Durability Of Rock Research Articles

Engineering Characterization of Rocks from Selected Quarries in Abuja, Nigeria.

The study aims to understand the strength, durability, and suitability of Abuja rock for planning, design, and construction of engineering projects. Three quarries in Abuja (Kubwa, Mpape, and Lugbe) were selected, and four samples were observed to be the most dominant, covering 90%-95% of the rock used in manufacturing aggregates for engineering construction. Geotechnical engineering properties of these rocks were analyzed in an engineering laboratory. Experimental tests included uniaxial compression test, Schmidt hammer rebound test, Los Angeles Abrasion test, Water absorption/moisture content test, and Specific gravity test. The compressive strength ranges from 21.32Mpa to 28.91Mpa, classified as sedimentary rock with moderate hardness. Schmidt rebound numbers range from 21.94 to 35.28, providing immediate access to rock strength. This shows on correlation with R²= 0.409 means the uniaxial compressive strength value is nearly proportional to the Schmidt rebound number. The specific gravity and water absorption relationship showed a negative correlation, with values of 2.43, 2.32, 2.32, and 2.28 on specific gravity and 0.15%, 0.22%, 0.20%, 0.17% on water absorption/water content from porphyritic granite, porphyroblastic gneiss, biotite granite, and granite gneiss, respectively. It shows in a correlation that water content is inversely proportional to the specific gravity with value of R²=0.400. Los Angeles abrasion values were within the allowable range (20-30) which reveals values from 21.00 to 23.00. The study reveals that the engineering characteristics of the sampled rocks are within the standard range for construction purposes. Porphyritic gneiss and granite gneiss are suitable for building and road construction due to their higher compressive strength and low water absorption, providing good strength and durability under different prevailing environmental conditions.

Stones that stand the test of time: exploring the durability and weathering of metamorphic Rocks of Sri Lanka

Weathering and durability are the key properties of the rock to evaluate the suitability and end-use for different kinds of applications such as building and construction material and engineering structures. Weathering is simply known as the alteration or breaking down of rocks due to air, water, etc. whereas durability of rock can be defined as the ability to resist the weathering to maintain the characteristics of strength under various environmental conditions. To evaluate the strength of rock, the degree of weathering and durability can be used as main indicators[1] as the measure of strength depends on the external force resistance.

The disintegration mechanism analysis of soft rock due to water intrusion based on discrete element method

Though many laboratory tests have been carried out on the effect of water content on the disintegration characteristics of soft rock, there are still relatively few numerical simulations that can well describe this kind of process. Based on the test results obtained by previous relevant research, the two-dimensional unconfined soft rock immersion test was numerically simulated by the discrete element method. The hydration expansion of clay particles is considered in the simulation. The breaking force and residual strength coefficient in MatDEM are selected to characterize the slaking durability of soft rock. Several groups of control sample models were set up, and the effects of crack, clay mineral content, and initial water content on the softening process of rock samples were discussed. The results show that the simulation in this paper is consistent with the process of infiltration and disintegration of soft rock after water immersion in relevant studies. The strength parameters show an exponential attenuation relationship with water content. The breaking force and residual strength coefficient of the complete sample change in a gradient from outside to inside with water content. In addition, the initial crack improves the permeability of soft rock samples and changes the distribution of water content, which has a significant effect on the slaking durability of soft rock. Soft rock samples with high clay mineral content are more prone to plastic softening. The slaking durability of soft rock decreases as the initial water content increases.

Hyperalkaline seepage water and the accompanying carbonate deposits from the grouted foundation rock of a rock-fill dam

The inspection gallery of a dam is leached by reservoir water that has infiltrated through the rock-fill dam body from the high-pressure water area upstream (leakage), and groundwater seeping through the foundation bed which has been injected with ordinary Portland cement (OPC) grout. Seepage waters with a pH greater than 12 are characterized by the major components of Ca(OH)2 and alkali hydroxides, lower Mg2+ concentration and higher K+/Na+ molar ratio than those for river and spring waters and groundwater near the dam site, and the extensive carbonate deposits precipitated from the waters. During a low discharge period, NaOH was the major component because Ca2+ was removed as carbonate deposits. Based on the stable isotope ratios of hydrogen and oxygen in the water, which reflect the altitude effect, it was inferred that the seepage waters are supplied from the shallow groundwater near the dam site and that the leakage is a mixture of the seepage water and reservoir water. Alkali hydroxides and Ca(OH)2 cement porewaters formed during the early stages of hydration of OPC are still present in the cement mass after 46 years, and that the OPC still remains partially unhydrated. These highly alkaline porewaters have seeped through gaps of the concrete joint surfaces to discharge into the inspection gallery. The Ca(OH)2 concentration in the seepage was below the portlandite saturation, therefore, the grout-derived solutes are considered to have been diluted as they diffused into the shallow groundwater before being discharged with the groundwater seeping into the gallery due to the hydraulic head difference and mixed with the groundwater. Ca(OH)2 in the seepage reacted with atmospheric CO2 in the inspection gallery, and the carbon stable isotope ratio of the carbonate deposits produced in this way was unusually low, about −25‰ VPDB, due to the large disequilibrium isotope fractionation during the direct reaction of CO2 with OH− in the solution. In addition to the change in its discharge, the hyperalkaline seepage and the resulting carbonate deposits with unusually low δ13C values can be measures of the durability of the grout-treated foundation rock of the rock-fill dam, because the decrease in pH in the future is related to the instability of the grout hydration products by carbonation.

Durability prediction of brittle rocks based on type-I crack extension theory

When subjected to long-term static loading, with the accumulation of damage and fracture, brittle rock would fails when the static loading is lower than the compressive strength of the rock, and the increasing of the static loading can generally shorten the time required for the brittle rock failure. To explore the relationship between the durability of the brittle rock and the applied static loading, in this paper, the propagation modes of the microcracks in brittle rock under the static loading in the subcritical crack growth stage are uniformly attributed to the tensile mode, and the total time required for microcrack propagation in the subcritical crack growth stage is chosen as the criterion for judging the durability index of brittle rock. Based on the Maxwell model, the local effective tensile stress that drives crack propagation is derived. The phenomenon of brittle rock exhibiting tensile failure under the compressive stress is preliminarily explained, and the corresponding requirements for this phenomenon to occur are also presented. A new expression of rock durability prediction with a clear physical meaning is established. The key parameter, i.e., the durability index “n” in the newly derived expression is obtained through fitting, and the relationship between the durability index and the rock type is preliminarily analysed. This study may provide an approach for preliminarily estimating the durability of brittle rock.

Assessment of durability and deterioration of rocks from western Iraq

The behavior of rocks in water can be expressed in terms of their ability to resist slaking when exposed to water. This ability to withstand durability and deterioration from weathering affects both the effectiveness of the engineering project and its cost. Durability and deterioration of rock from the west of Iraq are little studied, and there is little confidence in these properties to be utilized in engineering works. This study is emphasized on the information obtained from the slaking durability test, specific gravity, and absorption tests performed to evaluate durability and deterioration properties of the rock samples taken from the stratum of the Rutba-Jezira Zone, western Iraq. An examination of the statistical relationship between water content, slake durability index, specific gravities and absorption was also included. The results show that the durability and deterioration of the investigated rock are variable due to the occurrences of a different secondary constituent. Such rock can deteriorate rapidly upon exposure or slake and soften when in contact with water. As a result, the rock of the study area is problem material in several phases of geotechnical engineering.

Effects of Mineral Composition and Texture on Durability of Sulfate Rocks in Gachsaran Formation, Iran

Slake Durability is one of the most important engineering properties which is investigated by many researchers. Several correlations have been proposed between the slake durability index (SDI) of some rocks and their engineering properties. The purpose of this research is to determine the SDIs of sulfate rocks, including gypsum (GP), anhydrite (AN), and clay bearing gypsum and to investigate the effect of mineral composition and rock texture on the SDI. In order to carry out this research study, rock blocks were collected from the outcrops of the Gachsaran formation in 4 under construction reservoir dam sites in Iran. Rounded rock samples were prepared according to standard methods. Due to the specific characteristics of sulfate rocks, a thorough research was carried out on the determination and application of appropriate drying and saturation methods of sulfate rocks. The slake durability tests were performed in 5 cycles of 10 min using ionized water under dry and saturated conditions. These experiments have shown that in a rock composed of GP and AN, the durability of a rock is affected by its mineral composition and as a result, the durability index in both dry and saturated conditions decreases with increasing the GP percentage, and inversely, increases with increasing the AN content. In an almost pure GP or AN rock, there is a strong linear correlation between the number of slaking cycles and the SDI. Presence of clay-sized carbonates or microcrystalline carbonates in the mineral composition of GP rocks, increases the durability of rock in both dry and saturated conditions, especially in higher test cycles. Rock texture also has an important effect on the durability index, so that in a similar mineral composition, a rock with a porphyry texture is more durable than a rock with alabaster texture.

Effect of Microstructure on Frost Durability of Rock in the Context of Diagnostic Needs

Problematic rock classification criteria used in civil engineering require correction. Particular attention should be paid to frost resistance test methods and criteria of acceptable absorption levels. The classification of frost resistance levels may be incorrect due to insufficient number of freeze-thaw cycles, and the criterion of rock absorption is inaccurate. Based on the results of research completed to date, the authors conclude that all rocks with capillary volumetric absorption below 0.6% are highly frost resistant, regardless of their origin. All rocks with capillary volumetric absorption above 1.5% are not frost resistant to a greater or lesser degree. Rocks with capillary volumetric absorption between 0.6% and 1.5% may show both low and high frost resistance. This group of rocks is characterized in this article. The structural features compared include mineralogical composition (derivatography and X-ray analysis), appearance and size of crystallite (analysis with an optical microscope, and SEM). The texture features evaluated include total porosity, pore size distribution MIP, capillary water absorption, vacuum absorption, and the degree of filling the pores with water. It has been found that increasing the number of freeze-thaw cycles allows better assessment of the rock's potential durability. The capillary water absorption in combination with the degree of filling the pores can be an effective durability indicator for use in the classification of rock construction products.

Mineral Compositions and Micro-Structural of Epoxy-Repaired Rock Revealed by X-ray Diffraction and Scanning Electron Microscopy

In order to improve the mechanical properties of rock with lots of cracks, this study adopts electronic methods (X-ray diffraction and scanning electron microscopy) to determine the mineral compositions and micro structural characteristics of epoxy-repaired rock. Fractured rocks with low strength or high permeability may not be appropriate for dam foundation. The strength and durability of fractured rock are increased after chemical grouting. Test results show that, some of the cracks and voids are repaired by epoxy particles, resulted in the decreasing rock porosity. The proportion of epoxy resins is about 3.5%-5.5%, showing a discrete distribution and can not connect with each other.

Study on the Durability of Poor Rock as Internal Aggregate for Cncrete of Dame

Study on the Durability of Poor Rock as Internal Aggregate for Cncrete of Dame

Slake durability study of shaly rock and its predictions

More than 35% of the earth’s crust is comprised of clay-bearing rocks, characterized by a wide variation in engineering properties and their resistance to short term weathering by wetting and drying phenomenon. The resistance to short-term weathering can be determined by slake durability index test. There are various methods to determine the slake durability indices of weak rock. The effect of acidity of water (slaking fluid) on slake durability index of shale in the laboratory is investigated. These methods are cumbersome and time consuming but they can provide valuable information on lithology, durability and weather ability of rock. Fuzzy set theory, Fuzzy logic and Artificial Neural Networks (ANN) techniques seem very well suited for typical complex geotechnical problems. In conjunction with statistics and conventional mathematical methods, a hybrid method can be developed that may prove a step forward in modeling geotechnical problems. During this investigation a model was developed and compared with two other models i.e., Neuro-fuzzy systems (combination of fuzzy and artificial neural network systems) and artificial neural network system, for the prediction of slake durability index of shaly rock to evaluate the performance of its prediction capability.

Methods for Predicting Shale Durability in the Field

Abstract Durability of shales and other weak rock is an important parameter describing the material's susceptibility to breakdown upon exposure to water or during construction work. While laboratory methods have been developed to measure durability, no correlations between laboratory results and simple field tests have been determined. The results of this study show that certain field parameters can predict slake durability with acceptable accuracy. The recommended field tests, in order of desirability, are slake index, jar slake, hammer rebound, and NGI “Q” value. Single variable and multiple variable linear regression equations are given, including equations conservatively modified so that 95% of the slake durability values are underpredicted.

The effects of freezing conditions on rock breakage

It was observed that the efficiency of some autogenous grinding circuits was dependent on temperature, with the energy-efficiency of the grinding process decreasing in the winter months, accompanied by an increase in critical-size production. Several possible causes of this phenomenon were suggested, including: To determine which mechanisms were occurring, drop tests were carried out using frozen and unfrozen rock with varying degrees of porosity, both dry and water-saturated, and which had been blasted for mining in summer and in winter. These tests showed that there was no difference between the summer-blasted ore and the winter-blasted ore, and that durability changes in dry rock over the temperature range from 25 °C to −25 °C were negligible. However, water-saturated rock showed an increased resistance to breakage upon freezing, particularly when the rock was highly porous, or when a layer of ice formed on the surface. Seasonal changes in the durability of rock in grinding are therefore due to formation of ice in and around the rock.

Durability of carbonate rock as building stone with comments on its preservation

Carbonate rocks have been extensively used as building stones because of their availability, workability, and attractiveness. Unfortunately, however, some stones suffer from chemical attack or freeze-thaw activity. The environmental affects, especially those due to pollution of the atmosphere, are discussed in terms of weathering processes, salt crystallization, and acid deposition. A review of some recent research in relation to deterioration of stone in urban environments is given and carbonate rocks are classified in relation to position within a building, geographical location, and degree of pollution. Some comments on stone preservation are provided, especially in terms of the properties a preservative should possess.

Durability of Rock as Function of Grain Size, Pore Size, and Rate of Capillary Absorption of Water

A series of experiments were performed to determine the relationship of grain and pore size to the capillary absorption of rock and the level to which water will naturally penetrate when the rock is exposed to it. As expected, the fine grained rocks showed the fastest rate and highest penetration of water and salt solution. Rates were found to be log-normally distributed—fast initial absorption, slower subsequent absorption. A correlation was found between rates of absorption and durability. High rate of absorption specimens were less durable during freezing and thawing than rocks with a low rate of absorption. All other conditions, such as mineralogy and environment, being constant, it is concluded that finer grained rocks, because of their more rapid water and salt solution intake, tend to deteriorate and weather faster than coarser grained equivalents. The results indicate the importance of grain size and pore size in assessment of the long term durability of rock when used as construction material.

Some preliminary considerations on the selection and durability of rock and concrete materials for breakwaters and coastal protection works : Fookes, P G; Poole, A B Q J Engng Geol, V24, N2, 1981, P97–128

Some preliminary considerations on the selection and durability of rock and concrete materials for breakwaters and coastal protection works : Fookes, P G; Poole, A B Q J Engng Geol, V24, N2, 1981, P97–128

Some preliminary considerations on the selection and durability of rock and concrete materials for breakwaters and coastal protection works

Summary The durability of concrete and rock used in marine construction is reviewed. The marine environment has been divided into four significant zones of effect on the durability of concrete and rock. Forms of deterioration specific to concrete or rock and common to both are discussed in the context of the four zones. Rates of concrete deterioration in the zones and in different environments are also discussed. A preliminary study is presented of the shape, size and weathering characteristics on the performance of rock used in marine structures, particularly rubble-mound breakwaters. Nomographs for field use, relating the design weight of rock to shape, size and specific gravity are presented and acceptance and compliance tests for assessing suitability of rock are suggested. Design of filter systems is also considered in relation to rock characteristics for breakwater cores with high fines contents and for reclaimed areas behind coarsely graded protection works.

Engineering petrology for roads in South Africa

The thirty different types of rock used by engineers in South Africa for road construction are described and the suitability of these rocks, and their weathering products, for road construction is discussed in the light of the South African geology and climate. Unconsolidated windblown sand, alluvial deposits and soil are not included. The thirty types of rocks are divided into nine groups according to their petrological and road engineering properties. In some cases this grouping cuts across the traditional genetic classification of rocks. Special attention is drawn to the importance of quartz in determining the quality and durability of rock to be used as aggregate in road construction.