast to Ni, Co was found to be present in the oxidation states II and III. Co(II) is predominately incorporated into newly formed Co(II) hydroxide-like phases (Co(OH)₂), Co-LDH or Co-phyllosilicates, whereas Co(III) tends to be incorporated into a Co(III)O(OH)-like phase or a Co-phyllomanganate.     

岩质边坡相似材料导热系数的试验研究

基于相似材料配比的正交试验方案,制备了不同成分和配合比的相似材料试样,量测了各试样的导热系数值,研究了相似材料中含水率、胶结物及砂胶比等变化对导热系数量值的影响。研究结果表明:由于水和空气的导热系数差异较大,试样中含水率变化对导热系数量值的影响显著; 胶结物在试样中所占比例小,其成分因水化引起的孔隙率变化有限,胶结物成分和配比变化对导热系数量值的影响可以忽略; 受砂与胶结物之间的相互作用,胶结物成分和配比方案将改变砂胶比对导热系数量值的影响。当胶结物成分为石灰和石膏时,影响导热系数值的因素依次为含水率、砂胶比和胶结物,并随着砂胶比的增大,导热系数值在增加,但增幅逐渐减小; 当胶结物成分为水泥和石膏时,影响导热系数值的因素依次为含水率、胶结物和砂胶比,但随着砂胶比的增大,导热系数量值变化可以忽略。     

Assessment of the industrial utilization of scoria materials in central Harrat Rahat, Saudi Arabia

Although basaltic volcanic scoria deposits are widespread in and around the scoria cones present in the Harrats, very few occurrences have been evaluated and still fewer have been exploited. The scoria from a quarry in central Harrat Rahat was investigated and assessed for its industrial utilization. Cubes were prepared from several concrete mixes using scoria as lightweight coarse and fine aggregates in different percentages. The compressive strength values of the cubes were found to be acceptable and satisfy the ASTM (1995) requirement for structural concrete. The scoria was also assessed for its utilization as a cement additive. Pozzolanic activity was tested according to the Italian standards and found to be acceptable. The strength activity index with Portland cement and the effectiveness of scoria admixture in controlling alkali-silica reactions were tested according to ASTM (1995) standards. Mortar cubes were specially prepared for these studies using different mixes and different storage procedures. The results satisfied the ASTM (1995) requirements as cement additive. The utilization of scoria as a heat-insulating material was tested and the results were found to satisfy the ASTM (1995) requirements. This fact suggests it could be utilized in the manufacture of the building blocks. It is recommended to evaluate the other scoria deposits, exploit the economically feasible ones and utilize them for different industrial applications. The manufacturing of heat-insulating concrete or building blocks using scoria is of prime importance as an energy saver.