The production of concrete consumes huge amounts of natural resources. Due to the consumption of natural resources for cement production, using industrial waste materials has gained interest among researchers. Environmental issues are one of the most important issues that should be taken into consideration. Zeolite and bentonite are considered as natural pozzolans, they are easy to extract and count as environmentally-friendly raw material compared to ordinary Portland cement (OPC). In the current study, these materials were utilized blended with other materials and individually. Compressive strength, water absorption, tensile strength, and elastic modulus of concrete samples were evaluated. Moreover, 10 different mixing designs were designed to produce samples in the same curing condition with different content of bentonite and zeolite. These samples were cured for 7, 28, and 90 days. To investigate the properties of these materials as an alternative to OPC in the concrete, the results are compared with the blank sample. The optimum mixture was obtained by 6 wt. % of zeolite and 6 wt. % of bentonite, which was gained 93% of the compressive strength of the blank sample, i. e., 12. 25 MPa, after 28 days of curing. This study also showed that the water absorption of samples with zeolite and bentonite had increased in comparison with the blank sample and the optimum amount in tension was observed 10 wt. % of bentonite.

In recent decades, the use of mass concrete in various infrastructure projects has significantly increased. Due to the larger dimensions of these sections and the higher volume of Portland cement, a decrease in the strength and durability of the core is often observed in these concrete sections. Industrial by-products such as blast furnace slag have increasingly been used as additives to produce mass self-compacting concrete. This research aims to control and reduce the peak temperature of mass concrete by replacing blast furnace slag with cement. Considering the relevant regulations, the study investigates the reduction or prevention of delayed ettringite formation and the reduction of concrete heat. Additionally, the enhancement of the durability, strength, and performance of self-consolidating concrete for large sections is evaluated. In this manner, four concrete mix designs with replacement percentages of 35%, 45%, and 55% blast furnace slag with cement, and one control mix design (with zero percent blast furnace slag replacement) were employed. To achieve a more detailed analysis of the impact of adding this material to mass self-consolidating concrete, various tests were conducted on fresh and hardened concrete as well as cement. The results indicate that with an increase in blast furnace slag replacement up to 55%, the cement heat has decreased by 28.79%. The workability of self-consolidating concrete using this cement has increased by 7.9% and 5.5% in slump flow and L-box tests, respectively, and good improvements in other performance tests have been observed. In mechanical tests, the concrete strength decreased at early ages with an increase in blast furnace slag but increased at later ages. In durability tests, the concrete's durability increased with up to 55% blast furnace slag replacement, and the increase in electrical resistivity was 14%.

In recently years, there has been an increase in the use of industrial and agricultural residues in the production of concrete. Thousands of tones of these agricultural residues and industrial bypro ducts are produced every year. Therefore, the study of their characteristics and possible applications becomes a priority as their use brings benefits in technical, economic, power and environmental terms. Different materials with pozzolanic properties such as silica fume, fly ash, blast-furnace slag, rice-husk ash and bagasse ash have played an important part in the production concrete. This paper presents a laboratory study on the properties of mortar containing "Karun Argo Industries Co." bagasse ash and Different materials with pozzolanic properties. For this purpose-A total of 19 mixtures with different mix designs were prepared, 9 of them with baggase ash, 3 mixes with rice-husk ash, 3 mixes with silica fume and 3 mixes with truss were prepared. These different pozzolanic materials was added as partial cement replacement. 1 mix was prepared as control mixture. This research shows that bagasse ash, could be used as a pozzolanic material to produce concrete.

Scrap tires are counted as one of the non-recyclable materials in nature, which cause environmental mal-effects. In the present research, the feasibility of applying scrap tire rubber in concrete is investigated. In this regard, some laboratory specimens are made and tested in two major groups. In the first group: crumb rubber was used instead of coarse aggregate and, in the second group, ruboer powder was used instead of cement. A compressive strength test was done to recognize the strength behavior of the specimens and to investigate their durability under different conditions, two of the most significant tests (including: permeability and water absorption) were done.The results revealed that the trend of strengthening in a 28-day-period could be determined via an experimental equation, which is conservative, and their compressive strength is similar to ordinary concrete.It is also to be mentioned that no significant changes in durability will occur, if the substitution percentage does not exceed a special limit.

Soil properties improvement involves a variety of approaches. Among them, the addition of specific materials to the soil has been widely adopted in the literature. Cement's impact on the environment is negative, but it has been widely used in many construction projects. The main purpose of this research is to find suitable alternative methods to decrease cement usage, one of which is the addition of polypropylene fibers and zeolite. 126 types of unconfined compression tests with different ingredients were carried out with the aim of decreasing cement usage and improving soil properties. Two types of sandy soil were adopted in this study, i.e., SP and SW soil. They were improved by 4% cement, 0, 0.25, 0.5, 0.75, and 1% of polypropylene fibers with random distribution, and 0, 10, 30, 50% of zeolite were used during curing periods of 7, 14, 28 days. According to the compaction test results, with the addition of 0.5% polypropylene to the SW soil, and 1% to SP soil, the value of optimum moisture increases and then decreases. On the other hand, the addition of polypropylene fibers resulted in the decrease of the special dry weight of both types of soils. It also revealed the optimum percentage of zeolite and polypropylene fibers in SW soil are 30% and %0.5, respectively, while this values in the SP soils are 10% and %0.75, respectively. The proper adoption of zeolite and polypropylene in cement led to an increase in unconfined compression tests as well as elastic deformation strength.

Drict discharge of domestic wastewater (sewage) to the environment or into absorbing wells has caused many problems including surface and groundwater pollution. To reduce such problems, the number of wastewater treatment plants has increased significantly in Iran during the last two decades. During wastewater treatment, a significant amount of sludge, composed of organic and mineral material, is produced. This sludge, if not handled and disposed properly, can create serious environmental and health issues. One environmentally attractive way of dealing with such wastes is to use them in different types of applications. In this regard, many economical and beneficial methods have been developed to reuse sludge. Incineration of sludge for energy recovery or the use of sludge ash in cement-based construction materials are among these methods. Sludge incineration produces considerable amount of ash which should be disposed. However the ash can be used as cement substitude in procuction of cement-based material. The subject of using sludge ash as cement substitude has been investigated by a few researcher with the conclusion that the usage of ash can affect the final cement-based product quality. Based on their experimental results, the use of sludge ash tends to decrease the workability of fresh mortar or concrete, and to increase the cement setting time. Also a decrease in compressive strength of mortar or concrete was reported. However, it should be mentioned that no research has yet been done to investigatethe the effects of sludge ash replacement on mechanical and durability properties of concrete. The main aim of this study was to investigate the effects of sludge ash usage as cement substitude on physical, mechanical and durability properties of concrete. For this purpose, the effects of three key parameters: replacement level (0-20%, by weight), curing times (7, 28, 91 and 180 days) and water-cementitious material ratio (0.35, 0.45 and 0.55) were investigated. The sludge used in this research was obtained from one of the local wastewater treatment plants, which subsequently was dried and then was incinerated at 800oC to produce ash, The ash was in general, made up of irregular grains which were aggregates of smaller particles. Also, the ash was composed mainly of calcium, silica and aluminium oxides. The results showed that increasing the amount of sludge ash induced higher mortar setting times as compared to the control samples, using Vicat test. The effect of ash content on mechanical properties of concrete samples was carried out by compressive strength tests. Results indicated that for 7 and 28 days curing time, concrete samples containing a mixture of sludge ash and cement yielded lower compressive strength values than those samples using only cement (without any ash content). However, for curing times greater than 28 days, the increase in ash content of concrete samples (in the range of 0-15% by weight) led to an increase in compressive strength. Water absorption and electrical resistivity tests were conducted to determine the durability of concrete containing sewage sludge ash. As blending percentages of ash content increased fom 5% to 20% (by weight), electrical resistivity of concrete samples decreased for regardless of the applied curing times. This phenomenon might be the result of increased porosity and material ionization.