Researches show that concretes containing 25 to 35 % slag powder (as alternation for Protland cement) obtain Compressive Strength CS about 85% and 97% of the control specimens (without slag) at the ages of 28 and 90 days respectively. These concretes, also, recorded less growth rate of the CS than the control specimen at early ages (<28 days). In order to increase the early CS of these concretes and acquire 28-daysold CS about control specimens, this investigation was carried out using various percentage of the silica fume replaced with known quantities of Prortland cement. The results revealed that specimens containing 5% silica fume along with 25 to 35% slag powder displayed 5.2% and 13.3% higher than CS of control specimens at the 28 and 90 days respectively. In other part of the study the CS of the concretes containing slag powder cured with water comprising 2.5% MgSo4 as well as 2.5% NaCl were evaluated. Slag-contained specimens, which were placed in above mentioned curing situation, showed less CS at 28 days than control specimens whereas at the age of 90 and 180 days CS of the specimens were higher than the control specimence. The 25% slag-contained speciemens placed in sulphated situation at 180 day old stage showed 325 Kglcm2 CS which was 14.44% higher than the control sample attaining the best result. here with material and geometric nonlinear analysis. In this paper, buckling behavior and ultimate capacity of built up castellated compound columns are investigated using ANSYS software. A brief of results is reported on for a number of CPE sections in different boundary conditions. Also is presented slenderness-load curve by using of Jandel software, which is a useful tool for investigation of ultimate capacity of the columns.

Nowadays, the better performance of lightweight structures during earthquake has resulted in using lightweight concrete more than ever. However, determining the Compressive Strength of concrete used in these structures during their service through a none-destructive test is a popular and useful method. One of the most original approach of non-destructive testing to obtain of Compressive Strength of concrete used in structures is ultrasonic pulse velocity test. The purpose of this research is predicting the Compressive Strength of LWA concrete by proposing an accurate mathematical formulation. Many samples of lightweight aggregate concrete, made by expanded clay, have been produced and tested. After determining the actual Compressive Strength and indirect ultrasonic pulse velocity for each sample, a relationship was derived to estimate the Compressive Strength through Gene Expression Programming (GEP). The results show the presented equation shows high accuracy in predicting the Compressive Strength of LWA and the estimated outcomes have a considerable compatibility with actual samples.

This study introduces, two models based on Gene Expression Programming (GEP) to predict Compressive Strength of high Strength concrete (HSC). Composition of HSC was assumed simplified, as a mixture of six components (cement, silica fume, super-plastisizer, water, fine aggregate and coarse aggregate). The 28-day Compressive Strength value was considered the target of the prediction. Data on 159 mixes were taken from various publications. The system was trained based on 80% training pairs chosen randomly from the data set and then tested using remaining 20% samples. Therefore it can be proven and illustrated that the GEP is a strong technique for the prediction of Compressive Strength amounts of HSC concerning to the outcomes of the training and testing phases compared with experimental outcomes illustrate that the.

Objectives: Maintaining pulp vitality is a main goal in restorative dentistry. Introduction of pulp capping agents paved the way to eliminate the shortcomings of these materials and obtain successful restorations. On the other hand, nanotechnology is an emerging field of science with increasing use in dental materials. This study sought to assess the effect of addition of nano-TiO2, nano-SiO2 and nano-Al2O3 on Compressive Strength of five hydraulic cements.Methods: In this in vitro, experimental study, three experimental formulations of nano hybrid MTA, MTA Angelus and MTA Angelus+nano-oxide particles cements were placed in molds measuring 4±0.1mm in internal diameter and 6±0.1mm in height made of stainless steel (ISO9917-1). Ten samples were fabricated for each of the five groups of materials. Sound samples were stored at 37oC and 95±5% humidity and were subjected to Compressive Strength testing in a universal testing machine at a crosshead speed of 0.5mm/minute after 24 hours and one month. Two-way ANOVA, one-way ANOVA and independent samples t-test were used for comparison of Compressive Strength of groups at different time points.Results: The highest Compressive Strength belonged to MTA Angelus+nanohydroxyapatite and nano-hybrid MTA C at 24 hours and 30 days, respectively. The lowest Compressive Strength belonged to nano-hybrid MTA B and MTA Angelus at 24 hours and 30 days, respectively (P<0.05).Conclusion: Addition of nanoparticles affected the Compressive Strength of cements. Compressive Strength significantly increased over time in all groups.

Accurate prediction of the uniaxial Compressive Strength (UCS) of concrete is crucial for ensuring the safety, durability, and performance of structures in construction. This study presents a predictive model using a multilayer perceptron (MLP), to estimate UCS based on key input parameters such as water-cement ratio, aggregate size, curing time, water and cement content. The MLP model was trained and validated using a dataset comprising 120 cubic laboratory-tested concrete samples (15cm × 15cm × 15cm) with varying compositions for normal construction materials. Performance of the model was evaluated using statistical metrics (split into training and testing sets as 70%-30%), showing that the MLP-based approach provides accurate and reliable predictions compared to traditional regression models. The proposed method offers a practical, efficient tool for geotechnical engineers to assess concrete Strength, potentially reducing the need for extensive experimental testing and enhancing quality control in concrete production.