Characterization of building stones from the ancient Tyana aqueducts,Central Anatolia,Turkey: implications on the factors of deterioration processes

Many archaeological and historical monuments constructed by different civilizations over the last 5500 years can be observed in the Ni?de region located in central Anatolia. The Tyana aqueduct as a continuation of the Roman Pool is one such important historical monument. The aqueducts that carried the water of the Roman Pool to the ancient city of Tyana were constructed during the time of the Roman emperors Trajan, Hadrian and Marcus Aurelius Antoninus. Half of the total length of the aqueducts (3 km) is on the surface and the rest is buried. The engineering properties of the rocks used in such archaeological and historical buildings are very important in terms of conserving these structures for future generations. In this study, the geomechanical and geotechnical features of the Tyana aqueducts were investigated to understand the rock types, deterioration in the stones over time and problems originating from these features. Also, for restoration purposes, the ancient stone quarry areas for the aqueducts were identified, and the chemical, petrographical and geomechanical properties of fresh travertine blocks from these quarries were determined. The main rock type used as building stones in the aqueducts is Mio-Pliocene travertine. Laboratory studies were performed to determine the mineralogical, petrographic and petrophysical properties of the building stone samples. Fresh and used travertine samples were composed exclusively of calcite crystal. The results of chemical analyses were similar for fresh and used travertine samples. To determine the geomechanical properties of the travertines, dry unit weight, water absorption, effective porosity, P-wave velocity, Böhme abrasion test, capillary water absorption and uniaxial compressive strength experiments were conducted. In addition, Schmidt hammer hardness measurements were performed on site for the different levels and different textural characteristics of the belts on the travertines. According to the experimental data obtained, higher strength was displayed by samples with fine grains, massive texture and low porosity. The deterioration effects in most of the travertines used in the original structure are very low. In addition to human effects, the use of small stone dimensions (especially the stones used in belts as keystones) and the use of stone from the same quarry but with features that differ or are inferior are thought to be factors in the destruction of the Tyana aqueducts.     

Dynamics of capillary water absorption in natural stone

Two natural carbonate stones from Croatia (Kirmenjak avorio and Veselje unito) were analyzed to assess their properties for use in masonry buildings. The results indicated considerable differences in the water absorption (expressed in g/m²) shown as a function of elapsed time. The petrographic analyses highlighted different characteristics as important for the absorption of water in natural stone, including composition, structure, texture and pore system. The importance of assessing the movement of water in the stone relative to its bedding and the construction in which it will be placed is emphasized.     

Effect of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete

The main objective of this study is to provide more data on the effects of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete. In the experimental program, mixtures were prepared by partially replacing natural aggregate by expanded perlite and as a result, unit weights of lightweight concretes in fresh state varied between 700 and 2000 kg/m³. Water to cement ratio was kept constant in all mixtures. Compressive strength, modulus of elasticity, water absorption and capillarity coefficient of the mixtures were determined. Thermal conductivity of the specimens was also obtained. Test results show that the compressive strength and modulus of elasticity decreases with increasing in perlite content. Water absorption and sorptivity coefficient, however, increase with the higher perlite contents. The test results indicate that the thermal conductivity is substantially improved with the use of perlite and a strong relationship between thermal conductivity and unit weight is obtained.     

Predicting the core compressive strength of self-compacting concrete (SCC) mixtures with mineral additives using artificial neural network

In this study, an artificial neural networks study was carried out to predict the core compressive strength of self-compacting concrete (SCC) mixtures with mineral additives. This study is based on the determination of the variation of core compressive strength, water absorption and unit weight in curtain wall elements. One conventional concrete (vibrated concrete) and six different self-compacting concrete (SCC) mixtures with mineral additives were prepared. SCC mixtures were produced as control concrete (without mineral additives), moreover fly ash and limestone powder were used with two different replacement ratios (15% and 30%) of cement and marble powder was used with 15% replacement ratio of cement. SCC mixtures were compared to conventional concrete according to the variation of compressive strength, water absorption and unit weight. It can be seen from this study, self-compacting concretes consolidated by its own weight homogeneously in the narrow reinforcement construction elements. Experimental results were also obtained by building models according to artificial neural network (ANN) to predict the core compressive strength. ANN model is constructed, trained and tested using these data. The results showed that ANN can be an alternative approach for the predicting the core compressive strength of self-compacting concrete (SCC) mixtures with mineral additives.     

Effect of salt crystallization on stones of historical buildings and monuments,Konya, Central Turkey

In this study, we investigated the chemical and physical properties of the volcanic rocks used as building stones in historical places and monuments. The chemical weathering effect of salt crystallization on these stones was measured on the laboratory conditions (in most cases, used samples were very small). For this purpose, the dry weight loss (DWL) test was conducted. The rocks of dacite, andesite and tuffs of volcanic origin have different durability against salt crystallization. The most stable rocks are dacites (DWL 2.06%) which were used in the construction of Hittite monuments at Eflatun. The durability of the stones is closely related to their chemical, mineralogical, petrographical and mechanical properties. The stones used in the historical buildings are generally much more stable than present-day building stones.     

Prediction performance of natural gas dehydration units for water removal efficiency using a least-square support vector machine

Natural gas dehydration unit is employed to eliminate water from natural gas liquids and natural gas, and it is needed to avoid condensation of free water and creation of hydrates in transportation and processing facilities, prevent corrosion, and meet a water content condition. In this paper, a least-square support vector machine (LSSVM) coupled with genetic algorithm (GA) was employed to estimate the water dew point of a natural gas stream in equilibrium with a triethylene glycol (TEG) solution at different TEG concentrations and temperatures. Results showed that GA–LSSVM accomplishes more reliable outputs compared with real recorded data in terms of statistical criteria.     

Variation on physico-mechanical properties of Kota stone under different watery environments

The physico-mechanical properties of rocks play an important role in planning and designing of civil constructional works. These properties are adversely affected by acidic and alkaline environments, where they are exposed for a longer time. The natural forces and agents of weathering have degrading effect on the appearance and structural soundness of Kota stone. These agents include rain, temperature, wind and atmospheric pollutants. Weathering agents almost never work individually or in isolation, they always act in combination with one another or with other agents of deterioration.

The durability of building stones is primarily judged by its reactivity with acidic and basic water of different pH values. The conditions are very obvious in any of the large scale construction and use of building stone like sandstones and Kota stones. During the mining of carbonate hosted mineral deposits, the interaction of ground water with ore minerals affect the surrounding environment and rock types. This may cause problem in exploitation of minerals and may cause failure of slope or pillars. To avoid such problems, the prior study of effect of ground water charged with ions released from ore minerals on carbonate rock is important.

In this paper, an attempt has been made to see the variation in the physico-mechanical properties of Kota stone under different watery environment. In the present study, the NX size cylindrical cores were prepared with the help of diamond core drilling machine as per ISRM standard. For each mechanical property, eight samples were prepared and tested. The prepared samples were put into the oven for 24 h at 104 °C to eliminate the moisture present and later submerged in to the water having different pH values ranging from nearly 0.89–12 for 24 h under stirring mode till it gets full saturation at room temperature. The study reveals that there is prominent change in strength properties under acidic and alkaline environments. Rock is considered as a neutral substance so at pH 7, Kota stone shows maximum strength due to non-reactive nature of the solution. Majority of rock mass is not neutral but some of the rock mass shows very minor changes in its strength. The chemical composition of the rock mass dominates the reaction process when it is submerged in varying pH solution.     

污泥资源化新技术——轻质污泥陶粒的研制

干污泥作为原料之一制作陶粒是一种有效的污泥处置方法。试验中选用干污泥、粘土和粘结剂作为主要原料,得到了制备陶粒最佳成分配比和最佳工艺条件是污泥添加百分数为100％（与粘土质量比）、粘结剂添加百分数为20％（与粘土质量比）、烧成温度为950℃、保温时间为20min;产品的主要性能指标是松散容重为519kg／m^3,颗粒表观密度为1110kg／m^3,吸水率为19．6％,空隙率为53．2％;并讨论了原料在烧制过程中的作用、孔隙形成机制和固相反应机理,同时对陶粒进行了物相组成（XRD）和化学成分（XRF）分析。结果表明利用污泥作为添加剂,可以在一定条件下制备出性能优良的陶粒。     

干湿循环对新型固化土承载强度影响的试验研究

 通过模拟一些地区季节性干湿交替的气候变化特征,利用新型击实筒制样进行试验,研究干湿循环对新型固化土承载强度的影响。测试新型固化土在干湿循环交替作用过程中的吸脱湿水量和承载强度,系统分析试件的吸水量、膨胀量和失水量的变化规律以及干湿循环次数对加州承载比值的影响机制。结果表明：在干湿循环作用初期,养生作用促进了固化剂的进一步反应,增强土粒之间的胶结强度,固化土的承载强度表现为逐渐增大,干湿循环达4次时其强度升至峰值;循环超过4次后,以含水量的变化与裂隙性的双重作用为主,促进细微裂纹的扩张、贯通,新裂纹的产生,降低试件的整体性和均一性,其承载强度逐渐衰减。     

再生粗集料混凝土基本性能的实验研究

对再生粗集料的级配、吸水率、表现密度、堆积密度、压碎指标、外观等方面进行实验研究与分析,得出了再生粗集料与天然碎石相比较具有尺寸相似、级配较差、堆积密度和表观密度小、吸水率和压碎指标较高的结果.然后,采用将再生粗集料混凝土与普通混凝土进行对比实验的方法,研究再生粗集料混凝土坍落度、抗压强度、弹性模量、弹强比及抗冻融性能等.结果表明,再生粗集料混凝土具有较好的施工性能、力学性能和耐久性能,可以用于普通钢筋混凝土结构,特别是当再生粗集料替代率在30%及其以下时,与普通混凝土的基本性能相差不大.     

Investigation of the effects of wetting–drying and freezing–thawing cycles on some physical and mechanical properties of selected ignimbrites

This study was performed to investigate the changes in the physical and mechanical parameters of ignimbrites of different colors (black, red, yellow, gray) from Central Anatolia under the influence of wetting–drying and freezing–thawing cycles. For this purpose, 96 NX-size core samples were prepared. The unit weight, specific gravity, apparent porosity, water absorption by weight, slake durability index, uniaxial compressive strength, and P-wave velocity of each ignimbrite sample before conversion were determined. All of these parameters were then redetermined every 10 cycles (for a total of 50 cycles) for each sample. The changes in the values of the parameters after these set numbers of cycles were evaluated statistically. The petrographic and chemical compositions of the volcanic rocks influence their physical and mechanical properties, so some changes were also observed in the ignimbrite samples after these physical processes. Freezing and thawing cycles were observed to have an obvious impact on the physical and mechanical properties of the samples. The greatest changes were observed in black ignimbrite (with ferromagnesian minerals).     

The effect of using different polymer and cement based materials in pore filling applications on technical parameters of travertine stone

The usage of marbles as a natural building and facing stone shows a gradually rising trend in civil sector all over the world. Due to natural motion, structure of marbles consists of many cracks and holes during formation of rocks. Cracks and holes in the marbles generally increase the wastage ratio and operating costs during production of marbles. Normally, the color consistency, brightness of the colors, hardness, strength, non-porous smooth surface as a hygienic structure are desired properties in the usage of flooring and facing stones.In this study, application of some pore filling methods in travertine and their effects on technical parameters of the rock structure were experimentally investigated. Although travertine has high porosity and is composed of different sizes of pores in its structure, it has a wide usage area in the construction and facing stone industry. Its processing is very easy and is much cheaper than the other marble types. Two different applications were mainly used for the pore filling process. These methods are polyester filling technique and cement filling technique. The use of cement filling method is widely applied in travertine production. The effects of these methods on the rock structure were analyzed and the most suitable filling technique was determined based on the technical data of rock parameters.In this study, in addition to the effective use of cement as a filler material in a travertine stone, different ratios of polymer admixtures as a Stuff (ST) and Poliacrilamid (PA) were used to evaluate the collapse of the filling material through the pores with optimum setting time. These materials were used as a replacement of the cement and calcite with the ratios of 0.1%, 0.5%, 1.0%, 1.5% and 2.0%. Test samples were prepared in the form of 40 cm × 40 cm × 1.2 cm tiles and different ratios of the mixture of cement, calcite and polymer materials were applied on the rock surface. These samples were analyzed in terms of water absorption, point load index and unit volume weight measurements by using appropriate standards, TS 699 and ISRM. According to test results, it was tried to compare the filled and unfilled material properties and to obtain optimum ST–PA and cement usage ratio with respect to improving polishing quality, physical and technical parameters of rock.     

Utilization of phosphogypsum as raw and calcined material in manufacturing of building products

The main objective of this research was to investigate the utilization potential of phosphogypsum with fly ash and lime in construction industry. Phosphogypsum was used as raw and calcined material for making the cementitous binder. A series of the tests were conducted to determine the compressive and flexural strength, water absorption and unit weight after 28 days of the specimen preparation. On the basis of the test results, it was concluded that the curing conditions have an important influence on the compressive and flexural strength of the binder specimens. It was also concluded that the cementitous binder obtained can be used for the production of interior wall materials such as bricks and blocks.     

Investigation of humidity harvest as an alternative water source in the Kingdom of Saudi Arabia

In order to harvest water present in a humid atmosphere, a suitable absorber/desorber was designed. Experiments were conducted in Dhahran to measure the water absorption rate in the nighttime and the water desorption rate in the daytime. It was found that the water absorption rate was 2.11 L/m²/day and the water desorption rate was 1.15 L/m²/day depending on the desiccant flow rate. In order to assess the feasibility of the system, the unit was tested continuously in the nighttime as well as in the daytime and the results are reported in this paper. The chemical characteristics of a set of water samples collected were analysed and the water collected was found to meet most of the World Health Organization drinking water standards. The problem associated with this technology is the mixing of dust and dirt with the desiccant solution, and the fact that a small pump is required to circulate the solution.     

The effects of the fiber contents on the mechanic properties of the adobes

In this study, compression and tensile tests were conducted for five different adobe mixtures. The important part of this study consisted of uniaxial compressive tests done with natural fiber mixtures. Thus, the results obtained from mechanical tests were presented in the form of stress–strain graphs. In addition, mechanical properties were related to the water content for workability, unit weight and fiber contents and discussions were given. The results show that as fiber content increases, compressive and tensile strengths decrease, and shrinkage rates decrease.     

Performance of high wokability slag-cement mortar for ferrocement

The performance of high workability mortar mix, applicable for the casting of thin ferrocement elements by using slag as cement replacement and superplasticizer as water reducing agent is investigated. Cement mortars (1:2. 1:2.5 and 1:3) incorporating various percentages of slag and superplasticizer were designed to have high workability (136±3% flow). Performance of the mortars is studied in terms of compressive strength, unit weight, strength development and water absorption. Effect of three different curing regimes on strength and strength development of the mortars is also the part of this study. The results showed that the high workability slag cement mortars of reasonably high strength, low water absorption and exhibiting early age strength comparable to that of the OPC mortars can be designed in order to cast thin ferrocement elements by the method of pouring.     

Some engineering properties of natural building cut stones of Cyprus

Natural building cut (NBC) stones are being used in Cyprus for ages to build masonry structures because of being abundant, relatively easy to cut and shape and good performance in many applications. Almost all of the historical buildings in Cyprus are made of these NBC stones. Although these stones are low cost construction materials, they are not widely used in these days. This is due to lack of knowledge causing incorrect construction methods and highly skilled labour requirement.For this study two quarries are selected and samples obtained were tested for some physical and mechanical properties. Traditional names of these NBC stones are Meluşa Stone and Karpaz Stone (or Bouri Stone). The physical properties such as bulk density, water absorption, specific gravity and porosity were measured. The mechanical properties such as compressive strength, flexural strength, direct tensile strength, splitting tensile strength, point load strength, fire resistance, abrasion resistance and freeze-thaw resistance were measured. From the results obtained it can be said that Meluşa stone behaved better than Karpaz stone. A regression analysis also provided a polynomial relation between compressive strength and burning temperature and flexural strength and burning temperature.     

以大理石废料与回收塑料为原料研制聚酯混凝土

以苯乙烯改性聚酯(SP)与大理石废料为原料研制聚酯混凝土(PC).所用的不饱和聚酯(UP)是PET塑料与醋酸酐及脂肪酸发生解聚所生成的聚合物反应后所制得.之后将UP与苯乙烯单体按重量比60∶40的比例混合制成SP,进而研制出PC.研究目的是探讨PC作为聚酯基建筑材料使用的适应性.以大理石废料与PET塑料瓶为原料研制PC,减少废物的积累,对环境保护起到积极作用,同时因节省其他填充材料的消耗而产生经济效益.该文还探讨了在不同实验条件下PC试块的力学性能,同时通过测试其抗化学腐蚀性和吸水性评价其耐久性.从所得数据可以作出结论,该PC在20%Na2CO3、10%NaOH溶液、自来水、地下水和海水中具有好的抗化学腐蚀性.除此之外,所研制的PC视孔率低,吸水率低,空隙小.     

A preliminary study on the conservation and polishing performance of Sanliurfa limestones as a traditional building material

Sanliurfa limestones have been used as building materials from antiquity to current day (e.g., Gobeklitepe temple B.P. 14,000, Bazda underground quarries B.P. 3000, Harran castle B.P. 3000, etc.). These antique structures are listed within the United Nations Educational, Scientific and Cultural Organization (UNESCO)’s World Heritage List. However, the stones were used in these structures without any protection, and atmospheric conditions (precipitation, acid rain, temperature changes, etc.) cause damage to these stones over time, such as strength loss, abrasion, and discoloring. The damage can lead to the collapse of precious historical structures, or may require costly restoration. In this study, Sanliurfa limestone was investigated with respect to conservation using polish insulation (polysiloxane, lithium silicate, and varnish), appearance performance by polishing, and potential usage in the marble industry. The results revealed that conservatives could maintain up to 92 % of the unconfined compressive strength (UCS) of the natural stone and reduced acid abrasion to 0.5 % of the original weight. The stone gained a bright appearance after polishing, especially by lithium silicate. Thus, it can be stated that it is possible to recover or prolong the lifetime of the monuments that were constructed using Sanliurfa limestone, and this limestone may have great industrial potential as marble stone.     

The using of waste phosphogypsum and natural gypsum in adobe stabilization

The best known disadvantages of adobe are its low mechanical properties and poor resistance to water damage. In this research waste phosphogypsum (PG) and natural gypsum were used as stabilization material to improve the properties of adobe soil and to reduce its disadvantages at least partially. The compressive and flexural strength, softening in water, drying shrinkage and unit weight values were determined on adobe samples. The strength values of adobe samples increased with both gypsum additions. The most resistance of the adobe samples against softening in water was obtained with 25% PG addition. Drying shrinkage of test samples reduced with increasing PG content. The dry unit weight of the specimens was not in the recommended range specified in the standards. Test results showed that PG can be used as alternative material in adobe stabilization to bring economy and to reduce environmental pollution.