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The article presents a comparison of pozzolanic activity of R-Mud, which is a by-product of TiO2, with known and long-used additives to cement and concrete. Tests were carried out comparing the amount of heat of the hydration of cement and cement with added R-Mud, silica fume, fly ash and trass. The reaction susceptibility of these additives with calcium hydroxide has also been studied using the thermogravimetric method. Results from this method have shown that the reactivity of R-Mud is high and at a similar level to silica fume, while it is much higher than the reactivity of fly ash or natural trass. The high level of pozzolanic reactivity of R-Mud has been confirmed by both isothermal calorimetry and thermogravimetry.

Made up of an engineered mix of ordinary Portland cement (OPC) with artificial pozzolans such as trass, fly ash, and slag, the blended cements have been intensely employed within cementitious materials. The main reasons behind this intensive use can be clarified by enhanced workability/strength, the high resistance to chloride/sulfate, reduced permeability/alkali-silica reaction, and a drop in the heat generated by cement’s hydration. The use of cementitious blends within concrete not only offers durable products but also cuts climate impact by energy saving and falling CO2 emissions. This study presents pozzolanic effect on the hydration heat of cements incorporating fly ash, obsidian, and slag additives. The blended cements were manufactured by three different replacement ratios of 20%, 30%, and 50%. The change in the hydration heat of obsidian-, fly ash-, and slag-based cements was observed by several Turkish standards (TS EN 196-8 and TS EN 196-9). Mortars were used for determining the uniaxial strengths of obsidian-, fly ash-, and slag-based cements. The results show that cement’s hydration heat decreases as the rate of additives (e.g., obsidian) increases from 20% to 50%. The cement’s fineness greatly affects its hydration heat. Increasing the refinement of pozzolanic material to a certain level (30%) leads to an increase in the hydration temperature. After reaching this level, there is no clear relation between the fineness and the replacement rate of pozzolans. As a result, the findings of this work will provide a good understanding of artificial pozzolans on performance and quality of obsidian-, fly ash-, and slag-based cements.

This paper presents a method of utilising ilmenite MUD created during the production of titanium dioxide (TiO2) according to the sulphate method as an additive for Portland cement composites. After the production process, undissolved MUD was additionally rinsed with water and filtrated in the factory to make it more useful (R-MUD) for implementation and also to turn back some of the by-products of the production of TiO2. R-MUD is less hazardous waste than MUD. It has a lower concentration of sulphuric acid and some heavy metals. The rinsing process raised the concentration of SiO2, which is a valuable part of R-MUD because of its potential pozzolanic activity. This means that the R-MUD might be a reactive substitute of part of Portland cement in building composites. The article presents the results of research on the pozzolanic activity of R-MUD and other materials with proved pozzolanic activity, such as silica fume, fly ash and natural pozzolana (trass). Tests were performed using thermal analysis techniques. The tests showed that the pozzolanic activity or R-MUD after three days is at the same level as silica fume and after 28 days it is twice as high as the activity of fly ash. Beyond the 180th day of curing, R-MUD had the same level of activity as fly ash. The summary is supplemented by calorimetric tests, which confirm the high reactivity of R-MUD compared to other commonly used concrete additives, already in the initial hydration period. In summary, heat of hydration after 72 h of Portland cement with R-MUD is at the same level as the heat of hydration of Portland cement with silica fume and also pure Portland cement grout. The results confirm that the process of formation of micro-silica contained in R-MUD react with calcium hydroxide to form the C-S-H phase, which is responsible for the microstructure of cement composites.

Recent fire cases indicated again the importance of fire research. Fast development of construction technology requires new materials. Initiation and development of fire are strongly influenced by the choice of construction materials. In addition to their mechanical properties, their behaviour in elevated temperature is also of high importance. Residual compressive strength of concrete exposed to high temperatures is influenced by the following factors: water-to-cement ratio, cement-to-aggregate ratio, type of aggregate and water content of concrete before exposing it to high temperatures and the fire process. Therefore, mix design and composition of concrete are of high importance for high temperatures. Based on the literature, the fire resistance of concrete is influenced by the used cement type. As regards the cement type, considerable importance has been attached to the various auxiliary materials, such as slag, fly ash, trass, metakaolines and silica fume. There has been no special research devoted to the fire behaviour of pure portland cements. Pure portland cements can be made with various oxide compositions or with different grinding fineness, which increases the resistance of cements to fire. The question arises what effects grinding fineness and oxide composition have on fire resistance of cements. In my experiments, the resistance of portland cements of different composition and grinding fineness to fire (high temperature) were examined. For the test of the solidified cement paste, cement paste cubes of 30-mm edge length were prepared. The specimens were stored in water for 7 days and then in laboratory conditions for 21 days. The cubes of more than 28 days were heated to the given temperature in the furnace and then kept at the given temperature for 2 h (50, 150, 300, 500, 800 °C). Following the 2 h of thermal load, the specimens were examined once their temperature cooled down to room temperature. I have experimentally demonstrated that in case of portland cements, the grinding fineness and aluminate modulus of the cement (i.e. the oxide composition of the cement) have a significant effect on its fire resistance.

The mechanism of the synergic effect of nano-silica and natural pozzolans on the structure of mortar samples in single, binary, and ternary blends was investigated. Mortar mixtures were prepared by replacing 2, 3, and 4% of cement mass with nano-silica and 15% with zeolite, trass or pumice as natural pozzolans with w/cm ratio of 0.485 and flow ranged from 14 to 16 cm. Compressive strength , electrical resistivity, chloride permeability, capillary absorption , and SEM analysis were carried out on mortar samples. Considering the results, nano-silica improved mechanical and durability properties of all mortar samples, but in binary samples, the nano-silica's effect on the mechanical properties improvements in the early ages was more pronounced. Interestingly, in ternary blends nano-silica had remarkable effect even at older ages. Furthermore, the combination of nano-silica and natural pozzolan showed a superior effect on the properties of mortars. As a consequence, the combined positive effect of three-component blends on the compressive strength of control samples was superior to the summation of the progressive effects of nano-silica and natural pozzolans in binary blends. It can be concluded that natural pozzolans amplified the ameliorating effect of nano-silica at older ages (90 days). The synergic effect of components was more pronounced with the increase in the percentage of nano-silica replacement and the selection of more active natural pozzolan. Finally, the ternary blends containing nano-silica and natural pozzolans outperformed the binary ones containing Portland cement and nano-silica not only in terms of reducing costs and negative environmental effects, but also in improving the mechanical properties and durability. Ternary mixtures incorporating 4% nano-silica together with 15% zeolite demonstrated the best results in all tests at the age of 90 days. Compared to the control sample, it improved compressive strength by 51.9% with changing from 48.2 to 73.2 MPa and chloride ions migration coefficient by 570.7% with changing from 16.7 to 2.5 *10 −12 m2/s.

The influence of four naturally occurring mineral additives (zeolite, diatomite, trass and bentonite) on the hydration and properties of cement pastes and mortars was investigated. The materials change the phase composition, heat of hydration (determined by calorimetry) and mechanical properties of composites. After 28 days, the amount of Ca(OH)2 was reduced by up to 23% and up to 35% more C-S-H was formed, as proved by TG measurements. Differences were observed in the kinetics of heat release, especially for 25% of the addition. In the calorimetric curves, an additional exothermic effect is observed, related to the alteration in the hydration of C3A in cement. From the point of view of beneficial influence on mechanical properties of mortars, the additives could be ranked as follows: bentonite &lt, diatomite, zeolite &lt, trass after 2 days and bentonite &lt, diatomite &lt, trass &lt, zeolite after 28 days of curing. The highest compressive strength (58.5 MPa) was observed for the sample with a 10% addition of zeolite. Zeolite, trass, bentonite and diatomite are all pozzolanic materials, however, their activity varies to an extent due to the differences in their specific surface area and the content of the amorphous phase, responsible for the pozzolanic reaction.

Concrete pavement is cost effective and beneficial because of its sustainability and durability. The maintenance and renovation periods for such pavement compared to other pavements are relatively long; however, a significant issue with pavements, especially roller compacted concrete pavements (RCCP), is salt scaling which occurs due to saline solutions such as deicer salts. In the present work, the performance of RCC containing a natural pozzolan called Trass, as a supplementary cementitious material, and an air-entraining agent for salt scaling was investigated. Mechanical and durability tests were performed on specimens containing a water to binder ratio of 0.32, with and without Trass, and an air-entraining agent. It was concluded that, Trass could not improve the compressive and tensile strengths, however, the permeability was improved. Moreover, the amount of mass loss due to salt scaling was not decreased. In all concrete mixtures, using a suitable amount of an air-entraining agent to maintain a total air content of 4.5–5% was found to be necessary for producing RCC containing Trass.

The influence of natural pozzolans on the controlling of the alkali-carbonate reaction (ACR) and the alkali-silica reaction (ASR) has not been studied comprehensively, regardless of the research studies conducted on utilizing natural pozzolans as supplementary cementitious materials. Nevertheless, the performance of natural pozzolans toward the ACR and ASR was investigated in recent studies. The primary purpose of this research is to evaluate the alkali-carbonate expansion of mortar specimens, which contain trass and fly ash in the short-term. For the short-term, the extent of expansion due to ACR was monitored for fourteen 7-day intervals. Based on the test result, fly ash and trass meaningfully reduced the expansion due to ACR in the short-term. Moreover, long-term test results for trass were presented as well. For the long-term, samples were kept at 80 °C in NaOH solution for curing in 56 days according to ASTM C1260 and 390 days according to ASTM C1293 . The observations by optical microscopy have been conducted on thin sections.

Roller compacted concrete pavement is a cost effective and beneficial pavement system which needs fewer material and less energy than other kinds of pavements. An important problem with the pavements is salt scaling that occurs due to a saline solution on cementitious surfaces. In order to reduce the negative effects of salt scaling, the influence of cement replacement by trass, a natural pozzolan, has been investigated. Mechanical and durability tests and salt scaling with air void analysis on hardened concrete were carried out to evaluate the effect of ordinary/trass selected mixes with/without air entraining agents. Results generally showed that although usage of air entraining agents reduced compressive and tensile strengths and increased water permeability and capillary absorption, it performed well against salt scaling in freeze-thaw cycles. The control samples with less w/c performed better than trass samples. In this research, spacing factor obtained about 0.07 mm and 0.1 mm for air-entrained and non air-entrained samples respectively.

This paper presents an investigation into the applicability of the dynamic approach of the Taguchi method to optimize alkali-activated mortar utilizing ground granulated blast-furnace slag and natural pozzolan from Germany called trass (hereafter, AAGT). The volume ratio of powder to alkaline activating solution (Vp/Vaas) was chosen as an input signal, while flow value and flexural and compressive strengths were considered as output values. The concentration of sodium hydroxide solution, mass ratio of sodium silicate to sodium hydroxide solution, ground granulated blast-furnace slag replacement ratio, mixing regime, mixing time, curing temperature, and cumulative temperature in heat curing were taken into account as design parameters. Based on the experiments conducted using an L18 orthogonal array and the calculated results of signal to noise (SN) ratios and sensitivities, input–output relationships between Vp/Vaas and the output values were optimized. Long-term tests on the optimized specimens revealed the applicability of AAGT as a construction material; however, expansion cracks due to a gypsum formation were noticed after long-term immersion in a 10% sulfuric acid solution.

This paper describes the influence of the producing method (inter-grinding and separate grinding) and particle size distribution (PSD) on long term properties of blended cements. Portland cement (PC), limestone and a natural pozzolan (Trass) were used in binary and ternary cementitious blends. In this study, 14 types of cements including two types of Portland cement (PC), four types of Portland-limestone cement (PLC), four types of Portland-pozzolan cement (PPC), and four types of Portland-composite cement (PCC) were used. The results show that for achieving the same percentage of 45-μm residue in blended cements containing Trass, inter-grinding was less energy-demanding than separate grinding (shorter grinding time was required). Also, PPC and PCC provided better durability properties compared to PC and PLC properties. In addition, particle size distribution (PSD) and long term properties of blended cements with same percentage of 45-μm residue were not affected significantly by grinding method. Furthermore, the use of cements with high fineness seems not economically beneficial due to its low effect on long term properties.

Gypsum is one of the additive raw materials added to the clinker grinding process that regulate the binding time of cement or commonly known as a retarder. This research aims to observe the effect of gypsum added variation on the compressive strength of mortar and the whole quality of Portland Composite Cement at plant 14 P.T Indocement Tunggal Prakasa Tbk. The PCC compositions did prepare with a variation of the addition of 0 - 5% gypsum where the clinker ratio did fix at 75%, and two other additives, namely limestone, and trass did add with a fixed ratio of 1.2: 1. The effect of adding gypsum to clinker measured by performing a mortar compressive strength test and the binding time at the ages of 1, 3, 7, and 28 days. The results of series observation and analysis show that composite Portland cement has the most optimal quality in the addition of gypsum as much as 3.5%, where SO3 content is 1.7%, the initial setting time is ≥ 90, and the final setting time is maximum at 375 minutes.

The paper describes the behaviour of tensile joints in irregular external faces of stone walls and the results of laboratory testing of selected technologies for strengthening mortar, which can be applied in strengthening, repair and renovation of historical stone masonry walls, with special references to structures with irregular faces. A research programme of the Building Institute at Wroclaw Technical University on the effectiveness of strengthening irregular, three-leaf stone masonry walls using modern technologies is also presented. Special attention is devoted to technologies introducing stainless steel tie-rods O2 mm in diameter into joints in the external wall face in conjunction with filling joints with trass-based mortar (TUBAG TWM). Results of laboratory testing of plates (40 × 160 × 138 mm) of mortar reinforced with various types of synthetic fibres. Tests were carried out based on a four-point bending, which was treated as representative from the point of view the static behaviour of the reinforced tensile joints in the wall. The possibilities of curtailing the first cracking, strengthening and deflection of the trass-lime mortars are also described, in situations where the stress value exceeds that at which first cracks appear (FSD – first crack, strengthening, deflection). Composites were strengthened with dispersed polymer fibres, steel tie-rods, polypropylene and carbon netting. The analysis indicates that there is a need to identify a hybrid form of reinforcement as an effective solution for strengthening mortars in historical buildings, including joints in historical stone walls.

This paper describes the effect of alkaline activator ratio (Na2SiO3/NaOH) to mechanical properties of geopolymer concrete. The mechanical properties of geopolymer concrete were assessed by setting time, split tensile strength and porosity. Fly ash was used as a cement substitute, and trass used as filler. While, Natrium hydroxide (NaOH) and Sodium Silicate (Na2SiO3) was applied as alkaline activator. In this study, NaOH concentration eight and ten molar with an alkaline activator ratio Na2SiO3/ NaOH by mass: 0.5, 1, 1.5, 2 and 2.5 were used. The test result showed that setting time, porosity and split tensile strength of geopolymer concrete were hardly influenced by NaOH concentration and the alkaline activator ratio. The alkaline activator ratio of Na2SiO3/NaOH has an optimum value at 2 and 2.5. Test result showed that the fastest setting time was 25 minute, the highest amount of closed porosity was 9.035 % and the highest split tensile strength was 2.86 MPa.

This paper describes the influence of the producing method (inter-grinding and separate grinding) and particle size distribution (PSD) on early-age properties of binary and ternary blended cements. Various experiments were carried out to determine properties of cement paste including normal consistency, time of setting, heat of hydration and calcium hydroxide content. In addition, compressive and flexural strength tests were carried out on cement mortars. The results show that for achieving the same percentage of 45 μm residue in blended cements containing Trass, inter-grinding was less energy demanding than separate grinding (shorter grinding time was required). Moreover, PSD and early-age properties of blended cements with the same percentage of 45 μm residue were not significantly affected by the grinding method. Additionally, the hydration reactions of blended cements were slightly accelerated by the increase of fineness value. Furthermore, the use of cements with high fineness is not economically beneficial owing to its low effect on early-age properties.

Composition and microstructure of hardened cement paste have important influences on the properties of concrete exposed to high temperatures. An extensive experimental study was carried out to analyse the post-heating characteristics of concretes subjected to temperatures up to 800 °C. Major parameters of our study were the content of supplementary materials (slag, fly ash, trass) of cement (0, 16 or 25 m%) and the value of maximum temperature. Our results indicated that (i) the number and size of surface cracks as well as compressive strength decreased by the increasing content of supplementary materials of cements due to elevated temperature; (ii) the most intensive surface cracking was observed by using Portland cement without addition of supplementary materials. The increasing content of the supplementary material of cement increased the relative post-heating compressive strength. Tendencies of surface cracking and reduction of compressive strength were in agreement, i.e. the more surface cracks, the more strength reduction.

An extensive experimental study has been carried out to analyse the post-heating characteristics of concrete subjected to high temperatures up to 800 °C. Major parameters of our study were the type and amount of supplementary cementitious materials (slag, fly ash, trass, silica fume, metakaolin) in cements and the level of maximum temperature (50, 150, 300, 500 or 800 °C). Present study includes analyses of surface cracking and residual compressive strength.

This paper describes one of the varying factors influencing the mechanical properties of geopolymer concrete. Fly ash and volcanic material called trass was used as raw materials, while sodium Hydroxide (NaOH) and Sodium silicate (Na2SiO3) was applied as an alkali activator. Mechanical properties were assessed by compressive test, the concentration of NaOH used in this study was eight and ten Molars, and ratio of Na2SiO3to NaOH by mass was 0.5, 1, 1.5, 2, and 2.5. Test results indicated that the strength of geopolymer concrete and binder were hardly influenced by concentration of NaOH in solution and the activator ratio. Binder with activator ratio of 2.5 has the highest compressive strength both in 8M and 10M NaOH system. However, in concrete, there are a few difference, concretes made with 8M NaOH and activators ratio of 2 have the highest compressive strength. This result might due to the low workability of fresh geopolymer concrete. On the other hand, binder and concrete made with 10M NaOH, showed the highest compressive strength when they were made with the activator ratio of 2,5.

This paper describes the influence of the producing method (Inter-grinding or separate grinding) and particle size distribution (PSD) on properties of Portland-pozzolan cements (PPC). Experiments were carried out on cement paste including normal consistency, time of setting, Ca(OH) 2 content, and heat of hydration, on cement mortar including potential alkali-silica reaction, and on concrete including compressive strength, sorptivity, electrical resistivity, and rapid chloride permeability. In this study, 10 types of cements including two types of Portland cement (PC), and eight types of Portland-pozzolan cement (PPC) were used. The results show that PPC provided better mechanical and durability properties compared to PC properties. This was evident especially in PPC containing 25% Trass. Also, the durability properties of cements were not affected by increase of fineness significantly. Particle size distribution (PSD) of PPC varied for each method of production, which was largely due to the amount of Trass in the PPC. Finally, it was concluded that physical properties of cements obtained by Inter-grinding were slightly better than that of separate grinding; however, durability properties were not affected by grinding method. Also, for achieving the same percentage of 45-μm residue, Inter-grinding is less energy-demanding than separate grinding (shorter grinding time is required). In addition, the use of cements with high fineness seems not economically beneficial due to its low effect on long term properties.

WOS: 000443168800003, In this study, the development of hydration of Portland cement and trass substituted cements containing super plasticizer was investigated. The effects of super plasticizer and trass substitution on the compressive strength, water demand, volume expansion and setting time was determined by the experiments the standard cement. Cement pastes were prepared with Portland cement and trass containing super plasticizer were performed using X-Ray diffraction, Fourier transform infrared spectroscopy and Simultaneous thermal analysis in order to determine their the phases developed during the hydration. Furthermore, microstructures by scanning electron microscope 28-days of hydration of cement pastes were determined and cement mortars were examined with strength tests. As a result, with the amount of trass, water needs and setting time have increased and volume expansion values remained between the standards. Also, the amount of Ca(OH)(2) which is formed during the reaction was decreased. All these differences influenced the compressive strength of mortar samples.

This paper presents the results of an investigation on the compressive strength and weight loss of mortars containing three types of fillers as cement replacements; Limestone Filler (LF), Silica Fume (SF) and Trass (TR), subjected to elevated temperatures including 400oC, 600oC, 800oC and 1000oC. Results indicate that addition of TR to blended cements, compared to SF addition, leads to higher compressive strength and lower weight loss at elevated temperatures. In order to model the influence of the different parameters on the compressive strength and the weight loss of specimens, artificial neural networks (ANNs) were adopted. Different diagrams were plotted based on the predictions of the most accurate networks to study the effects of temperature, different fillers and cement content on the target properties. In addition to the impressive RMSE and R2 values of the best networks, the data used as the input for the prediction plots were chosen within the range of the data introduced to the networks in the training phase. Therefore, the prediction plots could be considered reliable to perform the parametric study.

The paper presents the results of a study dealing with the performance of water repellents on hardened blended cement pastes. Since on the European market Portland cement does not play the dominant role anymore and due to the new national and European policies concerning Greenhouse Gases and sustainability, cement manufacturers produce more and more blended cements (CEM II–CEM V). Nevertheless, the majority of experience concerning the efficacy of water repellents is gained from Portland cement; therefore knowledge in regard to the interactions of blended cement with water repellent agent is minimal. Two silane-based products were applied on ‘fresh’ and carbonated cement substrates containing limestone, fly ash, slag and trass, and were investigated in terms of their functionality. The evaluation of the treatments’ performance and effectiveness were assessed using various laboratory measurements. Hydrophobicity, water absorption, colour changes and the penetration depth of silanes into the substrate were evaluated before and after artificial aging experiments. Moreover, the outdoor weathering test was performed to shed light on treated surface appearance in a ‘real’ outdoor environment. The results showed that surface wettability was independent on water ingress or colour variations, especially for cement specimens artificially aged by accelerated carbonation. Cement pastes containing slag and trass seemed to more distinctly affect the water repellents’ surface performance.

The trass ceramisite and ceramisite coated by iron oxide or alumina have been carried out to adsorb the copper (25mg/l) inside wastewater. The results show that the removal rate of trass ceramisite is the lowest, and removal rate of the trass ceramisite coated by alumina is the highest with the removal rate up to 67%. The optimum conditions of Cu 2+-adsorption in wastewater by ceramisite coated by alumina are as follow: pH at 6, contact time for 40min, the amount of adsorbent at 12.5g/l.

This paper reports the use of supplementary cementing materials (SCMs) derived from local resources, for the partial replacement of Portland cement to reduce emission during cement production. Replacement of Portland clinkers up to 20 wt.% with SCMs in normal cements reduced emission by 0.18 kg /kg. The compressive strength exceeded the standard specification for Portland cement ASTM C-150. Blended cement samples containing 20% Portland clinker replacement had compressive strengths of 37 MPa after 28 days of curing time. The microstructure evolution of blended cement at a composition of 80:20 was similar to that of the 100% Portland cement, where the structure between days 28 and 56 reached a steady state. Blended cements with compositions of 70:30 and 60:40 still showed progress of CSH plate formation and the lack of massive structure development. It is shown that the use of supplementary cementing materials could be as one of alternative ways to reduce emissions during cement production.

In the cement industry, high pressure grinding rolls (HPGR) has been used since 1985. At the first applications, this equipment has been installed in the existing cement grinding circuits as an open circuit precrusher in order to crush clinker especially. The cement factories produce different type of cement by using basically clinker, gypsum and additives like limestone and trass. The additives generally are not precrushed before ball mill circuits. In this study, three different mixed feeds were prepared with clinker, gypsum, limestone and trass to evaluate the performance of an industrial scale open circuit HPGR. The results of the tests show that due to the stress concentrates on soft and fractured material, the performance of HPGR becomes worse when the relatively hard material (clinker) is fed together with soft and weak materials (i.e. gypsum, limestone, trass). In addition to the industrial tests, the piston die tests have been also performed with narrow size fractions of the mixed and unmixed materials.

This study is based on the determination of optimum usage of pozzolans as supplementary cementing material for blended cement production. Blended cements were produced with natural zeolite (clinoptilolite), Eskisehir trass, Nevsehir trass, fly ash and ground granulated blast furnace slag at 10, 20, 30, 35, 40 and 45% replacement ratios. Experimental results were also obtained by building models according to artificial neural network and fuzzy logic systems. It is concluded that the strength development of cement mortars containing different pozzolans can be obtained according to neural network and fuzzy logic model test results without any experimental study.

Brick is one of building materials derived from clay. The manufacturing process is with or without the use of substances mixing with the process of combustion at high temperatures. One of the mixing substances is derived from the rind cacao ash and its function is as an adhesive on the bricks.The purpose of this research is to understand the characteristics of brick as effect of cocoa rind as the value of compressive strength, porosity, water absorption and weight of a brick. The main materials of brick production are clays and trass ground which are mixed homogeneous with ratio 1 : 2 by varying cocoa rind ash additional by 5%, 10%, and 15%. The result is the compressive strength of the bricks using rind cocoa ash is 392.2 kg/cm3 higher value than traditional brick is 56.1 kg/cm3.

Natural pozzolans, also known as trass, can be used in cement manufacturing due to their cementitious properties after reaction with calcium hydroxide. At different mixture proportions, the strength, setting time, workability, and soundness of the cement mortar made will differ. In this paper, cement mortars with six different natural pozzolan additions (ranging from 0 to 35%) were employed while using one type of natural pozzolan. As the experimental results show, increase in a natural pozzolan addition decreases the early age strength of cement significantly as expected and decreases the soundness of mortar by two-thirds. In addition, the workability conditions relatively improve and the settings delay for awhile.

In this study, cement mortar samples containing fly ash obtained from Soma Power Plant, two different types of natural pozzolan supplied from Yenisehir and Bilecik and silica fume from Antalya Ferrocrom Industry partial replacement of cement clinker. The strength of the mortars prepared by these mixtures were investigated. The mixtures were prepared by using 10% fly ash and 5% silica fume and the trass contents varied as 30%, 35%, and 40%. Chemical analyses of these mixtures were carried out and Blaine specific surface area values were measured. In performed tests, the highest strength values were noticed in mortars containing natural puzzolan from Bilecik which has high fineness.

The effect of initial water-curing period on the strength properties of concretes was investigated. Three types of cement, one ordinary Portland cement (OPC) and two natural pozzolanic cements (blended and trass cements), were used in the concrete mixtures. Six different curing regimes were applied to the specimens, the first of which was continuous water storing, and the second continuous air storing. In the remaining four regimes, the specimens were stored under varying initial water-curing periods of 3, 7, 14, and 28 days, respectively. The compressive strength tests were carried out on the cubic specimens at the ages of 7, 14, 28, 90, and 180 days. The variation of compressive strength with time was evaluated by using a semilogarithmic function and the strength-gaining rates were calculated by using this equation for different curing conditions. It was found that poor curing conditions are more adversely effective on the strength of concretes made by pozzolanic cements than that of OPC, and it is necessary to apply water curing to the former concretes at least for the initial 7 days to expose the pozzolanic activity. However, when the pozzolanic cement concretes have sufficient initial curing, they can reach the strength of OPC concretes in reasonable periods of time.

The specific rate of breakage (Si) in the widely accepted first-order expression of grinding rate is one of the important factors required to evaluate a grinding process, particularly for the initial grinding stage in various mill types. In this study, the effects of ball diameter and feed size on the specific rate of breakage were investigated on limestone, trass and clinker samples at batch grinding conditions based on a kinetic model. Eight different monosize fractions were prepared between 1.7 and 0.106 mm, using a p 2 sieve series. The specific rates of breakage (Si) were determined from the size distributions at different grinding times, and the specific rates of breakage were compared for three different ball diameters (41, 25.4 and 9.5 mm). The results indicated that the variation of the specific rate of breakage with feed size of cement materials could be expressed. For the specific rate of breakage of each material, empirical equations were developed to express it as a function of feed size and ball diameter. D 2002 Elsevier Science Ltd. All rights reserved.

The relation between 28-day strength of normal cured concrete and accelerated strength is investigated by using an ordinary portland cement and a trass cement under two different accelerated curing conditions, warm water and boiling water. Linear regression analysis was applied on the test results and evaluated by using the efficiency concept, i.e., the ratio of accelerated strength and 28-day normal cured strength. It is concluded that the ordinary portland cement gives higher efficiency than that of the trass cement. The difference due to the cement type is less in the boiling water method than that in the warm water method.

In this article, colemanite ore wastes of particle size

Pozzolan cements are produced by adding pozzolans such as silica fume, rice husk ash, blast furnace slag, fly ash, trass in 20% replacement for Portland cement. On the 28th day of production, the produced specimens are stored in water, in MgSO4·7H2O (5%) solution and in HCl (pH = 2) solution. The strengths and weights were determined after the mortars are stored in solutions for 56 days. Compressive strengths of the mortars stored in water for 28 days are silica fume, rice husk ash, and control, 43.3, 40.1, and 31.0 MPa, respectively. The highest loss of compressive strength is 20% and the highest gain of weight is 4.2%, occurring in blast furnace slag mortar in MgSO4.

A study has been made of the grinding of composite cements produced from clinker and two additional interground additives such as granulated blast-furnace slag, fly ash, trass and limestone. The grindabilities of composite cements depend on the grindability of the individual components. In case of intergrinding the interaction of the individual components plays a positive role. It has been stated that the particle size distribution of the ground products consisting of three components well follow the RRSB-distribution thus enabling this type of distribution to describe them. The particle size distribution of the “composite ground products” depends on their grindability and nature: the easier grindable interground additives promote the formation of wider particle size distribution. For approximately identical composition the fly ash and limestone have more widen particle size distribution than e.g. the trass. The presence of easier grindable components leads to wider particle size distribution and generally to lower mixing water demand. The water demand of composite cements with pozzolanic components is higher, especially in the presence of trass. In order to achieve standard strength the composite cements should be ground finer than the non-blended ones.

The effects on the setting and mechanical properties of partly-refined boro- and phosphogypsum mixed with Portland and trass cements were studied and compared with a Portland cement containing high grade natural gypsum. It was found that the partly refined boro- and phosphogypsum can be used in place of natural gypsum for Portland and trass cements. Reasons for the observed properties of the Portland and trass cements containing the aforementioned chemical gypsum are concluded.

In this study, a comparison of breakage parameters with some porous materials (pumice, trass, and amorphous silica) and the effects on breakage kinetics of powder filling of diatomite were investigated on at batch grinding conditions. For this purpose, first, standard Bond grindability tests were performed for four porous samples. Second, eight different mono-size fractions of all samples were carried out between 1.7mm and 0.106mm formed by a a?2 sieve series. Then, Si and Bi,j equations were determined for the size distributions at different grinding times, and the model parameters (Si, aT, ?, ?, ?j, and ?) were tested for four different porous materials. Finally, model parameters were discussed for four different powder filling (3.5, 7, 10.5, and 14%) of diatomite samples. From the results of test, the validity of the relationships between Bond grindability and breakage parameters has been not confirmed with good correlation coefficients. The reason of this negative result could be attributed to different of the geological origin of porous materials. In addition, the results of the effect of powder filling on the grinding were found different than other investigators. Copyright © Taylor & Francis Group, LLC.

Borogypsum is a by-product of a boric acid factory. Approximately ninety thousand tons per year are produced by two boric acid factories in Turkey. The borogypsum consists primarily of CaSO4·2H2O, secondarily of B2O3, and some other impurities. In this work, the use of borogypsum as an additive in cement production was studied. For this, the proportion of B2O3 in borogypsum was gradually decreased by water extraction. Refined borogypsum was mixed with Portland and trass cements and its effects on the setting and mechanical properties of these mixes were studied. It was concluded that refined borogypsum can be used for Portland and trass cements.

The ash of the retort residue of the oil shale from central Jordan has been further tested to evaluate its pozzolanic activity. According to the preliminary experiments the ash had cementive properties. Thermogravimetric analyses were performed on ash, cement, ash blended cement and ash-lime pastes. In the blended pastes, addition of ash seemed to decrease the amount of lime generated. In the ash-lime paste the lime consumption by ash with time followed a similar trend to the reactions of trass and silica fume with lime. The ash-lime reaction was mainly a diffusion controlled process obeying the Ginstling-Brounshtein equation. The pozzolanic activity of the ash, as indicated by its lime activity and rate constant, was not as high as the other pozzolans compared, mainly due to its lower fineness. Tests on compressive strengths of cement and lime mortars blended with ash confirmed the findings, indicating that up to 20% of cement could be replaced by ash used as an admixture. Ash-lime mortars could gain moderate strengths under accelerated curing, suitable for some building units.

As part of a comprehensive research project on the durability of on and offshore concrete structures in the Persian Gulf, a simulation laboratory has been made use of. The present study consists mainly of nine month exposure tests in the tidal and atmospheric zone conditions in the laboratory. Concrete specimens containing different supplementary materials, namely silica fume, blast-furnace slag, diatomous earth and trass, have been thoroughly investigated. The tests conducted include compressive strength, volume changes, half cell potentials, carbonation, and chloride diffusion, all at different ages. With respect to the alternate cycles of wetting and drying, the superior performance of silica fume was followed by the diatomous earth pozzolan. However, all concrete mixtures containing natural and artificial pozzolans showed better performance when compared with the plain portland cement control concrete mixtures.

Phosphogypsum, the by-product of phosphoric acid manufacture, is considered as a gypsum for the control of the setting time of Portland cement and trass cement. However, it is well known that impurities, usually included in phosphogypsum, injuriously affect the hydration of cement. The object of this paper is to clarify the characters of impurities in phosphogypsum produced in Turkey and to obtain refined phosphogypsum using various methods following IR technique.

The simultaneous size reduction and solvent extraction of canola seeds were studied using a laboratory blender and a small, pilot-scale Szego mill. The laboratory tests established that over 95% of the oil may be removed from the seed in a single contact stage. The effects of contact time and solvent-to-seed ratio were investigated. The extraction equilibrium favored the extraction of the oil at higher solvent-to-seed ratios. In all cases the extraction reached some 90% of the equilibrium value after 3 min. Runs in the Szego mill, which is a unique orbitalmill developed by one of us (O. Trass), confirmed that solvent grinding is an efficient extraction technique. In this equipment, contact times as short as 30 sec give significant extraction, with the system approaching equilibrium in one minute. The Szego mill appears to be suitable for the rapid extraction of edible oil seeds such as rapeseed.

whole foundation or its spalled-off part along the perimeter. As the result of concrete shrinkage, an inward squeezing of the damaged parts of the foundations occurs along the yoke perimeter during the hardening process. The effectiveness of the stressed yokes is determined, not only by virtue of the simple increase in section and the transfer of loadings from the existing to the new part of the foundation but also primarily through joining the cracked parts into a single whole and putting them back into service. The inward squeezing also provides a reliable joining of the existing foundation concrete and the new, strengthening concrete, into a unity performing as a single whole, and it is therefore essential during the design phase to provide for an increased hardening shrinkage of the concrete and to take measures against the formation of shrinkage cracks; and, in carrying out the work, to ensure the necessary inward squeezing. An increase In the hardening shrinkage of concrete can be secured either by keeping the water/cement ratio constant but increasing the plasticity of the mix, i.e., the cement content compared with the design value; or, without changing the cement content, to raise the water/cement ratio to the maximum. However, in this case concrete strength is reduced and this requires the use of a high standard of cement. In order to increase the hardening shrinkage of concrete it is necessary to use rapid-hardening (quick-setting) cements and possuolanic (trass) cement, and also to include hydraulic additives and hardening accelerators in the mix, in quAntities recommended for their principal designation. This is also promoted by limestone and dense sandstone aggregates: During their slow absorption of water in the hardening process of the concrete, a practical reduction of the water/cement ratio, i.e., an increase in concrete strength, occurs.

The effect of two calcareous fillers (ground limestone and reagent quality CaCO 3 ) on the compressive strength of Portland cement, was studied and compared with the corresponding effect of two pozzolanic fillers (ground scoria and Rhine trass) and one non-calcareous, non-hydraulic filler (reagent quality CaF 2 ). It was concluded that fillers affect strength through their accelerating effect on the cement hydration. This effect was found to be essentially the same for all the fillers studied irrespective of their specific chemical composition. It was also concluded that the formation of calcium carboaluminate, if it took place when calcareous fillers were involved, did not necessarily affect the cement compressive strength. Further tests are being carried out to show that the use of fillers is, indeed, associated with an increased rate of hydration.